Zr(1)2H was obtained as a racemate, which was resolved by HPLC and the enantiomers were isolated in >99.5 % ee. Their absolute configurations were assigned on the basis of X‐ray crystallography and circular dichroism spectroscopy. Vibrational circular dichroism (VCD) experiments on the enantiomers of 2Zr(1) revealed that the chirality around the zirconium center is propagated throughout the whole cage structure. The axial conformational chirality of the double cage complex displayed a VCD fingerprint similar to the one observed previously for a related chiral cage compound with planar and point chirality. 2Zr(1) shows fluorescence, which is quenched when viologen guests bind in its cavities. The binding of viologen and dihydroxybenzene derivatives in the two cavities of 2Zr(1) occurs with negative allostery, the cooperativity factors α (=4 K2/K1) being as low as 0.0076 for the binding of N,N’‐dimethylviologen. These allosteric effects are attributed to a pinching of the second cavity as a result of guest binding in the first cavity.Chiral zirconium(IV) double cage sandwich complex  Starting from achiral porphyrin cage compounds, chiral zirconium(IV) double decker porphyrin cages have been prepared and their enantiomers resolved. The binding of two viologen guests in the double decker porphyrin cages occurs via a strongly negative allosteric effect, resulting in an almost 3 orders of magnitude weaker binding of the second viologen guest compared to that of the first. For the additional binding and catalytic conversion of substrates, more sophisticated porphyrin architectures, in which specific substrate‐recognition functionalities[21H  acts as a biomimetic catalyst in the epoxidation of low molecular weight[Zn1 is enhanced when a bulky pyridine ligand coordinates to the zinc center at the outside of the cage molecule.[To mimic the action of porphyrin‐containing enzymes, a wealth of synthetic model systems have been constructed in which porphyrins are provided with bulky substituents, caps, and straps.4, 5 M22H   center. The resulting sandwich complex, which is readily obtainable in >100 mg quantities, has a twisted structure and is chiral. We were able to resolve the racemate and determine the absolute configuration of the enantiomers by X‐ray diffraction. 2Zr(1) was found to bind viologens and resorcinol derivatives via negative allosteric cooperativity as a result of structural reorganizations throughout the whole double cage complex upon consecutive binding of the guest molecules.Along our efforts to develop porphyrin double cage compounds, we previously reported on 2 Figure  in whichFigure Zr2  was synthesized in 33 % yield and in substantial quantities (up to 160 mg per batch) by stirring the free base porphyrin cage compound 21H with freshly prepared Zr(Et2N)4 in refluxing toluene. The same approach had previously been used by Kim et al. to prepare Zr(TPP)2 (TPP=tetrakis‐meso‐phenyl porphyrin), i. e. the double decker porphyrin complex without glycoluril‐based cages.2v‐symmetric porphyrin cages, the product is obtained as a racemic mixture of (M)‐ and (P)‐enantiomers  turned out to be very stable against thermal racemization, as refluxing a solution of the pure enantiomer 2(+)‐Zr(1) in toluene for 18 h did not result in any changes in its CD spectrum . This result is in line with previous reports on other chiral zirconium porphyrin sandwich complexes, which were also inert to thermal racemization.Double cage compound 2(−)‐Zr(1), which turned out to correspond to the (M)‐isomer ‐Zr(1) were of insufficient quality to perform an absolute structure determination. The unit cell of the crystal contains two molecules of 2(−)‐Zr(1). The overall coordination geometry around the zirconium center is square antiprismatic. The porphyrin cages of these two molecules are rotated relative to each other by angles of 47° in one double cage molecule in the unit cell, and 58° in the other molecule, which is somewhat larger than the angle of 37° reported for Zr(TPP)2.[2.[2.[2, these angles ranged from 9.9° to 24.2°,[2(−)‐Zr(1) they vary from 11.2° to 26.2°, indicating that the porphyrins in 2(−)‐Zr(1) are slightly more distorted than those in Zr(TPP)2. The average distance between the protons H‐30 ‐Zr(1), indicating a slight elongation of the cavities in the latter complex, presumably due to the distortion of the porphyrin planes.The absolute configurations of the enantiomers could be assigned on the basis of the X‐ray structure of the compound that eluted second from the column during the purification CCDC 2023416), i. e. 416, i. eZr(TPP)2.52, 542(±)‐Zr(1) in most common solvents and solvent mixtures turned out to be quite low, i. e. <1 mg/mL, except in dichloromethane, in which the compound showed a relatively high solubility of ≈5 mg/mL. We rationalized that in the poor solvents 2(±)‐Zr(1) was prone to aggregation. To further investigate the ability of 2(±)‐Zr(1) to self‐assemble, droplets of solutions of racemic and enantiopure 2Zr(1) in 1‐phenyloctane (c≈10−4 M) were brought onto a freshly cleaved surface of highly oriented pyrolytic graphite (HOPG) in a scanning tunneling microscope (STM) operating at a solid/liquid interface. The pure enantiomers failed to form stable monolayers, but for the racemate extended domains of self‐assembled lamellar arrays, containing near‐rectangular features with dimensions close to that of a 2(±)‐Zr(1) molecule were observed ‐Zr(1) and is defined by vectors with dimensions a=3.5±0.2 nm and b=2.4±0.15 nm, under an angle of 93±2°. Although the near‐rectangular features contain sub‐molecular features, the structure of 2(±)‐Zr(1) cannot be directly identified in them. This is not surprising, given the fact that the adsorbed double cages are large 3D architectures of which the aromatic and aliphatic parts are superimposed from the point of view of the STM probe. Nevertheless, two types of roughly equally sized near‐rectangular features can be discerned, differing in brightness, which alternate along each of the lamellar arrays. The observed difference in brightness may be caused by (i) the alternating adsorption of the (M)‐isomer and the (P)‐isomer of 2(±)‐Zr(1), (ii) two different adsorption geometries of the double cage molecules , or (iii) a combination of these two possibilities. Unfortunately, the complex appearance of the rectangular features prohibited identification of either the isomer identity or the cage orientation. A molecular model was constructed assuming the possibility that both enantiomers of 2Zr(1) adsorb on the surface, i. e. as a 2D racemate ‐Zr(1)  is stabilized by intermolecular π‐π stacking interactions between the meso‐phenyl rings of adjacent porphyrin planes, while between the lamellae the phenyl rings of the glycoluril frameworks of the double cages are within Van der Waals contact distance. As mentioned above, a stable monolayer of the racemate formed readily at the solid/liquid interface, while multiple attempts to construct and image stable monolayers of the pure enantiomers failed. This might imply that the presence of both enantiomers of the double cage compounded is required for the formation of a stable layer. However, since layer formation at a solid/liquid interface can be quite unpredictable and is dependent on a variety of conditions, such a conclusion may be premature and requires additional research.The solubility of ane c≈10− M were bane c≈10− M were b2(±)‐Zr(1) in solution was investigated by means of 1D and 2D NMR spectroscopy, which allowed the assignment of all proton and carbon signals. Compared to the 1H NMR spectrum of 21H, the spectrum of 2(±)‐Zr(1) . The porphyrin β‐pyrrole protons were assigned based on the observed shifts of their signals upon the inclusion of viologen guests G1 inside the cavities (vide infra): the signals of protons H‐3, H‐4, H‐13, and H‐14, which are located directly above the large cavity openings in which the guest binds, experience significant downfield shifts upon binding, while the signals of protons H‐8, H‐9, H‐18, and H‐19 barely shift ‐Zr(1) are shifted significantly downfield (+1.63 and +1.45 ppm compared to 21H) as a result of their location in the deshielding zone of the close‐by porphyrin of the second cage in the sandwich complex. The distortion in the porphyrin planes results in a decrease in their aromaticity, causing an upfield shift of the β‐pyrrole signals compared to 21H. Simultaneously, the X‐ray structure shows that the meso‐phenyl rings are slightly tilted with respect to the porphyrin plane, which is likely the result of the distortion of the latter plane, combined with the steric hindrance imposed by the other, nearby porphyrin ring. This tilting in turn seems to cause the oxyethylene protons H‐27 and H‐28 to rotate to the inside of the cage and into the shielding zone of the porphyrin, resulting in strong upfield shifts (up to −1.32 ppm) of their proton signals in the NMR spectrum compared to those of 21H.The structure of 2 Figure  is more 2 Figure  chemical2(±)‐Zr(1) were investigated by means of cyclic voltammetry, and compared to the properties of other zirconiumporphyrin sandwich complexes and the non‐metallated parent porphyrin cage 21H ‐Zr(1) and 21H display two reversible oxidations and one reversible reduction of the porphyrin ligand. For both 2(±)‐Zr(1 ) and 21H, no second reduction was observed due to the limits of the combination of solvent and electrolyte. Compared to 21H, 2(±)‐Zr(1) is easier to oxidize and more difficult to reduce, which indicates that both the HOMO and the LUMO of 2(±)‐Zr(1) are higher in energy than those of 21H. The same trend is visible for TPP and Zr(TPP)2.2 it was hypothesized that the energy rise of the HOMO is the result of π‐π stacking interactions between the porphyrin planes.The redox properties of 1 Figure , Table 1(±)‐Zr(1)2 is easier to oxidize and more difficult to reduce compared to Zr(TPP)2, which is likely the result of the more electron‐rich porphyrin because of the alkoxy substituents at the meso‐phenyl groups. A similar redox behaviour was reported for a porphyrin with meso‐o‐methoxyphenyl substituents (T(o‐OMe)PP), of which the oxidation potentials are ∼0.1 V lower than those of TPP.Compound 21H in CH2Cl2, the Soret band of (±)‐Zr(1)2 is blue‐shifted by ∼20 nm to 398 nm ‐Zr(1), which corresponds to a clockwise orientation of the porphyrin planes, and thus this enantiomer is the (P)‐isomer.2(−)‐Zr(1), displays a left‐handed couplet at 398 nm, which is in agreement with an anti‐clockwise orientation (M) of the porphyrin rings, which in turn corresponds to the X‐ray crystallography data. The Q bands around 500 and 550 nm are also weakly CD‐active, and other strong CD signals are present in the high‐energy region between 250 and 350 nm.Compared to the porphyrin Soret band in the UV‐vis spectrum of m Figure A. This i2(+)‐Zr(1) and 2(−)‐Zr(1) in CD2Cl2 displayed many vibrations of the receptor‐parts of the molecules, implying that the chiral environment around the zirconium(IV) center is propagated to the entire cage structure ‐Zr(1) and Sp‐‐23H both exhibit four characteristic positive bands at 1253, 1285, 1330/1336 and 1375 cm−1, and a negative‐to‐positive couplet at 1705–1728 cm−1 . The positive band at 1336 cm−1 for Sp‐‐23H is dominated by vibrational modes of deformations of the porphyrin part. In 2(+)‐Zr(1), the formation of bonds with the zirconium(IV) center leads to a red shift of this band of 6 cm−1. The characteristics of this band  can be related to the concave geometry adopted by the porphyrin in both molecules Sp‐‐23H and 2(+)‐Zr(1). The complexation of the cage with zirconium(IV) significantly emphasizes this concavity. Similarly, the sign and intensity of the couplet, which results from the mixing of the two C=O stretching modes, depends on the relative asymmetry of these functional groups in the most abundant conformations of Sp‐‐23H and 2(+)‐Zr(1).[The VCD spectra of the enantiomers e Figure A−B. Stri(+)‐Zr2 and (−)2(±)‐Zr(1), an intense band at 658 nm in the emission spectrum appeared . This emission was determined to be fluorescence based on lifetime measurements . About 60 % of the fluorescence was quenched when oxygen was bubbled through the sample for 3 minutes .Upon irradiation of the Soret band of 2Zr(1) and methyl viologen  (G1), and to study cooperative effects between the binding of the first and second guest, a fluorescence titration was carried out ‐Zr(1) 3.0 μM in CH2Cl2/CH3CN, 1 : 1 (v/v) caused quenching of the fluorescence (a solvent mixture was employed since neither the host nor the guest are sufficiently soluble in a single solvent). Fitting of the titration data to a 1 : 2 host‐guest stoichiometry revealed that the second viologen guest is bound almost 3 orders of magnitude weaker than the first one , indicating a strongly negative cooperative effect with an α‐value (4 K2/K1) of 0.0076. It should be noted that the first part of the titration curve could not be fitted completely, leading to somewhat higher errors. Interestingly, the binding of the viologen guest resulted not only in the fluorescence quenching of the adjacent porphyrin, but also in a partly fluorescence quenching of the porphyrin on the opposite side of the zirconium center. This can be concluded from the fact that the fluorescence at 1 equivalent of added G1 is not 50 % but 35 %, i. e. 65 % is quenched . During the first part of the UV‐vis titration  a clear isosbestic point was observed at 400 nm ‐Zr(1) and G1 induced the emergence of a new CD signal between 350 and 390 nm, but due to a poor signal to noise ratio the determination of the K‐values in a titration experiment turned out to be rather unreliable.To investigate the binding strength between 1H NMR spectrum of the 1 : 2 complex between 2(±)‐Zr(1) and G1 in CD2Cl2/CD3CN 1 : 1 (v/v) indicated a similar binding geometry of the viologen guests as in the case of 21H. The downfield complexation induced shifts (CIS) of the signals of β‐pyrrole protons H‐3, H‐4, H‐13, H‐14 and the upfield shifts of the cavity side‐wall protons H‐30 upon the binding of G1 ‐Zr(1) significant downfield shifts were observed for several of the signals of protons H‐27 upon binding of the guests. We attribute these shifts to a structural reorganization of the host in which the ethyleneoxy spacers move out of the shielding zone of the porphyrin by rotating outwards, thereby generating space in the cavities to accommodate the large viologen guests (induced‐fit). All proton signals of the guests were very broad, which is attributed to fast exchange between bound and unbound species. Compared to the complexation of G1 in 21H,2(±)‐Zr(1) is bound significantly stronger, and the second one significantly weaker. The difference in the Gibbs free energy of binding of G1 in the two cavities of 2(±)‐Zr(1)  is 15.1 kJ mol−1.The 1 Figure , Table 3K1 and K2, solutions of 2(±)‐Zr(1) and of this host in the presence of one and two equivalents of G1 were investigated by 1H NMR spectroscopy at 245 K. This low temperature was chosen in order to induce slow host‐guest exchange in the complexes. The spectra of 2(±)‐Zr(1) and of the 1 : 2 host‐guest mixture resembled the room temperature spectra, while the spectrum of the 1 : 1 host‐guest mixture showed a doubling of many of the proton signals ‐Zr(1). As a result, the two cavities are no longer equivalent, resulting in different chemical shifts for previously identical protons. The four signals of the side‐wall protons are located at positions that are distinctly different from the positions of the side‐wall proton signals in the free host and the 1 : 2 host‐guest complex. This is further evidence for the presence of predominantly a 1 : 1 complex when one equivalent of G1 is added. The upfield shift of the signals of proton H‐30 indicates that also in the 1 : 1 complex the guest binds with its aromatic rings parallel to the xylylene side‐walls.2(±)‐Zr(1) (0.24 mM) at low temperature we were unable to employ 2D NMR techniques to further characterize the precise geometry of the 1 : 1 complex.In an effort to confirm the large difference in the association constants s Figure B and canG1 in 2(±)‐Zr(1) shown in Table 22H ‐Zr(1), since the two receptor cavities are structurally connected via their coordination to the zirconium center.The association constants for the binding of 2(−)‐Zr(1) and its 1 : 1 and 1 : 2 host‐guest complexes with G1 by molecular modelling . The calculated energy‐minimized structures ‐Zr(1), depending on the presence or absence of guest molecules. As an indication of these widths, the distances between protons H‐30 of the two cavities at opposite xylylene side‐walls are summarized in Table To investigate this possibility, we calculated the structures of the free host s Figure  show sig‐π stacking with the xylylene side‐walls of the host and with the porphyrin plane.G2, G3R, and G3S in the cavities of 2(±)‐Zr(1) was investigated with the help of 1H NMR titrations. The titration curves for the binding of G2 in 2(±)‐Zr(1) could only be fitted to a binding equilibrium assuming the formation of a 1 : 2 host‐guest complex, and provided K1 and K2‐values which are summarized in Table 2(±)‐Zr(1) with their aromatic surface parallel to the xylylene side‐walls, thereby strongly shifting upfield the signals of particularly the ethyleneoxy protons H‐27 and H‐28. These upfield shifts indicate that, in contrast to what was observed for the binding of G1, the binding of the smaller guest G2 does not lead to a significant movement of the ethyleneoxy spacers of 2(±)‐Zr(1) out of the porphyrin shielding zone, and hence suggest that the host requires no or much less rearrangement during binding than in the case of G1. The proton signals of the guest were again broad due to fast exchange between bound and unbound species. Interestingly, the first G2 guest was found to bind an order of magnitude stronger in 2(±)‐Zr(1) than in 21H. This enhanced binding is attributed to the stretching of the cavities of the double cage complex. Since the aromatic ring of a resorcinol derivative bound in a glycoluril‐based clip molecule is clamped in a position slightly above the xylylene side‐walls of the cavity,2Zr(1) along the z‐axis, together with the distortion of the porphyrin plane, provides more space for the guest compared to the binding in 21H. For the binding of the two G2 guests, an α‐value of 0.53 was observed, which is a much less prominent negative binding cooperativity than was found for the binding of G1. Molecular modeling calculations of the complexes of 2(−)‐Zr(1) with G2  reveal that a similar, but less pronounced, allosteric effect is operative as in the complexes of the host with G1. Upon binding the first G2 guest in cavity 1, the latter expands somewhat compared to the previously empty cavity, but significantly less than when it binds G1 ‐Zr(1) with G1, where the binding of the second guest leads to a more overall rearrangement of both cavity spaces. This requirement for more extensive rearrangement of the host is in line with the observed much more pronounced negative allosteric cooperativity for the binding of G1 in 2(±)‐Zr(1).In addition to viologens, resorcinol  derivatives are also suitable guests for the porphyrin cage compounds. Figure S6 reveal 2(+)‐Zr(1) and 2(−)‐Zr(1) to enantioselectively bind chiral resorcinol derivatives G3R and G3S ‐Zr(1). The lower binding affinities for guests G3 are ascribed to their bulky 5‐substituents, which have more steric interactions with the porphyrin roof of the hosts. The CIS‐values obtained from the NMR titrations again show strong shielding of the ethyleneoxy protons H‐27 and H‐28 of the hosts upon guest binding, indicating that the host‐guest binding geometries are similar as those in the complex between 2(±)‐Zr(1) and G2 (Table S32). Because of their size, the ethoxycarbonyl substituents of G3R and G3S are probably directed to one of the cavity portals, which causes the methyl groups connected to the chiral center to point to one particular side of the cavity . As a result, one set of ethyleneoxy proton signals shifts more upfield than the other set. This effect is mirrored in the diasteromeric complexes and similar in the enantiomeric host‐guest complexes. Despite the relatively weak binding, still negative cooperativity was observed, with α‐values in the same range as those found for the host‐guest complexes between 2(±)‐Zr(1) and G2.In a final set of experiments we explored the potential of the enantiopure hosts 2Zr(1) was synthesized in a single step from 21H in a yield of 33 %. Its enantiomers have been resolved with excellent enantiomeric excesses and their absolute configurations could be assigned based on the crystal structure of 2(−)‐Zr(1), and were confirmed by circular dichroism spectroscopy. With the help of STM, the double cage complexes could be imaged at the sub‐molecular level in a self‐assembled monolayer of the racemate on a graphite surface, which was not possible with either of the pure enantiomers. VCD experiments of the enantiomers of 2Zr(1) revealed that the chirality around the zirconium center is propagated throughout the whole cage structures. The VCD fingerprints are rather similar to the ones previously reported for the enantiomers of cage 23H. This represents a rare case in which the VCD spectra reflect a similarity between a molecule with axial chirality and a molecule with planar and point chirality. The double cage sandwich complexes formed 1 : 1 and 1 : 2 host‐guest complexes with viologen and 1,3‐dihydroxybenzene derivatives. No enantioselective binding of chiral 1,3‐dihydroxybenzene derivatives in the homochiral double cage complexes was observed. The binding of all guests showed negative cooperativity, i. e., the binding strength of the second guest was always weaker than that of the first one. The negative cooperativity is the result of allosteric effects, as the NMR data revealed a clear structural reorganization throughout the structure of both porphyrin cages upon the binding of the guests. Molecular modelling calculations confirmed these reorganizations and indicated that the binding of a guest in the first cavity of the double cage complex causes a narrowing of the second cavity, thereby disfavouring the binding of the second guest. The negative allosteric cooperativity was most pronounced for the binding of the large viologen guests, which require more structural reorganization of 2Zr(1) than binding of the much smaller dihydroxybenzenes.Double cage sandwich complex 2Zr(1) with a catalytic functionality, however as the zirconium center of 2Zr(1) only serves as a non‐catalytic coordination site, we intend to provide the xylylene side‐walls of the double cage complex with oxidation catalysts . These catalysts can modify a polymeric substrate that threads through one of the cages, while the properties of the substrate can be allosterically controlled, e. g. in terms of binding strength, threading speed, etc., via binding of an allosteric effector in the second cage.Future research will be directed towards providing 2(−)‐Zr(1))Deposition Number 2023416  should be addressed to the authors.SupplementaryClick here for additional data file.


Chalcogen bonds are σ hole interactions and have been used in recent years as an alternative to hydrogen bonds. In general, the electrostatic potential at the chalcogen atom and orbital delocalization effects are made responsible for the orientation of the chalcogen bond. Here, we were able to show by means of SAPT calculations that neither the induction  nor the electrostatic term is causing the spatial orientation of strong chalcogen bonds in tellurium‐containing aromatics. Instead, steric interactions (Pauli repulsion) are responsible for the orientation. Against chemical intuition the dispersion energies of the examined tellurium‐containing aromatics are far less important for the net attractive forces compared to the energies in the corresponding sulfur and selenium compounds. Our results underline the importance of often overlooked steric interactions (Pauli repulsion) in conformational control of σ hole interactions. SAPT calculations of chalcogen bonds show that neither the induction  nor the electrostatic term is causing the spatial orientation of strong chalcogen bonds in tellurium‐containing aromatics. Instead, steric interactions (Pauli repulsion) are responsible for the orientation. These results underline the importance of often overlooked steric interactions in conformational control of σ hole interactions. In recent years research in the area of chalcogen bonding2EEMe2 systems and amounts to 70–90 % of the sum of all attractive terms.[Due to fundamental theoretical investigations the principle of chalcogen bonding has been understood in terms of strength and orientation.34, 35The relative orientations of the atoms involved in a chalcogen bond are often explained by orbital mixing and/or electrostatic potential.Considering the three attractive interactions it becomes evident that tellurium‐containing compounds can form strong chalcogen bonds:Herein, we investigate by means of SAPT (symmetry‐adapted intermolecular perturbation theory) calculations the nature of strong chalcogen bonds, which are formed by tellurium‐containing aromatics and different Lewis bases. The main focus is on the question of which energy terms  mostly contribute to the formation of strong chalcogen bonds. Furthermore, a model is used to clarify which interactions are responsible for spatial orientation of chalcogen bonds.Our studies were focused on investigations of the nature of strong chalcogen bonds that exist primarily between tellurium‐containing nitrogen heterocycles and different Lewis bases.32, 331–15 the double‐hybrid density functional B2PLYP1–15 are summarized in Tables S1–S2 and Figure In order to optimize the structures of the monomers and complexes 2 a–c and 13 a,b both units are connected via two hydrogen bonds , whereas van der Waals complexes are present between two aromatic systems (in 11 a and 15 a) or between an aromatic system and tetrachloromethane (in 5 a–c) . The CCSD(T)‐calculated formation energies for the complexes with chalcogen bonds amount to values between −3.3 and −6.2 kcal mol−1 in case of sulfur‐containing compounds . For simplification in the following discussion the complexes are divided into two groups: those with weak chalcogen bonds  and those with strong chalcogen bonds (E=Te). The energies of the complexes calculated with B2PLYP, B3LYP‐D3 and B3LYP are in fact different with regard to the magnitude of the values, but the trend due to which tellurium compounds form the strongest chalcogen bonds is still present (Tables S1–2).After a look at the geometries of the complexes it can be stated that the formation of chalcogen bonds is not happening in all cases: in case of 1–15. The SAPT method yields a partitioning of the interaction energy in terms of the notions of electrostatic (EELST1), induction (EIND2=Eind2+Eexch-ind2), dispersion (EDISP2=Edisp2+Eexch-disp2) and exchange (EEXCH1) interactions.EEXCH1) is related to the Pauli repulsion which essentially describes the repulsive component of the interaction due to the overlap of the densities of the interacting units. The Pauli repulsion has been associated with steric interaction.In the next step we used the DFT‐SAPT50, 51ESAPT=EELST1+EEXCH1+EIND2+EDISP2+δHF1–15 are summarized in Tables S3 and S4. Additionally, the percentage contributions of the attractive parts (dispersion (EDISP2), induction (EIND2), electrostatic (EELST1) and δHFterm) of total attraction are depicted in Figure 5 a–c, 11 a and 15 a represents the main attraction force. In complexes with weak chalcogen bonds  the dispersion and the electrostatic term are dominant. In general, the latter is slightly larger. However, the induction term plays a subordinate role and only contributes 3–12 % to the net attractive interactions.The data of the SAPT interaction energies and the values of the individual terms for complexes ion EDISP, induct14 c  approximation) and 15 c (CCSD(T): ΔE=−20.0 kcal mol−1). The percentage of EIND2amounts to 41 % for 14 c and to 46 % for 15 c. The latter is the largest term among the attractive interactions. In all other cases of strong chalcogen bonds the electrostatic term is most dominant.A completely different picture is found for strong chalcogen bonds (E=Te). In these bonds the induction term plays a highly important role and the following trend can be observed: the higher the complex formation energy is, the higher is the percentage of induction energy contributing to the net attractive interactions. Examples underlining this statement are complexes EDISP2, the significance of dispersion energy drops from S to Te. In case of the strongest chalcogen bonds (14 c and 15 c) the dispersion energy amounts to only 15 %. This is even less than the percentage of dispersion interactions in hydrogen bonds of acetic acid dimers . A comparison with complexes 2 a–c and 13 a,b, which are formed by hydrogen bonds, is as well interesting. In these complexes the dispersion energy amounts to approximately one quarter of the overall attractive forces. This shows that the dispersion energies of strong chalcogen bonds are—with regard to the attractive forces—on a similar significance level as the dispersion energies of hydrogen bonds.Please note that the dispersion term becomes less important in strong interactions even though tellurium (which can develop extra strong dispersion interactions based on its polarizability) is the element that is involved into chalcogen bonding. Nevertheless, not only dispersion energies in chalcogen bonds increase from sulfur to tellurium but also exchange energies (Pauli repulsion) as well as induction and electrostatic terms. Due to the fact that the latter increase more from S to Te than m7 . Additionally, the planes of the aromatic rings had to be perpendicular to one another (θ=90°). To determine the origin for chalcogen bond orientation the angles α and β were varied from 80° to 140° and 90° to 180°, respectively.It is well accepted that the relative orientation of atoms being involved in chalcogen bonding can be explained by electrostatic and orbital mixing effects.35, 36m‐I7  is obtained which is very similar to the optimized geometries of 7: the nitrogen atom of the pyridine points into the area with the most positive electrostatic potential of the chalcogenazole and the n(N) → σ*(E‐R) interaction should be at its highest point in this position  is obtained in which the nitrogen atom is oriented centrally toward the chalcogenazole ring  is obtained in which the nitrogen atom is perpendicular to the chalcogenazole ring  are only slightly different to the energies of complexes 7 (ESAPT(m‐I7)‐ESAPT(7)=0.68 kcal mol−1 for S; 0.31 kcal mol−1 for Se; 0.20 kcal mol−1 for Te). Therefore, conformers I of m7 represent a legitimate model for 7. As expected, conformations II and III are most unfavorable. An analysis of the single terms of conformations I, II and III should shed light on the origin of chalcogen bond orientation.Complex formation energies and individual values of the SAPT terms are listed in Tables S5‐S7. The SAPT energies of conformers EIND2) of model system mc7 depending on the angles α and β. Due to the fact that the induction term for tellurium compounds is remarkably larger than the induction term for S and Se compounds (see above), the dependency on the angle should be most obvious. Surprisingly, the induction term only changes slightly with regard to the angles α and β  than I, the induction term is almost irrelevant for the orientation of strong chalcogen bonds. The change of dispersion energy with the angles α and β cannot explain the origin of chalcogen bond orientation in 7 c, either  NBOs and “empty” (acceptor) NBOs depending on the angles α and β were focused. Beside stabilization energies for the two n(N6) → σ*(Te1‐C2/5) interactions, the sum of all interaction energies between the two monomers showing values higher than 0.5 kcal mol−1 is shown in Figure −1, a trend should be observed. In fact, the n(N6) → σ*(Te1‐C5) interaction decreases by changing the angles α or β. It is however replaced by other donor NBOs → acceptor NBOs so that only a slight change of the sum of stabilization energies based on orbital mixing occurs.Since the induction term of the SAPT calculations is related to orbital mixing, NBO  analyses7 c, the two other terms are considered in the following. For this purpose, the electrostatic (EELST1) and exchange (EEXCH1) interactions in model systems m7 depending on the angles α and β are illustrated in Figure Due to the fact that neither the induction nor the dispersion term could explain the energy changes caused by the geometry of the chalcogen bond in I and II in Figure I to II is almost three times as high as the change of the electrostatic term and therefore the dominating part  is equipped with stronger net attractive interactions than I  and II , it can be stated that the Pauli repulsion (steric interaction) disables the formation of conformations II and III and is therefore responsible for the orientation of the strong chalcogen bond in 7 c. The analogous models mc8, mc10, mc12 and mc15 confirm the dominance of steric interactions for spatial orientation of strong chalcogen bonds in 8 c, 10 c, 12 c and 15 c (Tables S8‐S11). Please note, a transition from conformation I in model 15 mc to both conformation II and III leads to an increase of the electrostatic energy (Table S8).First, we consider the changes caused by modifying angle α  should be addressed to the authors.SupplementaryClick here for additional data file.


Herein, we combine X‐ and Q‐band EPR experiments on native and methanol‐treated PSII of Spinacia oleracea and show that methanol‐treated PSII preparations of the S3 state correspond to a previously uncharacterized high‐spin (S=6) species. This is confirmed as a major component also in intact photosynthetic membranes, coexisting with the previously known intermediate‐spin conformation (S=3). The high‐spin intermediate is assigned to a water‐unbound form, with a MnIV3 subunit interacting ferromagnetically via anisotropic exchange with a coordinatively unsaturated MnIV ion. These results resolve and define the structural heterogeneity of the S3 state, providing constraints on the S3 to S4 transition, on substrate identity and delivery pathways, and on the mechanism of O−O bond formation.Among the intermediate catalytic steps of the water‐oxidizing Mn 3) in biological water oxidation in higher plants is a mixture of a high‐spin and an intermediate‐spin form. These two forms represent distinct structural components related to water binding and activation on the path towards oxygen evolution.Electron paramagnetic resonance spectroscopy reveals that the final metastable catalytic state (S An important fact utilized in the present work is that the spectroscopic phenomenology is species‐dependent, suggesting that different components of the S3 state can be accessed more easily in specific photosynthetic organisms.Photosystem II (PSII) catalyzes the biologically fundamental reaction of light‐driven oxygen evolution from water. The active site of water oxidation, the Oxygen Evolving Complex (OEC), contains an inorganic MnS3 state,2, 3 a3 state, the composition of the latter, the details of water binding, and the conformation of the inorganic cluster that is active in dioxygen evolution. To address these questions, it is necessary to resolve distinct intermediates experimentally, which can be accomplished by slowing down S‐state transitions and enhancing distinct S‐state components. One way of achieving this is by using a water substrate analogue sufficiently small to reach the active site via physiological water channels yet sufficiently large to hinder water delivery through that channel. It should also be non‐coordinating so that the geometric and electronic structure of the OEC is not fundamentally altered. These conditions are fulfilled by methanol, which accesses the OEC of higher plants up to the terminal point of at least one water channel.[Key questions in biological water oxidation concern the precise cascade of transformations leading to the S channel.10, 11S. oleracea) PSII membranes and in spinach PSII preparations in the presence of 5 % MeOH. Our results successfully resolve a previously unidentified high‐spin (S=6)/ intermediate‐spin (S=3) heterogeneity in the S3 state. Crucially, the high‐spin component is found to represent the majority constituent of the S3 state, necessitating reappraisal of current ideas about the composition of this state and the mechanism of water oxidation. The high‐spin population is assigned to the catalytically active conformation of the OEC that is able to bind substrate water at a coordinatively unsaturated MnIV ion or possibly progress directly to the final oxygen‐evolving stage of the cycle.Here we report combined EPR studies at X‐ and Q‐band in intact spinach . However, several features centered at lower magnetic fields do not match the corresponding areas of the theoretical curve . This indicates the presence of an additional spin configuration of the S3 state that is “EPR silent” at X‐band.The Seviously.21, 223 EPR measurements at Q‐band in 5 % MeOH‐treated preparations show that the features attributed to the S=3 signal practically disappear and only one low field EPR derivative at geff≈8 is observed, that is very similar to that at the corresponding region in untreated PSII preparations  that may originate from the exchange couplings within the OEC in the S3 state, the highest possible spin of S=6 provides by far the best match for the experimental low‐field feature . The parameters of D=+1.523 cm−1 and E/D=0.14 for the S=6 configuration uniquely describe the experimental spectrum at Q‐band, since the position of the low field derivative feature is very sensitive to even small changes of the D and E/D parameters from the above values. Additionally, with the aforementioned parameters, the theoretical spectrum at X‐band presents, correctly, no EPR signal, as required by the experimental data (curves (b) of Panels A and B of Figure S=6 signal uniquely characterize the S3 state in MeOH‐treated spinach PSII.Ss Figure . The recgeff≈8 of the S3 state in both intact and MeOH‐containing PSII preparations, the EPR signal in untreated preparations that do not match the S=3 configuration can be described with spin Hamiltonian parameters quite similar to those for MeOH‐treated PSII. As shown in Panel C of Figure S=3, g=2, |D|=0.179 cm−1, E/D=0.28 and S=6, g=2, D=+1.51 cm−1, E/D=0.138 satisfactorily reproduces the complete S3 experimental spectrum at Q‐band .Owing to the close similarity of the Q‐band EPR features around S=3 and S=6 coexist physiologically in the S3 oxidation state in intact spinach PSII membranes. By taking into account the relative intensities of the S=3 and S=6 simulated curves, as well as the thermal occupation of the respective ground states S=6 and S=3 multiplets , we estimate ca. 20 % for the S=3 and 80 % for the S=6 configuration. We assign the latter to the S3 population referred to in the past as an EPR‐inactive S3 form.These observations strongly indicate that two spin configurations of S=1 by X‐band EPR spectroscopy[S=3 by Q‐band experiments,3 state. A commonly accepted geometric conformation of the OEC cluster that satisfies the spectroscopic requirements of an S=3 ground state and for all Mn centers being isotropic octahedrally coordinated MnIV ions, as indicated by electron‐electron double resonance (ELDOR) detected nuclear magnetic resonance experiments (EDNMR),2 state. Modified spectral forms of the S=3 EPR signal have been reported in cation (Ca2+/Sr2+) or anion (Cl−/I−) substituted and MeOH‐treated cyanobacterial PSII.[S=6 state described in the present work for spinach PSII is experimentally identified for the first time, despite representing apparently the majority species. Its drastically different spectroscopic properties are indicative of fundamental differences in the electronic and geometric structure of the cluster compared to the S=3 form.Integer spin state EPR signals, initially attributed to ctroscopy27, 29IV S3 conformation of the OEC that has a S=6 ground state has been reported by Retegan et al.g isomeric form of the preceding S2 state  and monomer (Mn4) manganese subunits . Therefore, the two‐spin model serves as proxy of the four‐spin system for the low‐energy spin states. Crucially, the weak effective ferromagnetic coupling is of the same magnitude as the local anisotropy of Mn4, therefore the usual simplified assumptions regarding the strong exchange limit do not apply and cannot justify the high effective D value. Previous studies of exchange coupled clusters highlighted the impact of the exchange coupling anisotropy on the splitting of spin state multiplets at zero magnetic field.[IV ions should explain the relatively large effective zero field splitting.The local zero field splitting value of the five‐coordinated Mn4(IV) ion was computedD of the S=6 multiplet, additional EPR simulations were performed by introducing anisotropic exchange interaction between the trimanganese unit with SA=9/2 and the outer five‐coordinated Mn4(IV) with SB=3/2. Figure SA=9/2 and SB=3/2 with D9/2=+0.273 cm−1, D3/2=+2.14 cm−1, (E/D)9/2=(E/D)3/2=0.14, g9/2=1.98, g3/2=1.98, xxJ=yyJ=−1.382 cm−1, zzJ=−14.036 cm−1 reproduces very well the Q‐band EPR spectrum attributed to the S=6 configuration. Small variations of spin Hamiltonian parameters reproduce the EPR spectrum almost equally well, but only under the condition of anisotropic exchange.In order to investigate the contribution of anisotropic exchange to the effective S=6 state multiplet originates both from the local second order zero field splitting terms of the Mn ions and from anisotropic exchange interactions. Therefore, the present results and analysis strongly support the water‐unbound model shown in Figure S=6 signal in the S3 state of spinach PSII.In conclusion, the effective zero field splitting of the S=3 and S=6 with specific geometric configurations of the OEC cluster has important implications for understanding the nature of the S3 state itself and the catalytic progression of water oxidation in higher plants, and possibly across oxygenic photosynthetic organisms. The results establish that in spinach PSII the majority of the S3 state exists physiologically as a mixture of water‐unbound and water‐bound conformations. This must be given serious consideration in the analysis of other experimental observations. It also calls to question the validity of “single‐component” structural interpretations derived from crystallographic studies that are so far unable to resolve state‐specific structural heterogeneity and show irregularities in the definition of the central O atom positions.[3 forms discussed here. Furthermore, the almost complete arrest of water binding in methanol‐treated samples without inhibition of Mn oxidation establishes that Mn oxidation in the S2→S3 transition strictly precedes and is completed independently from water binding. Water binding occurs at a component of the S3 state proper, that is, after reduction of the YZ. radical. This suggests that the conformation represented by the S=6 EPR signal corresponds to the S3 population formed under normal catalytic progression, disfavoring early water binding2 state.Matching the two observed EPR signals of ositions.2, 3 T2→S3 transition because they can offer a coordination site in the S2 state. Observations relating to methanol and ammonia interaction with the OEC in the S2 state support the idea that water binds externally to a 5‐coordinated Mn4 site,[13C‐ or 2H‐ labeled methanol are consistent with MeOH positioned either close to Mn4 or close to Ca2+ in the S2 stateS=6 signal to a species with a five‐coordinated Mn4 ion supports Mn4 as the site of initial water binding in the S3 state.Both Mn1 and Mn4 are discussed as possible sites of water binding in the SMn4 site,30, 36S=6 water‐unbound component to a majority S3 species in spinach PSII implies an enthalpic barrier to water binding itself, if it occurs directly at Mn4, or due to additional rearrangements and proton translocations required to form the “oxo‐hydroxo” S=3 component. The latter multi‐step pathway may involve several water‐bound forms,S=3 spin state. The identity of atoms that proceed from a water‐bound S3 form to create the O−O bond in the final catalytic transition via radical coupling[The attribution of the  coupling41, 423 state into a water‐unbound form via methanol treatment does not inhibit oxygen evolution per se, because flashing of the water‐unbound S3 state still enables progression to S0. This leaves open the question whether water binding in the S3 state is at all required for the final S3→S4 catalytic step, and hence the question which component of the S3 state is catalytically active. Krewald et al. suggested that water binding is not obligatory for final oxidation of the OEC cluster to the S4 state.IV‐oxyl group,[3 form, or a 5‐coordinated MnV‐oxo group,3 population. Further experimental studies are clearly required to resolve the intermediates of the S3→S4 transition, but the above considerations support the intriguing possibility that all productive catalytic transitions in biological water oxidation past the resting S1 state may occur physiologically via distinct configurations of the metastable heterogeneous S2 and S3 states with pre‐bound substrates, without requiring additional water binding up until dioxygen evolution and reconstitution of the S0 state  and water‐bound (S=3) forms, which so far have not been resolved by structural methods of investigation such as protein crystallography. The results confirm that Mn oxidation in the S2→S3 transition is independent of water binding. Both components of the S3 state can in principle advance to the oxygen‐evolving S4 state, therefore it is possible to formulate distinct structural and electronic configurations of the cluster that support either radical‐type or nucleophilic O‐O coupling, with fundamental consequences for understanding the nature of redox progression ‐charging versus catalysis‐ within the catalytic cycle. The intrinsic heterogeneity of the S3 state uncovered in the present work has important implications for correctly evaluating the information derived from less discriminating experimental approaches and for directing future mechanistic investigations into the most critical final S3→S4 step that leads to dioxygen evolution.The coexistence of the The authors declare no conflict of interest.As a service to our authors and readers, this journal provides supporting information supplied by the authors. Such materials are peer reviewed and may be re‐organized for online delivery, but are not copy‐edited or typeset. Technical support issues arising from supporting information (other than missing files) should be addressed to the authors.SupplementaryClick here for additional data file.


PBDT2T‐b‐N2200 shows a broad complementary absorption behavior owing to a wide‐band gap donor (PBDT2T) present as a D‐block and a narrow‐band gap acceptor (N2200) present as an A‐block. Polymer solar cells (PSCs) with conjugated block copolymer (CBCP) are fabricated using a toluene solution and PSC created with an annealed film showing the highest power conversion efficiency of 6.43%, which is 2.4 times higher than that made with an annealed blend film of PBDT2T and N2200. Compared to the blend film, the PBDT2T‐b‐N2200 film exhibits a highly improved surface and internal morphology, as well as a faster photoluminescence decay lifetime, indicating a more efficient photoinduced electron transfer. In addition, the PBDT2T‐b‐N2200 film shows high crystallinity through an effective self‐assembly of each block during thermal annealing and a predominant face‐on chain orientation favorable to a vertical‐type PSC. Moreover, the CBCP‐based PSCs exhibit an excellent shelf‐life time of over 1020 h owing to their morphological stability. From these results, a D–A block copolymer system is one of the efficient strategies to improve miscibility and morphological stability in all polymer blend systems.A highly crystalline conjugated donor (D)–acceptor (A) block copolymer  with conjugated block copolymer are fabricated using a PBDT2T‐ In particular, in terms of the CBCP structural design, the following important points should be considered. First, the DB and AB in CBCP should achieve crystallization through self‐organization among the same blocks and form a face‐on orientation, which can help with a charge carrier transport in conventional vertical PSC devices. Second, a CBCP film has a fine surface and internal morphology without a large phase separation. Third, the efficiency of the PSC can be improved if the complementary absorption range of the CBCP is broadened through a combination of DB and AB. In particular, CBCP bearing DB and AB is likely to have a high molar absorptivity within the 400–700 nm region, which shows a strong intensity in the solar spectrum. In addition, we must seriously consider the excess solvent required in the PSC manufacturing process. According to studies on highly efficient PSCs reported thus far, the most commonly used solvents and additives for preparing blend solutions for active layer deposition are all halogenated organic compounds. Therefore, in view of the mass production of PSCs, their excessive use owing to harmful effects of such halogenated compounds on humans should be suppressed.N,N′‐bis(2‐octyldodecyl)‐naphthalene‐1,4,5,8‐bis(dicarboximide)‐2,6‐diyl]‐alt‐5,5′‐} (N2200)In terms of the material design, compared to polymer donors, polymer acceptors are less developed because their energy levels are difficult to control by combining various donating and accepting moieties as monomers. Among them, poly {[b‐N2200) containing a wide‐band gap benzodithiophene‐bithiophene carboxylate donor block (PBDT2T) and a narrow‐band gap N2200‐based acceptor block. PBDT2T‐b‐N2200 can exhibit wide complementary absorption within the 300–800 nm range. The maximum PCE of a nonhalogenated solvent‐processed CBCP‐based PSC device was measured as 6.43% after thermal annealing the active layer at 160 °C, which is remarkably higher than that of the blend film. Compared to those of a binary blend film using PBDT2T and N2200, a PBDT2T‐b‐N2200 film shows a dramatically improved surface and an internal morphology. This is well matched with the time‐resolved photoluminescence (TRPL) lifetime values and the distributed lifetime images. Interestingly, the annealed PBDT2T‐b‐N2200 films showed that DB and AB are arranged in a face‐on manner with independent/associated crystallization  and easily form fine domains, achieving percolation pathways for holes and electrons. More intriguingly, the corresponding CBCP‐based PSCs exhibit a superior shelf‐life time of their photovoltaic performance of over 1020 h when stored under ambient conditions, without a significant change in morphology.In this study, we introduce a new highly crystalline conjugated D–A block copolymer (PBDT2T‐22.1b‐N2200) bearing a wide‐band gap DB (PBDT2T) and a narrow‐band gap AB (N2200) was synthesized using a one‐pot synthesis method. The expected general structure of PBDT2T‐b‐N2200 is shown in FigureA highly crystalline CBCP  capable of forming a donor block without adding an additional catalyst in the same pot. The reaction progress in polymerization is illustrated well in Figure S1 (Supporting Information).In our previous study, we synthesized a p‐type polymer using M3 and methyl 2,5‐dibromothiophene‐3‐carboxylate (3MT) units.b‐N2200 at 600–700 nm to improve the complementary absorption.Contrary to our previous CBCP bearing PBDT2T and NDI‐Se, to promote the phase separation of a blend film, NDI‐Se as an AB was replaced with N2200, which has longer branched alkyl side chains and bithiophene as a donor repeating unit in a polymer backbone. In this case, the acceptor block using M1 and M2 can be used to enhance the molar absorptivity of PBDT2T‐b‐N2200, was precipitated in methanol and a crude polymer was purified through a Soxhlet extraction using acetone, hexane, and methylene chloride. Through the purification with this extraction, PBDT2T‐b‐N2200 of a relatively low molecular weight, an unreacted donor and acceptor oligomer type monomers, and a residual palladium catalyst could be removed.We determined the appropriate molecular weight of N2200 obtained through a 40 min reaction; added M3 and M4, which reacted to form a DB from the end of N2200; and carried out a Stille coupling reaction in the presence of the previously added palladium catalyst. Luckily, this study has the advantage of confirming the progress of polymerization using the four monomers by changing the color of the solution . After 48 h, the crude product, PBDT2T‐b‐N2200 was successfully synthesized, the number average molecular weight (Mn) of the N2200 and of PBDT2T‐b‐N2200 was measured using GPC, as shown in Figure S2 (Supporting Information). The Mn value of the intermediate N2200 block and the final PBDT2T‐b‐N2200 were measured as 20.9 and 33.3 kg mol−1, with PDIs of 3.28 and 3.21, respectively. From these results, it was thought that the final product contained diblock and triblock copolymers. However, their exact composition could not be analyzed. To compare the various properties of PBDT2T‐b‐N2200 with those of the physical blend of DB and AB, PBDT2T and N2200 were also synthesized, although the MW of the two polymers did not match the MW of DB and AB present in PBDT2T‐b‐N2200 .To confirm that PBDT2T‐b‐N2200 show good solubility at room temperature (RT) in common chlorinated solvents such as chloroform, chlorobenzene, and o‐dichlorobenzene. Intriguingly, PBDT2T‐b‐N2200 is well soluble in toluene, xylenes, and mesitylene, which are nonhalogenated green solvents.The solubility of the active layer material in an organic solvent is crucial for the production of PSC through a solution process. PBDT2T, N2200, and PBDT2T‐b‐N2200 and determined the molar ratio of the PBDT2T and N2200 units in the block copolymer by measuring 1H NMR an elemental analysis (EA). As shown in Figure S3 (Supporting Information), the presence of both PBDT2T and N2200 blocks in PBDT2T‐b‐N2200 was confirmed by integration of the peak area for the PBDT2T repeating unit  and the N2200 repeating unit .We confirmed the chemical structure of PBDT2T‐b‐N2200 obtained from repeated elemental analyses because the nitrogen element only exists in the N2200 block, as shown in Table S1 (Supporting Information). Resultantly, the molar ratios of the PBDT2T and N2200 repeating units were determined around 1:1 in PBDT2T and N2200. The PBDT2T‐b‐N2200 obtained after a one‐pot synthesis may contain a small amount of individual low molecular weight DB or AB owing to defective polymerization sites, but the final product has a block copolymer structure mainly containing DB and AB.Finally, the molar ratio of the repeating units of PBDT2T and N2200 was determined using the content of nitrogen in PBDT2T‐2.2b‐N2200 used in this study are shown in Figureb‐N2200 determined using a cyclic voltammetry measurement are shown in Figure S4 (Supporting Information). The oxidation/reduction potentials of PBDT2T and PBDT2T‐b‐N2200 were observed to be +0.86/−0.6 and +1.03 V/−0.57 V, respectively. The optical band gaps (Eg) of PBDT2T and N2200 using the cutoff wavelengths of the absorption spectra in a thin film state were determined to be 1.98 and 1.47 eV, respectively. The electrochemical bandgap of PBDT2T‐b‐N2200 was calculated as 1.60 eV, which is between those of PBDT2T and N2200. As a result, the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) energy levels were determined to be −5.30/−3.32, −5.60/−3.84, and −5.47/−3.87 eV for PBDT2T, N2200, and PBDT2T‐b‐N2200, respectively. The HOMO level of PBDT2T‐b‐N2200 was observed between PBDT2T and N2200 to that of PBDT2T, whereas the LUMO level is slightly lower‐lying compared to that of N2200  were observed to show absorption bands of PBDT2T and N2200. The solution showed three absorption bands at 388, 517, and 700 nm, which are similar absorption features of PBDT2T and N2200. In a film state, PBDT2T‐b‐N2200 showed three peaks at 393, 540, and 703 nm. The as‐cast film of N2200 exhibits two distinct absorption bands, located within the ranges of 300–440 and 500–850 nm, with a maximum peak absorption observed at ≈393 and 703 nm, respectively.The UV−visible absorption spectra of the synthesized PBDT2T, N2200, and PBDT2T‐Comparing the absorption bands of N2200 in solution and film states, almost an identical absorption peak at 703 nm is shown, which might be due to a preorganization of N2200 molecules even in a solution. By contrast, the absorption band at 508 nm in a PBDT2T solution was shifted to 535 nm in a film state, which is ascribed to a high intermolecular interaction.b‐N2200 film showed a broad absorption range of 300–900 nm, which is a complementary absorption behavior aided by the presence of PBDT2T and N2200. In particular, the absorption at 600–800 nm owing to N2200 is quite helpful in providing a more efficient light harvesting property because of the overlapping with the solar emission spectrum with a high intensity. As with a PBDT2T film only, the absorption spectrum of PBDT2T in PBDT2T‐b‐N2200 was also red‐shifted in a film state, which indicates a more significant self‐association between the PBDT2T chains in a film state. From these results, no new absorption bands were observed owing to the interaction of two donor and acceptor blocks.In Figure b‐N2200 in chloroform . To suppress the intermolecular CT interaction between the polymer chains, a remarkably low concentration (≈10−5m) of PBDT2T‐b‐N2200 in chloroform was used for the steady state and transient PL experiments. Based on the experiment results, the possible CT state formation and occurrence of PL within the visible wavelength range are depicted schematically in Figure S5c (Supporting Information). As shown in Figure S5a (Supporting Information), the PBDT2T solution emits a fluorescence peak at 600 nm but no fluorescence is observed for a N2200 in a solution.To investigate the molecular charge transfer (CT) phenomenon in the block copolymer, steady state and transient photoluminescence (PL) measurements were conducted using PBDT2T and PBDT2T‐b‐N2200, it exhibits an emission peak at 596 nm. When fixing the concentration of PBDT2T in a blend solution with N2200 and PBDT2T‐b‐N2200, the decrement of the PL intensity in the PBDT2T‐b‐N2200 solution was larger than that of the blend solution. As shown in Figure S5b (Supporting Information), transient PL signals are fitted using a triexponential function, and the fitting results are summarized in Table S2 (Supporting Information). Based on our fitting results, the experiment results indicate that the average PL lifetime is shorter for PBDT2T‐b‐N2200 (τavg = 0.89 ns = 1/(k1 + kCT)) than for PBDT2T (τavg = 1.0 ns = 1/k1) by 110 ps.kCT) from DBs to ABs, the rate constant for CT state at the local DB/AB binding region in a PBDT2T‐b‐N2200 structure in chloroform can be determined as kCT = 1/τCT = 1/(8.3 ns). It has been conjectured that the photoinduced charge transfer (CT) state formation in PBDT2T‐b‐N2200 is more pronounced and efficient than the PBDT2T:N2200 blend solution. To clarify the reason for this different PL quenching behavior in a solution state, a transient PL measurement was accurately conducted.For a very diluted solution of PBDT2T‐2.4b‐N2200 film as the active layers, we fabricated inverted‐type PSCs with a configuration of ITO/ZnO/active layer/MoO3/Ag  curves and the corresponding EQE spectra are displayed in Figure The b‐N2200 film exhibited a PCEmax of 4.54% with a Jsc of 11.63 mA cm−2, a Voc of 0.83 V, and an FF of 0.47. When the active layer was annealed at 160 °C for 10 min, Jsc increased to 12.21 mA cm−2 and FF reached 0.62, resulting in 6.43% PCE. A more detailed analysis with the annealing temperature is displayed in Figure S6 and Table S3 (Supporting Information). We also found that the PSCs fabricated using the annealed PBDT2T‐b‐N2200 films from several devices exhibits an excellent reproducibility of PCE . In addition, the polymers obtained from three different batches did not display significant difference, as shown in Figure S8 and Table S4 (Supporting Information). All‐PSCs made of blend films showed a relatively poor PCE of 2.0–2.6% with low Jsc values in as‐cast and annealed devices. The large difference in Jsc between PBDT2T‐b‐N2200‐ and PBDT2T:N2200 blend‐based PSC devices were confirmed through EQE measurements , compared to that of the annealed blend‐film‐based PSC device. It indicates that the PBDT2T‐b‐N2200 thin film exhibits enhanced light harvesting after annealing at 160 °C, resulting in relatively high scJ = 12.21 mA cm−2 and PCE = 6.43%. This may be attributed to the unique crystallization characteristics of the PBDT2T‐b‐N2200 film annealed at 160 °C, which is discussed in more detail in the grazing incidence wide‐angle X‐ray diffraction (GIWAXD) analysis of the polymer film.The as‐cast PBDT2T‐Rs) and shunt resistance (Rsh) values for the four different devices are summarized in Table Rs and an increasing tendency for Rsh. In particular, the FF value of the PSC with an annealed PBDT2T‐b‐N2200 film is influenced greatly by both Rs (7.63 Ω cm2) and Rsh (950 Ω cm2), and a larger FF value results in improved performance of the PSC.b‐N2200 exhibited an FF of ≈0.47, whereas the device using the film that was annealed at 160 °C for 10 min exhibited an FF of ≈0.62. This is consistent with the smaller value of Rsh (360 Ω cm2) of the as‐cast film shown in Table The series resistance (Jph) on the effective voltage (Veff) of the device  of the devices characterized herein. Here, Jph can be defined as Jph = JL − JD, where JL and JD are the current densities under illumination and in the dark, respectively. In addition, Veff can be defined as Veff = V0 – Vbias, where V0 is the voltage at which Jph is zero and Vbias is the applied external voltage bias.Veff values, mobile charge carriers rapidly move toward the corresponding electrodes with a minimal recombination.We also studied the charge generation and extraction properties of the CBCP‐based PSC devices to understand the main mechanisms related to their superior performance as compared to that of the blend‐film‐based PSC. To investigate the charge generation, dissociation, and extraction properties, we measured the dependence of the photocurrent density (Gmax) can be estimated from the equation Jsat = q·L·Gmax, where Jsat is the saturated photocurrent density, q is the electronic charge, and L is the thickness of the active layer in the devices. The calculated Gmax values of the devices are summarized in Table S5 (Supporting Information). The annealed PBDT2T‐b‐N2200 and blend‐film‐based device showed a saturation in the Jph value, indicating that all photogenerated charge carriers are extracted by the electrodes. The device with an annealed PBDT2T‐b‐N2200 film showed the highest Gmax value (8.31 × 1027 m−3 s−1), which was much higher than the calculated Gmax values for a PBDT2T:N2200 annealed blend film device (3.1 × 1027 m−3 s−1). These findings indicate that the exciton generation of the PBDT2T‐b‐N2200 is faster than that of the PBDT2T:N2200 blend film device, which agrees with the corresponding higher Jsc values.The maximum exciton generation rates . The data were fitted to the power‐law equation, Jsc ∝ Plightα. We also measured Jsc versus the light intensity (Plight) to study the charge‐recombination behavior α.b‐N2200 film‐based PSCs is 0.995, indicating that the molecular recombination is effectively diminished, whereas the PBDT2T:N2200 annealed blend‐film‐based device exhibits a slightly higher degree of bimolecular recombination with an α value of 0.964.To investigate the extent of the carrier recombination in the active layers of the PBDT2T:N2200 blend and the PBDT2T‐r Figure e. The rep‐xylene, and mesitylene. In addition, we fabricated a device using CB as a control for comparison with the MB device. The detailed photovoltaic data obtained from the PSCs are shown in Figure S11 and Table S6 (Supporting Information). As a result of the device using CB, the thermal annealed PBDT2T‐b‐N2200 film exhibited a PCEmax of 5.38% with a Jsc of 11.81 mA cm−2, a Voc of 0.86 V, and an FF of 0.53. Contrary to the CB solution processed PSC, the devices prepared with MB solvents displayed a slightly higher PCE exceeding 6.0%. The devices showed a similar performance after thermal annealing of the active layer. The device derived from the toluene solution showed the best performance with the highest PCE of 6.43%. This is one of the highest PCE values obtained from CBCP‐based PSCs processed using nonhalogenated solvents achieved thus far.To investigate the feasibility of using nonhalogenated solvents in solution processing for CBCP‐based PSCs, we fabricated the devices using various methylbenzenes (MBs) such as toluene, 2.5b‐N2200 films. PL quenching experiments were carried out to confirm the exciton dissociation and charge transfer behavior during the film states.The photovoltaic properties of the blend films observed above are closely related to the photoinduced electron transfer phenomenon. This phenomenon can be discussed by observing the PL spectroscopy of the PBDT2T, PBDT2T:N2200 blend, and PBDT2T‐b‐N2200 displayed the most effective PL quenching, with an alleviation of 98.4% of the initial emission intensity, as shown in the steady state PL spectrum shown in Figure–108 ps as the fast decay lifetimes, and 515 and 325–355 ps as the slow decay lifetimes, respectively. Intriguingly, in the case of a PBDT2T‐b‐N2200 film, a bi‐exponential PL decay was observed in which a fast decay component with a lifetime of 71 ps was followed by a slow decay component with a lifetime of 323 ps. The TRPL signal in the PBDT2T‐b‐N2200 film (τavg = 71 ps) decays much faster than that in the blend (τavg = 119 ps) and PBDT2T (τavg = 242 ps) films, as shown in Figure b‐N2200 film with fine morphology strongly contributes to the effective fluorescence quenching. From the lifetimes obtained, the PL quenching efficiencies were determined (see Table S7 in the Supporting Information), which are consistent with the trend qualitatively observed in the steady‐state PL spectra. In addition to the shortest lifetime found in the PBDT2T‐b‐N2200 film, a PL quenching efficiency of 71% is larger than that of the PBDT2T:N2200 blend film (51%).Compared to that of the blend film, PBDT2T‐b‐N2200 film would cause a sufficient exciton dissociation, leading to a high EQE and Jsc of the PSCs. In addition, Figure b‐N2200 films. When the blend and PBDT2T‐b‐N2200 films were annealed at 160 °C for 10 min, the TRPL lifetime and its uniformity in the measurement area (15 µm × 15 µm) can be observed by referring to the scale bar on the right side of the image. These images clearly reveal the uniformity of the CT domains by virtue of the color difference through the fluorescence lifetime. The blend film showed some dark spots and a nonuniform lifetime mapping on the film. These images with various colors show that PBDT2T and N2200 domains are not mixed well, and dark spots are likely to be N2200 domains that do not emit fluorescence under excitation at 535 nm. However, the lifetime distribution in a PBDT2T‐b‐N2200 film is extremely uniform compared to the case of the blend film, which is a good experiment result visually confirming that it has a short PL lifetime and nanosized phase formation. Therefore, the lifetime mapping techniques used in these small areas can be considered an important tool to determine the likelihood of thin films representing a photovoltaic performance .The average exciton lifetimes correlate well with the observed quantum efficiencies, that is, the high PL quenching in the PBDT2T‐2.6µh) and electron (µe) mobilities using hole‐ and electron‐only devices, with the configurations of ITO/PEDOT:PSS/active layer/Au and ITO/ZnO/active layer/LiF/Al, respectively. The charge mobility of the active layer of the PSC was carefully evaluated using the space charge limiting current (SCLC) method. Using the modified Mott–Gurney equations, we determined the hole and electron carrier mobility by fitting the J–V curve in the near quadratic region.J–V characteristics are shown in Figure S13 (Supporting Information).To understand the influence of the charge transport capability on the photovoltaic performance, we measured the hole  values of 3.059 and 0.546 nm, respectively. After thermal annealing, the Rq values of the PBDT2T:N2200 blend and PBDT2T‐b‐N2200 films reached 2.096 and 0.565 nm, respectively . As shown in Figure S14 (Supporting Information), the thermally annealed PBDT2T and N2200 films display distinct (100) peaks at xyq = 0.29 Å−1 (d(100) = 21.34 Å) and 0.24 Å−1 (d(100) = 25.81 Å) along the in‐plane direction, and (010) peaks at zq = 1.69 Å−1 (d(010) = 3.70 Å) and 1.60 Å−1 (d(010) = 3.92 Å) along the out‐of‐plane direction, respectively.Grazing incidence wide‐angle X‐ray diffraction was used to study the polymer chain orientation and molecular packing of a PBDT2T:N2200 blend and PBDT2T‐xyq = 0.59 and 0.89 Å−1 as the annealing temperature increases. Diffraction patterns of N2200 in an in‐plane profile displayed (100), (200), and (300) diffraction peaks, and the intensity of the (300) peak increased significantly with an increase in the annealing temperature. Intriguingly, (001) and (002) diffraction peaks  showed a decrease in intensity with the annealing temperature, which indicates that a slight molecular rearrangement can occur to plausibly realize a face‐on orientation. The as‐cast and annealed blend film displayed most of the diffraction peaks observed, as shown in the PBDT2T and N2200 films.In Figure S14 (Supporting Information), we can trace the variation of the diffraction patterns with the annealing temperature. PBDT2T showed a high increment of diffraction intensity at b‐N2200 film with the annealing temperature , (001), and (200) peaks at xyq = 0.25, 0.45, and 0.48 Å−1 along the in‐plane direction and one (010) peak at zq = 1.65 Å−1 along the out‐of‐plane direction, respectively  diffraction was revealed using GIWAXD (010) diffraction peaks and calculated using the Scherrer equation.b‐N2200 film, the donor and acceptor blocks underwent double‐crystallization behavior as confirmed through the appearance of the diffraction peaks of PBDT2T and N2200 in the diffraction profiles of the PBDT2T‐b‐N2200 films; in addition, the face‐on crystalline orientation of the polymer chains and their aggregates is thought to be the most favorable orientation to bring about an intra/intermolecular facile exciton dissociation, efficient hole/electron generation, and charge carrier transport in the PSCs.Consequently, in the PBDT2T‐From these results, it can be said that the working mechanism of the CBCP‐based PSC is almost similar to that of the conventional BHJ PSC device with a common binary blend. Charge transport pathways can only be formed when crystalline–crystalline domains with the same donor or acceptor blocks are formed in the CBCP. Although co‐crystallization between donor blocks and acceptor blocks is possible, the individual crystallization between homogeneous blocks  can provide a very beneficial effect on device performance.2.9J–V measurements under ambient conditions according to the method recommended by the ISOS‐D‐1 (shelf) protocol.We investigated the stability of the PSC device by storing it under atmospheric conditions for up to 1020 h without encapsulation. The stability of the PSC device was assessed using Figureb‐N2200 active layer. The changes in the representative Voc, Jsc, FF, and PCE values were determined with respect to the storage time under ambient conditions to clearly show the effect of aging on the photovoltaic parameters of the PSC during long‐term storage. After a maximum storage time of 1020 h, 90.1% of the initial PCE was maintained for the CBCP‐based PSC, whereas the blend‐film‐based devices maintained 59.5% of the initial PCE.b‐N2200 films under storage in ambient conditions over a long period of time, as shown in Figure –f. The PBDT2T‐b‐N2200 annealed film was observed to maintain a relatively nanosized morphology even after 1020 h under ambient conditions. However, in the case of the blend film of PBDT2T and N2200, a relatively large extent of aggregation occurs, as confirmed through the AFM images . As can be seen from the morphology of the PBDT2T‐b‐N2200 film, an excellent shelf‐life stability was observed in the PSC when using the CBCP‐based active layer.Furthermore, to investigate the effect of changes in the surface morphology on the shelf‐life, we used AFM to observe the topographical changes in the blend and PBDT2T‐3b‐N2200) showing high crystallinity and wide complementary absorption behavior for application to PSC devices. The large phase separation observed in the blend film of a donor polymer and an acceptor polymer was significantly improved using the block copolymer framework. The DB and AB of PBDT2T‐b‐N2200 showed a high crystallinity between the same blocks through a self‐assembly and improved the crystallinity through thermal annealing. Further, in the annealed PBDT2T‐b‐N2200 film, the polymer chains were remarkably observed in a face‐on orientation.In this study, we demonstrated a novel fully conjugated D–A block copolymer (PBDT2T‐For the CBCP‐based PSC prepared by annealing an active layer prepared from the nonhalogenated solvent proposed in this study, the highest PCE of 6.43% was shown, which is the highest value reported thus far among all devices including the active layer produced by conjugated block copolymers. In addition, the high efficiency PSC used in this study demonstrated an excellent shelf‐life even after 1020 h of aging owing to the morphological stability of the CBCP‐based active layer.The authors declare no conflict of interest.Supporting InformationClick here for additional data file.


G6PD gene is highly polymorphic, and over 200 mutations have been identified, many of which are associated with hemolytic anemia. Here, we analyzed the clinical genetics data of a Chinese girl with favism who developed acute hemolytic anemia after fava bean ingestion.Glucose‐6‐phosphate dehydrogenase (G6PD) deficiency is the most common human enzymopathy. The human G6PD gene exons were sequenced in the proband and her family.The clinical genetics data of the proband who developed acute hemolytic anemia were collected and analyzed, and G6PD gene variant in a Chinese girl, which we named “G6PD Wuhan.” This variant is localized exon 3 of the G6PD gene at genomic position 141G > C, that is a change from p.Lys47 to Asn. The bioinformatics analysis and protein modeling study indicated this variant may have negative effects on the enzyme activity of G6PD.We reported for the first time a novel G6PD. The variant in G6PD has implications for genetic counseling and could provide insights into the functional roles of G6PD mutations.Our results indicated that favism in the proband was caused by this novel heterozygous variant (c.141G > C) in  G6PD gene may have negative effects on the enzyme activity of G6PD.A novel variant (c.141G > C) in the exons of the  It plays a key role in protecting cells against oxidative stress by regulating the level of reduced glutathione.G6PD gene is located in the X chromosome (Xq28) and includes 13 exons and 12 introns, spanning approximately 18.5 kb.G6PD variants have been discovered based on biochemical diagnosis, among which 217 G6PD mutations have been identified at the DNA level.The G6PD gene in a 2.4‐year‐old girl with favism. Structural analysis and the potential effects of this variant on the enzyme structure or activity were also analyzed using in silico tools.In the present case, the clinical genetics data of a family with G6PD deficiency were collected and analyzed. In this family, we identified a novel variant in 22.1A 2.4‐year‐old girl with acute hemolytic anemia was referred to Wuhan Children's Hospital, and the patient was diagnosed with favism when she suffered a hemolysis crisis with severe anemia after ingesting fava beans. The biochemical and blood markers were assayed. The patient and her parents were included in the study.2.2This study was approved by the Ethics Committee of the human subjects at “Wuhan Children's Hospital.” Informed consent for molecular and biochemical studies was obtained from the patient's parents before collecting blood samples. The proband and her parents are all Han Chinese from Hubei Province, China.2.3 > 1.0; G6PD/6PGD < 1.00 was identified as a deficient activity.Enzyme activity measurement was performed 6 months after acute hemolytic anemia episode to ensure the assessment would be at a steady‐state representation of G6PD activity. The G6PD activity was performed on the proband and her parents. The analysis for G6PD deficiency was performed using the specific G6PD mensuration reagent kit , and the enzyme activity was expressed as the ratio of G6PD/6PGD. The normal G6PD enzyme activity was recognized as G6PD/6PGD2.4G6PD gene was performed using the Sanger method with the ABI PRISM® 3130 automated capillary sequencer as previously described.Genomic DNA was collected from peripheral blood leukocytes using the QIAamp DNA Blood Mini Kit  according to the manufacturer's instructions. DNA sequencing of the 12 coding exons and intronic flanking regions of the 2.5The potential effect of this mutation on the enzyme structure was analyzed using Sorting Intolerant From Tolerant (SIFT) and MutationTaster. For structural analysis, the X‐ray structure of G6PD deposited in the Protein Data Bank was applied (PDB code 2BHL and 2BH9), and a p.Asn47 mutated protein model was created with SWISS‐MODEL and visualized using Swiss PDB Viewer.3The data of G6PD activity and hematological profile of the patient are described in Table G6PD gene of the proband showed a heterozygous novel DNA variant c.141G > C (NM_001042351.2), which was inherited from her father  Figure . The nucG6PD variant (c.141G > C), had a hemolytic crisis after eating fava beans; however, her father (hemizygous G6PD‐deficient) with lower G6PD activity do not develop symptoms.Most G6PD‐deficient patients are usually asymptomatic; however, when exposed to situations , G6PD‐deficient patients can develop acute hemolytic anemia. As the previous reports, there was also a strongly dose‐dependent manner between favism and fava bean consumption in patients with G6PD deficiency. Corresponding, acute hemolytic anemia from eating fava beans (favism) appears to much more common and more severe in children than adults.4G6PD gene was pathogenic variant in this G6PD deficiency family and could be classified as Class III (WHO classification). Our data could expand the clinical and genetic spectrum associated with G6PD deficiency. Finally, we named the c.141G > C variant as “G6PD Wuhan” based on the place of birth of the proband. This novel variant could be considered for a better comprehension of biology and molecular epidemiology of G6PD deficiency.In this study, we describe a novel G6PD DNA variant  in a Chinese girl with favism. This variant was located close to the G6PD coenzyme‐binding domain. Structural modeling demonstrated that the p.Lys47Asn variant could induce the change in interaction between the amino acid residues and then alter the normal G6PD protein structure. Combined with the clinical phenotype of the patient, our study demonstrated that the variant c.141G > C in The authors declare that they have no conflicts of interest.This study was approved according to the guidelines of the Committee on the Use of Human Subjects in Wuhan Children's Hospital.


A dramatic piezochromism is found with the increase in pressure. Optical absorption spectra reveal the pressure‐induced red‐shift in bandgap with two distinct anomalies at 6.57 and 11.18 GPa, and the energy tunability reaches 360 meV within 20.02 GPa. Combined with structural characterizations, Raman and infrared spectra, and theoretical calculations using density functional theory, results reveal that, the first anomaly is caused by the formation of a Br‐Br bond among the [SeBr6]2− octahedra, and the latter is attributed to a cubic‐to‐tetragonal phase transition. These results provide a clear correlation between the chemical bonding and optical properties of (NH4)2SeBr6. It is believed that the proposed strategy paves the way to optimize the optoelectronic properties of HDPs and further stimulate the development of next‐generation clear energy based on HDPs solar cells.Lead‐free halide double perovskites (HDPs) are promising candidates for high‐performance solar cells because of their environmentally‐friendly property and chemical stability in air. The power conversion efficiency of HDPs‐based solar cells needs to be further improved before their commercialization in the market. It requires a thoughtful understanding of the correlation between their specific structure and property. Here, the structural and optical properties of an important HDP‐based (NH 4)2SeBr6 is strongly correlated with the re‐organization of Br‐Br bonds and the rotation and distortion of [SeBr6]2− octahedra. The structure–optical property relationship constructed here is a straightforward approach to optimize the optoelectronic properties of halide double perovskites (HDPs) and further stimulate the development of next‐generation clear energy based on HDPs solar cells.Pressure‐induced optical properties variation of lead‐free halide double perovskite (NH Based on such approach, various relatively more stable and nontoxic HDP materials have been proposed.Organic–inorganic lead (Pb) halide perovskite solar cells have attracted a tremendous amount of attentions because of their remarkable power conversion efficiency (PCE), which has increased from 3.8% in 2009 to 25.2% in 2019.2BX6 HDP structure, which is characterized by isolated [BX6]2− octahedral units bridged with A‐site cations, is in contrast to the corner‐sharing arrangement of the ABX3 perovskite species. Associated with this structural change, Cs2SnI6 is reported to exhibit higher stability than CsSnI3 because of its stronger Sn‐I bonding due to the shortened Sn‐I bond lengths in the [SnI6]2− octahedral units. As a consequence, such a bonding change within the octahedral units significantly affected the boundary conditions of electronic wave functions and led to the reduced bandgap of the former as compared with the latter.+ cation on the A site with an organic ligand such as NH4+ or CH3NH3+. Specifically, the electronic structure can be effectively modified via coupling the ligands to the rotational dynamics of [BX6]2− octahedral units through the enhanced hydrogen‐bonding interactions with the surrounding X‐site framework.4)2SeBr6 is a typical HDP material that is capable of tuning chemical and physical properties by modifying its structure, and thus it is needed to be investigated further.The A2)2PbBr3, and found that its structure undergoes two phase transitions below 2.2 GPa, directly leading to the red shift/blue shift of bandgap and the variation of the colors.2)2PbI3 is reported to experience a red shift from 1.489 to 1.337 eV, which exactly reaches to the optimal bandgap required by Shockley–Queisser efficiency limit.3NH3SnI3 can possess structural stability, increased electrical conductivity, and enhanced photo responsiveness via two sequential compression and decompression cycles.2BX6 HDPs by introducing pressure. Moreover, these high‐pressure effects of structural modifications on the bandgap of HDPs can be reproduced by chemical‐pressure and/or the strain induced by a substrate on thin films for photovoltaic applications.Pressure is a controllable and predictable way that is extensively used to precisely tune the properties of various materials.4)2SeBr6. Dramatic piezochromism varying from initial light‐yellow to red optical absorption spectra reveal the pressure‐induced red‐shift in the bandgap with two distinct anomalies at 6.57 and 11.18 GPa and the energy tunability ranges up to 360 meV within 20.02 GPa. DFT calculations further convincingly reveal that, the first anomaly is caused by the formation of Br‐Br bonds of the inter‐[SeBr6]2‐ octahedra; and the latter is attributed to a cubic‐to‐tetragonal phase transition with the rotation and distortion of [SeBr6]2− octahedra driven by the pressure, which is accompanied with lifting of the degeneracy of the Se‐Br bonds in the aid of hydrogen bonding. The present findings not only establish the underlying microspectroscopic mechanism of the pressure effect on tuning the specific atomic structure and thus the optical properties of (NH4)2SeBr6 at high pressure, but are also expected to present a straightforward approach for the design of new HDPs with superior properties and offer the possibility of new opportunities and strategies for practical photovoltaic applications.Here, we adopted symmetric diamond anvil cell high pressure techniques, including UV‐vis absorption, in situ angle‐dispersive X‐ray diffraction (ADXRD), Raman and IR measurements, as well as density functional theory (DFT) calculations to map the pressure effect on the structure‐property relationship of an important HDP‐based (NH24)2SeBr6, which could shed light on understanding the electronic structure and characteristic of the bandgaps. Under ambient conditions, (NH4)2SeBr6 displays light yellow color. With increased pressure, we observe piezochromism as manifested in the color changes, i.e., the light‐yellow color gradually changes to red up to 20.24 GPa 2SeBr6 is estimated to 2.12 eV under ambient conditions 2SeBr6. During this pressure range, the bandgap narrows about 360 meV in the visible spectrum within 20.02 GPa. The sensitivity of bandgap of this material under pressure would provide an applicable strategy for the fabrication of (NH4)2SeBr6‐based sensor and switcher devices. Moreover, the change in the bandgap as a function of pressure presents two turning points at 6.57 and 11.18 GPa, respectively, as shown in Figure 4)2SeBr6 can be achieved by the application of pressure, which could further optimize its performance in solar energy conversion application.First, we investigate the pressure effects on the optical properties of 2SeBr6 samples obtained at various pressures during compression of up to 32.14 GPa and decompression. The XRD pattern under ambient condition reveals that the initial crystal structure is the pure cubic phase with space group Fm‐3m. The cubic structure of (NH4)2SeBr6 crystal is used as a starting pattern, and the refinement results in cell parameter a = 10.4826 Å 2SeBr6 undergoes a symmetry‐breaking phase transition at 11.20 GPa. Additional splitting of the Se‐Br bending and stretching modes are also observed in Raman spectra at 11.05 GPa , directly supporting the phase transition of (NH4)2SeBr6 from high‐symmetry to low‐symmetry structure.6]2− octahedra due to the hydrogen bond interaction. Figure 4)2SeBr6 crystal at 14.26 GPa, and a tetragonal with space group P42 is used to fit the split diffraction peaks. The structural analysis shows that the phase transition corresponds to two bond lengths for (NH4)2SeBr6, and an angle rotation for the [SeBr6]2− inorganic octahedra relative to the cubic axes. Namely, the structural phase transition from cubic to tetragonal phase is characterized by the rotation and distortion of [SeBr6]2− octahedra. With the pressure increasing, the XRD peaks subsequently shift toward higher angles and become slightly broader. After complete pressure releases, the phase transition observed is reversible, as evidenced by the return of the diffraction pattern to its initial states. And the flexible organic cations NH4+ serve as templates in [SeBr6]2− octahedral frameworks are responsible for the structural memory effect in reversible pressure‐induced phase transition.Structural variation is believed to be responsible for the intriguing color changes and the bandgap shifts. Å Figure ‐c.22 As 4)2SeBr6 as a function of pressure is plotted, as shown in FigureB0 = 22.28 GPa for the cubic phase and B0′ = 131.91 GPa for the tetragonal phase. These values are estimated by utilizing the third‐order Birch–Murnaghan equation of state.4)2SeBr6, which may be propitious to enhance the stability of solar cells. As shown in Figure a, c). Specifically, the tetragonal (NH4)2SeBr6 shows an anisotropic compressibility with its c parameter appearing more compressible than a and b in the ab plane. These behaviors reveal that the phase transition is a first‐order type, and the rotation of the [SeBr6]2− octahedra is responsible for the phase transformation of (NH4)2SeBr6 under pressure.To further obtain insights on the structural phase transition, the variation of the lattice parameters and unit‐cell volume of 2SeBr6 changes from being indirect (Γ–L) to indirect (Γ–M) with the phase transformation from cubic to tetragonal, as shown in Figure p states which hybridize slightly with the Se 4s states, while the conduction band minimum (CBM) is characterized as the antibonding hybrid state of the Se 4p and Br 4p orbitals. When pressure is applied to the cubic phase of (NH4)2SeBr6, the [SeBr6]2− octahedra are contracted and the bond length of Se‐Br decreases. As a result, CBM elevates to higher energy regime under pressure due to its antibonding characteristics. Meanwhile, the overlap between nonbonding Br p orbitals increases, resulting in a large broadening of the highest valence band. Given the stiffness of the octahedra, the Se‐Br bond is considerably stronger than the Br‐Br bond either on the surface of the octahedra (named as intra‐octahedra Br‐Br bond) or between the isolated octahedra (named as inter‐octahedra Br‐Br bond). Hence, VBM rises up greater that of the CBM, and consequently the bandgap is narrowed 2SeBr6. As shown in Figure6]2− octahedra, i.e., the rotation of the [SeBr6]2− octahedra is accompanied with a distortion of the [SeBr6]2‐ octahedra, which is responsible for the phase transformation of (NH4)2SeBr6 under pressure. Figure 6]2− octahedra as the octahedra elongate slightly in the c direction. Moreover, the inter‐octahedral Br‐Br bond lengths are changed to three cases, due to the rotation and distortion of the [SeBr6]2− octahedra. For these three cases of Br‐Br bonds, one lies in the (001) surface, and the other two are the tilt Br‐Br bonds linking the isolated octahedra. Interestingly, we find that a crossover exists between the intra‐ and inter‐octahedral Br‐Br bond lengths in the cubic phase under about 3.50 GPa. The pressure‐induced bond length variation matches well with the discontinuity bandgap in Figure Now, we discuss the pressure‐induced Br‐Br bond evaluation in (NH4)2SeBr6. This cross point matches well with the first discontinuity bandgap presented in Figure 6]2− octahedra units are rotated and distorted. As a consequence, cubic‐to‐tetragonal phase transition occurs. Meanwhile, in such phase transition process, the symmetry breaking of the [SeBr6]2− octahedral units as manifested by the tilting and elongation can further reduce the density of states by the Fermi surface and thus lower the total energy. This transition point matches well with the second discontinuity in the bandgap reduction. The above findings are further validated by charge density analysis. In Figure 4)2SeBr6 is strongly correlated with the re‐organization of Br‐Br bonds under pressure. These findings are expected to present a straightforward approach in optimizing the optoelectronic properties of related HDPs.To show the change in the bond length evolution more clearly, schematic illustrations of the neighboring Br‐Br bonds in cubic phase (1 atm and mild pressure), and tetragonal phase (high pressure) are presented in Figure 34)2SeBr6. We found a dramatic piezochromism varying from initial light‐yellow to red as increasing the degree of lattice distortion by pressure. Our combined experiments and DFT calculations establish that the re‐organization of Br‐Br bonds and the rotation and distortion of [SeBr6]2− octahedra are responsible for the bandgap anomalies at 6.57 and 11.18 GPa. These results provide a clear correlation between the chemical bonding and optical properties of (NH4)2SeBr6, and the universal role of structure induced bandgap alignment should be applied to other HDPs and further to understand, control, and design new HDPs and highlight their potential application for photovoltaic devices.In summary, we establish the microspectroscopic mechanism of the pressure induced structural evolution and optical optimization of HDP‐based (NHThe authors declare no conflict of interest.Supporting InformationClick here for additional data file.