The best photooxidation efficiencies are achieved at 9, 10, and 21 base intervals, which coincides with the pitch of 10.5 base pairs per turn in a DNA duplex. The low efficiencies for near and far guanines are due to quenching of the biphenyl by guanine and dilution of 1O2 by diffusion, respectively. The 1O2-diffusion mapping along DNA duplex provides clues to the development of efficient and selective photosensitizer agents for nucleic acid-targeting photodynamic therapy, as well as an experimental demonstration of diffusion of a particle along cylindrical surface in molecular level.To realize nucleic acid-targeting photodynamic therapy, a photosensitizer should be attached at the optimal position on a complementary oligonucleotide, where a guanine photooxidation is maximized. Here we show the photooxidation of 22 DNA duplexes with varied lengths between a  More recent studies have shown that DNA oxidation can trigger epigenetic-like gene regulations8. Furthermore, photosensitized oxidation of DNA or RNA has been suggested to be one of cytotoxic mechanisms in photodynamic therapy (PDT)10. Accordingly, understanding of nucleic acid oxidation is becoming more and more important to decipher diseases and develop pharmaceuticals.There is increasing interest in nucleic acid oxidation because it can cause cancer, aging and many diseases13 with reactive oxygen species (ROSs) including hydroxyl radical (HO•), carbonate radical anion (CO3•-), and hydrogen peroxide (H2O2) or by singlet oxygen (1O2) oxidation (type II)15, since G has the lowest oxidation potential in a nucleic acid molecule17.In the photooxidation of nucleic acids, guanine (G) is the most reactive part, oxidized by one-electron oxidation (type I)21 and even 1.2-μm charge migration has been recorded for a DNA-mediated charge transport between repair proteins22. In addition, H2O2 produced in type I oxidation is stable enough to diffuse to neighboring cells, in which it can be converted into more cytotoxic HO• or CO3•- by metal ions.23 Therefore, type I oxidation of nucleic acid has a concern of indiscriminateness in terms of both base and target cell selectivities, when one aims for PDT.In type I oxidation of DNA, charge migration through the array of π-stacked bases enables the oxidation of 5’-GG-3’ at a distance of about 20 nm far from the initial one-electron oxidation point1O2 produced in type II oxidation has a relatively short lifetime25 in cells (τ1/2 ≈ 3 μs) and thus is mostly trapped in the cell in which it originated23. As opposed to type I oxidation, however, there was little information regarding how far and well 1O2 can reach and react with G along a DNA duplex after departing from a point it is released near the strand. We can only assume that the type II oxidation of G by 1O2 is much slower than that by type I oxidation26 and thus a 1O2-producing photosensitizer should be located as close to G as possible. In this regard, the conjugates of oligonucleotides (ONs) with photosensitizers have been synthesized and photooxidation of their duplexes or triplexes with DNA examined33. But in all cases, a relatively large photosensitizer, such as chlorin29, was linked to the 3' or 5' end of ON via a relatively long linker, which would let the photosensitizers sway in the bulk water far from the target base, resulting in poor resolution of selectivity in the G photooxidation both intra- and intermolecularly. Another problem is that many photosensitizers claimed as being type II have more or less type-I characteristics35, making the selectivity data less informative about 1O2 travelling along DNA. Therefore, neither precise nor detailed information about appropriate distance between G and a photosensitizer in 1O2 oxidation and 1O2 trajectory thereof have been obtained.On the other hand, 1O2 (ΦΔ: 0.88) without generating reactive radicals and is much smaller in size than the previous photosensitizers37. If BP is linked at an appropriate position in ON with a short linker, the small BP molecule would be accommodated in or near the major groove in its duplex with DNA, restricting the departing point of 1O2 in a relatively small area and thus increasing resolution of G-oxidation selectivity. In this study, we explored the correlation between G-photooxidation efficiency and the G-to-BP distance in the duplexes of the BP-ON conjugates with DNAs. This study would provide the information about the traveling behavior of 1O2 along DNA duplexes in more detail than ever, thereby offering clues to overcome the low reactivity of type-II photooxidation of ON in a DNA- and/or RNA-targeting PDT by attaching BP at the most appropriate position of ON, where the target G would be most efficiently and selectively oxidized. In addition, the study could be a unique experimental demonstration of the diffusion of a particle along a cylindrical surface in molecular level, which is a challenging subject in diffusion science38.The authors have developed a type II biphenyl (BP) sensitizer that exclusively produces In designing BP-ON conjugates, we decided to attach the BP part at the α-methyl of thymine (T) through a freely rotatable ethylene spacer as depicted as P in Fig. 40. We defined n as the number of base intervals from P to cytidine (C) in 3’ directions of ON1, ON2, and ON3. Thus ON1[n]s with n = − 1, − 5, − 9, − 13, and − 17, ON2[n]s with n =  + 1 to + 11, + 13, + 15, + 17, and + 19, and ON3[n]s with + 21 and + 23 were synthesized (see Supplementary for details). The synthesized ONs were purified by HPLC and subjected to duplex formation with purchased ONs  to give the double strand DNAs . dsDNA5[+ 10] and dsDNA6 were prepared to study the intermolecular cross-talk photooxidation, in which inosine (I) was incorporated instead of G in dsDNA5[+ 10] to avoid intramolecular photooxidation.P was incorporated in ONs  so that the extent of separation between P and G covers two pitches of 10.5 base pairs per turn in both axial directions of B-DNA helices  of BP-T mono-nucleoside by photoirradiation at 346 nm was determined to be 0.29 in DMF 36 is probably due to non-radiative quenching by collision with the N–H bond or photoelectron transfer quenching by the N atoms in T. Even so, the 1O2-producing efficiency was sufficient for the current study.The Tm measurements were performed to verify that the addition of BP had no adverse effects on duplex formation. As a result, the melting values (51–55 °C) were the same as or slightly higher than that of the corresponding natural dsDNA (51 °C) for all the tested dsDNA1[n]s and dsDNA2[n]s  spectra were measured for dsDNA2[+ 1], dsDNA2[+ 5], and dsDNA2[+ 10] as compared with a standard dsDSA2[+ 1] without the BP photosensitizer. The result again ensured the harmlessness of BP incorporation toward the strand structure of poly(dA):poly(dT) as shown in Fig. We carried out the photooxidation of dsDNAs (2 μM) by shining LED light at 365 nm. Salt concentration (100 mM NaCl), pH (7.2 by 10 mM sodium phosphate) and temperature (25 °C) were kept constant during the reaction. The photooxidation products were digested to the mononucleosides with nucleases and they were quantified by HPLC (see Supplementary for details).OG) was mainly produced (39%) in the first 10 min, while 64% of G was consumed, and the degradation of OG followed after 10 min probably because of overoxidation (see Supplementary for details).As shown in the time course of the photooxidation of dsDNA2[+ 10] Fig. a, 8-oxod1O2 oxidation and nuclease degradation of DNA, OG has been mainly produced and otherwise only 2,2-diamino-4-[(2-deoxy-β-D-ribofuranosyl)amino]-5-(2H)-oxazolone (dOz) and N-(2-deoxy-β-D-ribofuranosyl)spiroiminodihydantoin (dSp) were obtained as the overoxidation products of OG15. Although there might be up to 25% of byproducts at 10 min in our study, our assay system tracking absorption at 260 or 300 nm was incapable of detecting these products. Nevertheless, we were able to estimate the relative 1O2 concentration near G in dsDNAs by tracing G consumption as demonstrated below.In the previous studies on 1O2, [1O2], at the oxidation site is almost constant during the reaction:v is the rate of G consumption, krG is the pseudo-first-order rate constant, and krOG is the second-order rate constant. We can estimate v at t = 0 s from the concentration decrement of G at 10 min (600 s), Δ[G]600 = [G]600 – [G]0:0 is the initial concentration of G with a constant value of 2 μM throughout these experiments. When the concentrations of 1O2 near G1 and G2 are denoted as [1O2]1 and [1O2]2, respectively, the concentration ratio of 1O2 can be deduced as follows from the equation ii:Since the initial consumption curve of G was linear as shown in Fig. 1O2 near G of interest by quantifying the G consumption within 10-min photoirradiation.The equation iii means that we can estimate the relative concentration of 15-FAM-5’ (ON4’’[+ 5]), we were able to demonstrate that the photooxidation of dsDNA4[+ 5] was oxidized only at the target G sites (lane 4), whereas a large amount of non-cleaved ON4’[+ 5] was left intact. This intactness might be due to the low photooxidation reactivity of dsDNA4[+ 5] and also the inertness of some oxidation products toward hot piperidine treatment as reported in some studies43. It should be also noted that small amount of cleaved product was obtained without a hot piperidine treatment (lane 3). This might be due to the overoxidation products, which were prone to hydrolyze at N-ribofuranoside bonds leading to β-elimination of the phosphate groups without hot piperidine treatment.We next checked the site selectivity of the photooxidation without cleaving non-oxidized sites by treating the photooxidation (1-h irradiation at 365 nm) products of dsDNA4[+ 5] with hot piperidine (1 M at 90 °C for 40 min) to cleave only the oxidized sites and analyzing the resultant products by gel electrophoresis  of the G consumption profile, almost no reactions were observed despite the close proximities of G and BP, which was also evident from no  to + 5 o51. The absence of overlaps between the fluorescence emission of BP (λmax = 551 nm) and absorption bands of G (λmax = 254 nm) excludes the possibility of a Förster-type quenching by energy transfer. However, the other two possible inactivation mechanisms described above cannot be excluded at this point. The issue of inactivation mechanism is addressed later. The base intervals at the tallest peaks (n = − 9 and + 8-to- + 10) of G-consumption profile afforded the best yields of OG (30 ~ 50%).In the medium distance range (n = − 5 to − 9 and + 6 to + 8), the G consumption rate was drastically increased with increasing base intervals, probably because the inactivation described above is limited for the short range up to n =  ± 5. This drastic disappearance of inactivation effect as the function of distance is ascribable to a quenching by Dexter-type electron transfer from BP to G1O2 concentration near G of interest as expressed by equation iii. As such, the gradual decreases in the G consumption rate with increasing G-BP separation should reflect the distance-dependent inactivation or dilution of 1O2. If the reaction retardation is related to an inactivation of 1O2, it should be due to quenching by solvent water, in which the half-lifetime of 1O2 is 3.5 μs25. We thus carried out the photooxidation of dsDNA1[n] in D2O, in which the half-lifetime of 1O2 (68 μs) is longer than that in H2O. As a result, the G-consumption rates for the photooxidation of dsDNA2(+ 10), dsDNA2(+ 15), and dsDNA3(+ 23) significantly decreased in D2O as shown in Fig. 1O2. The retardation of the photooxidation by D2O will be more deeply discussed later.Since the relatively far away regions (n = − 9 to − 17 and + 10 to + 19) are free from the inactivation effect, the extent of G consumption therein should solely depend on the 52). This biased dislocation of BP might be reflected in the G consumption profile, in which the dislocated BP position (red point 2) is closer to the hot spots than the BP-appended base position (grey point 1) as indicated by broken lines , a 1O2-trapping agent54, which is 50-times larger in concentration than dsDNA. The remained FA was analyzed by HPLC with absorbance at 216 nm (see Supplementary for details).Nonetheless, it still is intriguing that the intermolecular photooxidation is slightly more efficient than the intramolecular ones for the dsDNAs with n = − 1 to + 4. This exceptional nonreactivity at the short G-BP distances is ascribable to the quenching of BP by G through a Dexter-type electron transfer as described above, but we cannot completely abandon the possibilities of accelerated 1O2 can be explained by its 20-times higher rate constant (krOF = 1 × 108 M− 1 s− 1)54 over that for total quenching rate of 1O2 by G (ktOG = 5 × 106 M− 1 s− 1)55. The significantly large krOF/ktOG value (20-fold) does not match a hypothesis that almost all the 1O2 molecules produced from the short interval dsDNA (n =  + 3) were quenched by G and thus could not react with FA. BP's steric hindrance against 1O2-G collision, if any, would give an inversed FA residue profile, because 1O2 would be most abundant at n =  + 3 owing to no consumption by G. It is thus more adequate to explain the non-reactivity at n =  + 3 by direct collisional quenching of BP. At n =  + 3, the distance between G and BP-appended T is about 1.15 nm, which is very close to the length (1.19 nm) between the end of propyl linker and the carbon atom next to the nitro group in BP  for a BP derivative37. The type-II exclusiveness is suitable for a selective photooxidation of ONs, since type I oxidation would be accompanied by remote G oxidation as described above.In order to investigate a possibility that type I mechanism might partially contribute to the photooxidation of G by BP, the photooxidation of dsDNA2[n] was conducted in the presence of either a type I inhibitor, mannitol, or a type II inhibitor, sodium azide  of 1O2 with water is 2.4–3.2 × 105 (s-1)59 and the second-order total quenching rate constant (ktOG) of 1O2 with G is 5 × 106 (M-1 s-1)55. Considering the initial concentration of G ([G]0 = 2 × 10− 6 M) used in this study, the apparent first-order decay constant (kqG) for the quenching of 1O2 by G is kqG = ktOG[G] ≤ 10 (s-1), which is overwhelmingly smaller than kqW (kqG/kqW < 3.6 × 10− 5). Furthermore, in a study with a G derivative, the total 1O2 quenching rate (ktOG) by G was classified into those by physical collision (kqOG) and chemical reaction (krOG), the quenching rate of the former being about 45 times that of the latter (kqOG/krOG ≈ 45)46. This means that the probability of the reaction of 1O2 with G occurring is 0.85 ppm compared to the quenching by H2O. Even with such a low probability, we were able to observe the progress of G photooxidation thanks to the relatively long reaction period of 10 min.First of all, the reaction rate of 2O, the average travelling length of 1O2 in H2O within its half-lifetime (3.5 μs)24 is calculated as 205 nm from Einstein’s diffusion theory61, which is much larger than 7 nm, the furthest BP-G length for a significant photooxidation occurrence  away from the generation point is always proportional to 1/r71. Unlike such an ideal space, this study deals with a 1O2 solute whose generating point, BP, is attached on the side of a cylindrical matter, dsDNA. Therefore, G located on the back side of the cylinder across from BP is most likely accessible only by going around the cylinder despite the shorter direct distance in the spherical coordinates. This wrapping diffusion of 1O2 around a cylindrical DNA surface seems to be realized in the fluctuation cycle of G consumption profile that coincides with the pitch of 10.5 base pairs per turn in B-DNA . One possible explanation for this anomality if we assume the B'-conformation is that the TA base pairs at the both ends might be flaying, thereby the Gs near the ends shifting the locations from the canonical conformation.It should be noted here that poly(dA):poly(dT) double strands with typical CD spectra shown in Fig. 1O2. The major groove water has been reported to have about twice smaller diffusion coefficient than that of the bulk water75, probably owing to its constrained environment. Therefore, a retarded diffusion and accelerated quenching owing to a constrained H2O in the major groove might have worked against 1O2 taking this path as the main diffusion route.The fluctuated G consumption profile also suggests that penetration through the major groove is not at least the main travelling route of 1O2 along a DNA duplex can be generalized as the diffusion of particles on the surface of a cylinder. Diffusion of particles on a cylindrical surface has been described to go through the combination of adsorption, crawling, desorption, bulk diffusion, and rebinding38. The desorbed particles have to travel a much longer distance before rebinding than that can be reached by the crawling particles in the same timescale. If we assume 3.5 μs for an average travelling time (205 nm in length) of the desorbed 1O2 molecules in the bulk water, half of them would be inactivated into 3O2 when rebound to the DNA surface. In this study, we demonstrated that quenching of 1O2 by H2O was negligible in the G consumption profile, which suggests that the desorbed 1O2 molecules had little effect on the 1O2 concentration mapping along DNA. The characteristic BP-G length dependence of G photooxidation in Fig. 1O2 diffusion paths mainly via surface crawling and/or flying just above the surface by taking as short a distance as possible before inactivation into 3O2. However, care must be taken for the diffusion model because DNA structure is constantly fluctuating and thus may not be an ideal cylinder model. Since we have not directly observed 1O2 for surface diffusion, we must examine the diffusion mechanism more deeply, for example, by studying the effects of salt and temperature.Diffusion of 1O2 concentration along DNA due to diffusion from continuous sources of 1O2. This information can be valuable data that traces how molecules emanating from the surface of a nano-size cylinder diffuse to its back side.In conclusion, it was found that the optimal attaching sites of the BP photosensitizer in an oligonucleotide (ON) to photooxidize G in the complementary strand was a position separated from G by 8–10 bases. This information will be very important in the development of nucleic acid-targeting PDT. For application, the BP-appended ONs should contain inosine instead of G to avoid self-photooxidation. Also, nuclease-resistant ON analogues with bioisostere linkages such as peptide nucleic acid (PNA) should be employed. PNA could be used to target dsDNA. dsDNA could also be targeted by binding BP to a triplex-forming oligonucleotide that fits in the major groove of dsDNA. Apart from application, this study evaluated the distribution of Supplementary Information.


Accordingly, it was used to generate the SeF5− and TeF5− anions from the elemental chalcogens and to prepare the unknown tetrafluoro(phenyl)‐λ5‐selenate PhSeF4− and ‐tellurate PhTeF4− from the corresponding diphenyl dichalcogenides. In addition, we show that further derivatization of [PhTeF4]− by oxidation to trans‐PhTeF4O− and subsequent alkylation gives access to a new class of trans‐(phenyl)tetrafluoro‐λ6‐tellanes (trans‐PhTeF4OR), thus providing an approach to introduce the functional group into organic molecules.Fluorinated group 16 moieties are attractive building blocks in synthetic chemistry but only few synthetic methods are available to prepare them. Herein, we report a new oxidative fluorination reagent capable of stabilizing reactive fluorinated anions. It consists of an SF 5− salt containing a chemically inert phosphonium ion proved to be a powerful oxidative fluorination reagent for the generation of fluorinated selenium and tellurium anions, derived from the elements or the diphenyl dichalcogenides. The new anions PhSeF4−, PhTeF4− and PhTeF4O− were synthesized and characterized. Alkylation of the latter provides access to trans‐PhTeF4OR, a new class of fluorinated building blocks.An SF However, initial studies on the reaction with electrophiles showed that the phosphonium cation is fluorinated to the PF6− anion by SF4, which is formed upon fluoride abstraction from the SF5− anion. We herein show that by further increasing the chemical inertness of the phosphonium cation, the corresponding SF5− salt can be used for the generation of reactive fluorinated selenium(IV) and tellurium(IV) anions and for the synthesis of novel fluorinated functional groups.Sulfur hexafluoride is a chemically inert, nontoxic gas with large‐scale technical applications.10, 114, we decided to use bulky tert‐butyl substituents at the imidazole nitrogen atoms, which should hamper coordination of the exocyclic nitrogen atoms to electrophiles. We recently showed that the sterically encumbered phosphine P(NsItBu)3 (1)  forms inert phosphonium cations after uptake of a chloronium ion and was therefore selected for the present study.1 under an atmosphere of SF6 to 70 °C for 12 hours led to the quantitative conversion to the salt [FP(NsItBu)3]+[SF5]− (2) 3, which immediately forms the corresponding SF5− salt at −78 °C.1 and SF6 takes place at room temperature when the mixture is exposed to UV light (λ =365 nm). This accelerating effect has already been observed for the SF6 activation with other reducing agents.+ in a 1 : 1 ratio . After separation of sulfur, the salts 3 and 4 were isolated as white crystalline solids in 67 % and 60 % yield, respectively. The 19F NMR resonances of the isolated salt 4 are significantly broadened compared to those of the reaction mixture . The same effect was observed for the SF5− salt 2  as well as other SeF5− containing salts.iPr)3]+[SF5]−,5− and TeF5− anions in addition to significant amounts of PF6− anions as a result of the partial degradation of the fluorophosphonium cation . As disclosed by these experiments, the SF5− salt 2 combines two important properties: it can act as oxidative fluorinating reagent and can effectively stabilize fluorinated anions owing to the weakly coordinating nature of the chemically inert phosphonium ion.The 2 for the oxidative fluorination of organoselenium and organotellurium compounds. Common fluorination reagents such as XeF2,+[PhTeF4]− (5), which contains a novel tetrafluoro(phenyl)‐λ5‐tellurate anion, in addition to stochiometric amounts of thiothionyl fluoride . Further indication for the formation of SSF2 was obtained by the addition of Ph3P to the product mixture, which gave SPPh3 and Ph3PF2 next to [FP(NsItBu)3]+ in a 2 : 1 : 2 ratio as determined by 31P NMR spectroscopy. The [PhTeF4]− salt 5 was isolated as a white crystalline solid in excellent yield. It shows good solubility in polar solvents such as MeCN and CH2Cl2 and moderate solubility in THF.To further explore this potential, we considered using  as XeF2,3a, 3g4]− anion completes the series of tetrahalo(phenyl)‐λ5‐tellurate anions [PhTeX4]− .19F NMR spectrum and a pentet at 1349.3 ppm (1JTeF=472 Hz) in the 125Te NMR spectrum  are slightly elongated compared to those of [TeF5]− (1.923–1.973 Å).4]−  salts, the structure of 5 is built up of isolated anions [PhTeF4]− and cations [FP(NsItBu)3]+.The [PhTeF2 with diphenyl diselenide required more drastic conditions and could not be performed in standard borosilicate vessels. Heating a THF solution of 2 and diphenyl diselenide for 48 hours at 90 °C in a sealed PTFE vessel afforded [FP(NsItBu)3]+[PhSeF4]− (6) after workup in 60 % yield. Crystals of 6, suitable for an XRD analysis, were obtained by carefully layering a THF solution with diethyl ether. The selenium(IV) anion of 6 is isostructural to the tellurium congener in 5 .6 represents the first aryl tetrahalo‐λ5‐selenate anion of type [RSeX4]−. Similar square planar coordination of aryl selenium units can be found in the dimers of the neutral compounds RSeX3 , which exhibit intermolecular Se⋅⋅⋅X interactions in the solid state.− salt shows a broad signal at −25.0 ppm in the 19F NMR spectrum and a singlet at 1022.7 ppm in the 77Se NMR spectrum suggesting a dynamic process. However, a variable temperature NMR experiment revealed only a broadening of the 77Se resonance at low temperature. To investigate the origin of this dynamic process, a second conformer with a fluoride at the apex of the square‐pyramidal structure was considered. However, its Gibbs free energy is 70 kJ mol−1 higher than that of the experimentally observed structure. The “concerted” isomerization has an energy barrier of ΔG≠298=120 kJ mol−1 and proceeds via migration of a fluorine atom to the trans position of the phenyl group, leading to a significant elongation of the corresponding Se−F bond to 2.679 Å in the transition state structure . Fluoride dissociation, in the presence of an acceptor, and subsequent reassociation represent an alternative mechanism. Computational studies of the  dissociation of F− from PhSeF4− in the presence of HF to form PhSeF3 and FHF− was found to be monotonously uphill in enthalpy. However, a low‐lying intermediate solely stabilized by entropic contributions was detected (ΔG298=−7 kJ mol−1). Calculations suggest that in this species F− is dissociated from PhSeF4− but due to the acceptor kept in close vicinity. Given the low energy differences, fast interconversion between the two complexes is possible . Thus, fluoride dissociation/association mediated by an acceptor is the likely explanation for the observed dynamics in the NMR spectra of 6.The reaction of id state.5a, 244 and PhEF3 using the method reported by Christe and co‐workers  or of tellurium with selenium (SeF4) both decreases the FIA by about 50 kJ mol−1. In line with this trend, PhSeF3 displays the lowest electrophilicity in this series, which is consistent with the experimental observation that 6 reacts readily with the glass surface of the reaction vessel and decomposes quickly in the presence of moisture, whereas 5 does not react with the glass surface and decomposes slowly in the presence of water within several weeks .To rank the stability of the obtained anions with respect to fluoride abstraction,rs Table .[25] T5 is easy to isolate and rather stable in air, it appeared to be an interesting platform for further derivatizations of the new [PhTeF4]− anion. We first attempted alkylation to access mixed aryl/alkyl tetrafluoro‐λ6‐organotellurium compounds. These species are poorly studied and have been prepared by fluorination of organotellanes R2Te.[4]− anion turned out to be a very sluggish nucleophile, which did not react with allyl iodide at temperatures up to 100 °C. Using methyl triflate or (Et3O)BF4, slow decomposition of 5 was observed at room temperature under formation of PF6− and alkyl fluorides . An XRD study of a crystal grown from the reaction mixture revealed a dicationic TeIV compound 11 generated by partial degradation of the phosphonium ion . We proceeded in our efforts in further derivatization by reducing the fluoride donor ability of the [PhTeF4]− anion via oxidation with 3‐chloroperbenzoic acid (m‐CPBA). The [PhTeF4]− salt 5 was cleanly oxidized to the [PhTeF4O]− salt 7 using m‐CPBA  and longer Te−F bonds (1.894–1.919 Å) than those of the “teflate” anion [TeF5O]− .4]− anion with m‐CPBA was unselective presumably due to the deoxyfluorination of 3‐chlorobenzoic acid by 6 .The y Figure . The [Ph4O]− anion can be alkylated by common reagents such as methyl iodide, allyl iodide and benzyl bromide to afford trans‐alkoxytetrafluoro(phenyl)‐λ6‐telluranes 8–10 in good yield  species increase in the order [trans‐PhTeF4O]− (7: 3231 Hz), trans‐PhTeF4OR (8–10: 3526–3548 Hz), [TeF5O]− (3643 Hz),trans‐(MeO)2TeF4 (3672 Hz),trans‐(MeO)2TeF5]−.4(OR) group on arenes and the trans isomers are unknown. This is likely due to the fact that the reaction of PhTeF5 with an excess of methanol or water selectively produces cis‐PhTeF4(OR) .[cis and the trans isomer of PhTeF4(OMe) are very similar in energy, with DLPNO‐CCSD(T)/def2‐TZVP calculations in THF slightly favoring the cis isomer by −0.8 kJ mol−1 in free energy. This difference might very well be within the error margin of the calculations, in particular since the relativistic effects of the tellurium atom are only considered via effective core potentials and not explicitly included in the calculations. Further exchange of fluorine atoms with OH groups in cis‐PhTeF4(OH) was shown to happen much slower.8–10 can be handled in air with no observable degradation. A hydrolysis experiment showed that 10 undergoes very slow exchange of fluorine atoms for OH groups (less than 1 % after 3 hours) when dissolved in a 10 : 1 mixture of acetonitrile and water, forming the putative hydrolysis product PhTeF3(OH)(OCH2Ph).Gratifyingly, the new [PhTeFd Scheme . The phe2) consisting of an SF5− anion and an inert phosphonium cation is reported. Compared to other SF5− salts, 2 exhibits exceptional thermal stability, making it a powerful reagent for the generation and stabilization of reactive fluorinated anions. For example, 2 was used for the fluorination of elemental selenium and tellurium to the corresponding SeF5− and TeF5− salts. We also synthesized and characterized the new anions PhSeF4−, PhTeF4−, and trans‐PhTeF4O− from the corresponding diphenyl dichalcogenides. Alkylation of trans‐PhTeF4O− leads to the first trans‐(phenyl)tetrafluoro‐λ6‐tellanes (trans‐PhTeF4OR), demonstrating a way to introduce the functional group into organic molecules. Given the stability of the trans‐PhTeF4OR motif, it could become an alternative candidate for the arsenal of lipophilic electron‐withdrawing groups5 group,[In conclusion, a new oxidative fluorination reagent  should be addressed to the authors.Supporting InformationClick here for additional data file.Supporting InformationClick here for additional data file.Supporting InformationClick here for additional data file.Supporting InformationClick here for additional data file.Supporting InformationClick here for additional data file.Supporting InformationClick here for additional data file.


In the current work, the H‐T phase diagram for current I//[100] and I//[110] shows a large difference with H normal to the film plane, which is ascribed to the response of a variable range of hopping process to H with the in‐plane anisotropic hopping probability of charge carrier. With H rotating from the out‐of‐plane to the in‐plane direction, the preferred occupancy of the 3dz2−r2 orbital causes a decrease of spin‐orbital coupling and lowers the activation energy, inducing a gentler melting process of a charge‐ordering insulator. This work shows that the melting path of a charge‐ordering insulator phase can be largely modulated in manganite with anisotropy.Multiple phases coexist in manganite with simultaneously active couplings, and the transition among them depends on the relative intensities of different interactions. However, the melting path with variable intensities is unclear. The concentration and the ordering of oxygen vacancy in previous work are found to induce ferromagnetic charge‐ordering insulator phase in [(La H‐T phase diagram of charge‐ordering phase in [(La0.7Sr0.3MnO3)10/(SrTiO3)5]n superlattice shows large in‐plane anisotropy with H normal to film plane, and with H rotating from out‐of‐plane to in‐plane direction, the melting of this phase becomes gentler, which are due to the response of a variable range of hopping process to H with the in‐plane anisotropic hopping probability of charge carrier. In manganite, multiple couplings, such as double‐exchange, super‐exchange, and electron‐phonon coupling, have been proposed to describe the appearance of ferromagnetic‐metallic (FM‐M), ferromagnetic‐insulator (FM‐I) antiferromagnetic insulating (AFM‐I) and charge‐ordering insulating (COI) phases. Specially, the ferromagnetic charge‐ordering insulator (FM‐COI), could coexist with other phases in the frame of double‐exchange with impurity randomness in doped manganite, which is sensitive to magnetic field H and temperature T. With the kinetic energy of the charge carriers dominates over the COI instability, the COI was proposed to melt and become a FM‐M or paramagnetic insulator (PM‐I), and the anisotropic spin‐orbital coupling (SOC) and orbital occupancy could play an important role in this process. To date, the melting process of COI phase under external stimulus remains unclear and warrants further study.Transition metal oxides1 poss was presented to induce the FM‐COI phase in wideband manganite La0.7Sr0.3MnO3, which was susceptible to H and T. The Mott's variable‐range hopping (VRH) model was proposed to explain the transport properties in the COI phase. At low H, the resistivity decreases due to the quantum interference between paths connecting impurity sites during the hopping process; with further increasing H, the field‐induced spatial shrinkage of electronic orbital would increase the resistivity. At the same time, strong H tends to enhance the hopping probability of the charge carrier along the direction of H, which depends on the electronic orbital distribution and SOC intensity, and even could induce the collapse of the high resistivity COI phase. For an epitaxial film with anisotropy of crystal structure, the intensities of different couplings might vary with the spatial direction and then affect the transition process of COI phase under the external stimulus.The ordering of oxygen vacancy characterized by combined techniques,11 was0.7Sr0.3MnO3/SrTiO3 (LSMO/STO) superlattice are fabricated with [LSMO10/STO5]n configuration (SLn) on (001) LaAlO3 (LAO) substrate, 10‐unit cell (UC) LSMO and 5 UC STO in each period, and n is the number of periods. For both SL2 and SL5, the H‐T phase diagram shows large anisotropy for current with H normal to the film plane, I//[100] and I//[110]. The high resistivity the COI phase, which is sensitive to the strain status of the superlattice, was melted into a low resistivity phase with multiple steps (sharp change of resistivity). There is one more step for I//[110] compared to that for I//[100], which is ascribed to the response of VRH process to high H with in‐plane anisotropic hopping probability of charge carrier. In addition, H could lower the activation energy and increase the hopping distance, which makes the melting process gentler. With H rotating from the out‐of‐plane to the in‐plane direction, the preferred occupancy of 3dz2−r2 causes a decrease of SOC and lowers the activation energy, thus inducing a gentler melting process as observed in the magnetoresistance measurement. This work indicates that the melting path of COI phase could be largely modulated by changing the strength of different couplings.In this work, the La210/STO5]n superlattices (SL) were grown on (001) LAO substrate at 940 °C by pulsed laser deposition, the oxygen pressure was 1 mTorr for STO growth and 100 mTorr for LSMO growth. After deposition, the sample was cooled down at 15 °C /min in a 100 mTorr oxygen atmosphere. The appropriate oxygen pressure during STO growth and the existence of STO with larger out‐of‐plane lattice constant was proposed to promote the preferred location of oxygen vacancy on the (001) La/SrO plane in LSMO layer, which was crucial for the formation of the FM‐COI phase. For comparison, 50 UC and 20 UC LSMO single layers were also deposited on LAO substrate. There was no sign of the FM‐COI phase in Figure αK1 radiation. The magnetic properties were measured by a superconducting quantum interference device, and the transport properties were measured by the Physical Property Measurement System (PPMS) using linear four‐point probe. and [110] direction, respectively, and the H was along the out‐of‐plane [001] direction. The ρ‐T curves were measured during the warming process with different H after zero‐field cooling from 300 to 10 K. The thermomagnetic measurement and magnetic hysteresis loop at low temperature in Figure TC. With increasing T, there is two sharp down‐turn of resistivity (T1 and T2) with I//[100], indicating the melting of COI phase in LSMO layer into metallic phase; with H up to 9 T, the melting of COI phase was boosted with decreasing melting temperature. Similar behavior is observed for ρ‐T curves with I//[110] in Figure T*) with H = 9 T. In order to get more information about these multiple jumps in resistivity, MR curves at different T were measured with H along out‐of‐plane direction after zero‐field cooling from room temperature to 10 K and then back to targeted T. Figure H‐T phase diagram is shown in Figure H, one additional phase transition (T*) was induced with I//[110], the origin of which would be the focus of the following study.ρ=ρ0exp(T0T)1/4, and the activation energy EA required to induce the hopping could be obtained by EA=−KBT2ρ(dρdT), BK is the Boltzmann constant. Other model about the transport process are discussed in Figure EA (red curve) shows obvious temperature dependence in Figure T . The nonzero slopes of EA‐T curve were the signature of variable range hopping, and the anomaly corresponds to the charge‐ordering transition. The constant EA above Tp indicates that transport is dominated by the nearest neighboring hopping process at high T, of which the activation energy does not present temperature dependence. From the A‐TE curve for H = 0 with I//[100], there are two close anomalies (sharp jump out of the range of figure), corresponding to two sharp down‐turns in ρ‐T curve, and the AE value around these two anomalies are also close, indicating that the transport process should be similar. In addition, the magnetic measurement does not show any features around T1 and T2. Based on these experimental results, the T1 and T2 should be due to the spatial inhomogeneity in the film: the creation of percolative paths  at different places requires different temperatures and thus induce multiple jumps in the ρ‐T curve. For I//[110], the shape of A‐TE curve with 9 T field changes largely compared to that without H, showing three anomalies , which indicates that the magnetic field affects the transport process/mechanism. Considering the same direction of H, the difference in transport behavior between I//[110] and I//[100], should come from the anisotropic‐conducting environment in the film plane, rather than additional phase transition, which would be discussed below.In the manganite COI phase, the Mott's VRH model was proposed to describe the transport properties in low temperature,12ρ=ρ the crystal structure of SLs was analyzed in Figure L scan shows the (002) main peak and satellite peaks, labeled as arrow and diamond, respectively, indicating the formation of superlattice structure. The SL2 was fully strained by the (001) LAO substrate according to the (002) and (−103) RSM, and the out‐of‐plane lattice (c = 4.029 Å) was elongated with compressed in‐plane lattice constant (a = 3.790 Å) compared to that of bulk LSMO (3.880 Å); In addition, the oxygen octahedral rotation shows a0a0c− pattern according to the half‐inter diffraction in Figure ρ‐T curves origins from the non‐uniformity. In order to get more correlation between the crystal structure and the hierarchy in H‐T phase diagram, the strain conditions of superlattice SL5 with n = 5 were also shown in Figure a0a0c− octahedral rotation pattern, but the SL5 shows less tensile strain (c = 4.013 Å) compared to SL2. The change of out‐of‐plane lattice constant suggest the occurrence of the strain relaxation, and the strain status of superlattice with different periods has been discussed in Figure 2 and SL5, has an obvious effect on the materials properties.With a strong correlation between materials properties and crystal structure,24 theT1) in RT curve with I//[100] for SL5 in Figure 2; with H the melting of COI phase was boosted with decreasing T1, which has similar trend as that of SL2. The MR curve was measured at different temperatures: At 115 K close to T1, the H could melt the CO phase at HM1 ≈1.6 T, and with increasing H it could back into high resistivity phase at HR′ ≈6.1 T, which was ascribed to the combing effect of variable range hopping (VRH) and the thermal fluctuation around the phase transition point. Then, with decreasing H, the high resistivity state could be melted to low resistivity state at HM′ ≈5.1 T, however, it cannot return back to its initial high‐resistivity state with further decreasing H, which suggests the coexistence of multiple phases. At 130 K above T1, the film is at ferromagnetic metallic phase, and the resistivity gradually increase at high H  due to the shrinkage of electronic orbital. One other factor inducing increasing resistivity with magnetic field is the Lorentz effect. In LSMO manganite, the estimated mean free path l ≈ 2 nm and the cyclotron orbit cr ≥ 6.8 µm, suggesting that the influence of the Lorentz effect in our case is negligible. Figure H‐T phase diagram: The dashed line is obtained from the MR curves, which reveals the coexistence of the FM‐M phase and FM‐COI phase. Above T1, there is a tiny area (gradient pink color) between HR′ and HM′, which has different properties from FM‐M as discussed below.With increasing temperature, there is one sharp down‐turn of resistivity T1 in RI//[110] direction, the zero‐field ρ‐T curve of SL5 shows one down‐turn, and the magnetic field (H > 0) could induce one additional down‐turn (T*) compared to that with I//[100], which is similar to that in SL2 but with one fewer down‐turn. The change from SL5 to SL2 is studied by fabricating superlattice with three periods (SL3) on LAO substrate. The ρ‐T curves with I//[110] of SL3  and T*, which seems counterintuitive in manganite. The multiple melting of COI with different physical origins has been observed in other manganite work, and the anisotropic SOC is proposed to explain the anisotropic melting of COI phase. The metallic cluster in manganite tends to grow along the magnetic easy axis, and the anisotropic in‐plane strain could induce anisotropic transport properties via different percolation path. In current superlattices, the preferred occupancy of eg orbital 3dr2‐z2 has the main contribution to the conductivity. The ρ‐T curve indicates that the COI phase is easier (lower T1) to melt into FM‐M phase along [110] direction without H, suggesting that the SOC is stronger with enhanced coupling between neighboring Mn sites along this direction, although the lobes of the eg orbital (3dr2‐z2) are not directing at [110] direction. Such phenomenon has been reported in previous work. In the VRH process, the charge carrier transport is mediated by the spatial extension of the electronic orbitals, and orbital shrinkage would hinder the probability of charge hopping among different sites. The spatial extension of orbital is subject to magnetic field, which could cause the shrinkage of spatial distribution in the film plane for both 3dr2‐z2 and 3dx2‐y2 orbitals. Considering the relative higher occupancy of 3dr2‐z2 orbital and higher possibility of charge hopping along [110] direction, the orbital shrinkage induced by magnetic field would affect the charge hopping process along [110] direction obviously, which induces the widen temperature range of COI phase along [110] direction. The appearance of sharp down‐turn of resistivity is an overall effect of all conductive paths and a statistical outcome according to the percolation theory, with good stability as shown in Figure ρ‐T curve at each sharp down‐turn decreases compared to that without H. Comparing the value of AE, H could lower the activation energy, 113 meV at 0 T and 82 meV at 4 T. According to VRH model, the activation energy is described as EA=34πd3N(EF), d is the distance between hopping sites, and N(EF) is the density of states at Fermi level (constant in Mott VRH). The decrease of activation energy under H suggests the increase of hopping distance, which may attenuate the effect of appearance of conducting bridge (appearance of down‐turn in resistivity) among clusters, and decrease the relative change of resistivity.With T1 for I//[100] has the same trend as T1 for I//[110] with close value in SL5; What is interesting is that the HR′ curve in Figure Tp from ρ‐T curves in Figure Tp with H for I//[110] is related to the H‐dependent VRH process. The EA‐T curve under high H also shows temperature‐dependent above Tp, which could support the above argument that the transport mechanism above Tp has more contributions, besides the nearest neighboring hopping. In Figure T* exists with medium H, either too high, and too low H cannot induce the appearance of T*. The HM2 curve, which overlaps with T* partially, merges into T1 curve with increasing H, suggesting that H has a significant effect on the appearance of T*. Between HM1 and HM2 in MR curve, the resistivity decreases linearly with magnetic field, signaling the quantum interference (QI) effect during VRH process in already‐formed COI phase. According to the above discussion, in the area enclosed by T1 (or HM1), T* and HM2 curves of Figure H‐induced orbital shrinkage would hinder the probability of charge hopping among different sites and increase the resistivity. For I//[110] with stronger SOC, the probability of charge hopping is sensitive to the magnetic field‐induce orbital shrinkage, resulting in widen temperature range of COI phase , around which the effect of thermal fluctuation would be important and might induce the recovery of high resistivity phase from low resistivity phase in the VRH process. With I//[110] strong H could widen the temperature range of high resistivity area . The anisotropic behavior should come from the sensitivity of charge hopping to thermal fluctuation, and the orbital spatial distribution along different directions.To sum up, the condition of 2, T1 and T2 for I//[100] also has the same trend as T1 and T2 for I//[110] in Figure 2 and SL5, the same mechanism has been proposed for T* in SL2. The persistent transition T1 and T2 exist along both in‐plane [100] and [110] directions, and the field‐induced emergent transition T* only appears along [110]. The sharp down‐turn at T1 and T2 comes from the collapse of the COI phase when the kinetic energy of the charge carriers through double exchange interaction dominates over the COI stability, and the emergent conducting path forms along [110] direction, which could be induced by magnetic and then T* appears. Considering that the activation energy AE of T1, T2, and T* are similar and T* only appears for I//[110], the appearance of T1 and T2 without magnetic field is due to the spatial inhomogeneity in as‐grown film, and appearance of additional T* with the magnetic field is ascribed to the additional spatial inhomogeneity induced by application of strong magnetic field, arising from the competing between charge hopping in double‐exchange process and the variable‐range hopping. With larger tensile strain along the out‐of‐plane direction for SL2 (c = 4.036 Å) compared to SL5 (c = 4.013 Å), the COI phase exists in a wider temperature range in SL2, suggesting that the out‐of‐plane tensile strain could stabilize the COI phase. In order to verify the strain effect on the COI phase, superlattice with 10 periods (SL10) on LAO substrate was fabricated, and strain relaxation is observed. The ρ‐T curve also shows insulator behavior at low temperatures, but no abrupt jump occurs with relatively low resistivity compared to that of SL2 and SL5. The measured resistivity is the averaged results of the whole superlattice, and the gradual increase of resistivity with decreasing temperature  is the same for H along different directions, but the process is quite different. For H close to [001] direction (θ = 5˚), there are several jumps with increasing H, and the resistivity cannot back to its initial value with decreasing H, while there is no jumps for H//[010] (θ = 90˚) and the resistivity could back to its initial value. The continuous change of resistivity without sharp jumps means a small relative change of resistivity with each step length of magnetic field. The measurements of crystal structure indicates a larger out‐of‐plane lattice constant c than in‐plane a, and the electrons tend to occupy 3dz2−r2 orbital. The anisotropic orbital ordering might cause anisotropic melting of the insulator phase due to the intimate coupling between spin and orbital degree of freedom. In the current work, the orbital ordering would induce anisotropic response of the SOC and double‐exchange interaction to the magnetic field. Along the direction with a high Mn‐O orbital integral, the magnetic field would increase the hopping probability of electron largely that could enhance the SOC and double‐exchange interaction along out‐of‐plane directions. Along other directions, the effect of magnetic field on hopping probability of electron would be weakened by a limited orbital integral. With H rotating from the [001] to [010] direction, the effect of H on enhancing magnetic interactions decrease, which would weaken the tendency of sharp melting of COI phase. The melting of CO phase would therefore take place gradually without a sharp down‐turn for H//[010] as observed. This also could explain the difference between θ = 5˚ and θ = 0˚  was also obtained with 2, the AMR shows a sharp change of resistivity with H along different directions as shown in Figure H//[001], and it experiences more than one jump for H//[010]. A strong magnetic field is required to melt the COI phase in SL2 due to its high stability, and the resistivity under H is dominated by the QI effect in the measured range of magnetic field, revealed as the linear dependence of resistivity on H and labeled as yellow dashed line in Figure  to the Mott's characteristic temperature T0, changes with direction of H. Comparing the MR at 90° and 0°, the lower slope indicates a smaller T0 and activation energyAE with H//[010]. Similar to the ρ‐T curves under high H, the decrease of EA would increase the hopping distance and attenuate the effect of appearance of conducting bridge between clusters, inducing a gentler change of resistivity at each jump as observed. However, with H 45° to the normal direction, the MR shows quite a different behavior: multiple down‐turn appears, and fluctuation between different states appears with decreasing H, which should correspond to the transition between different conditions. The AMR of both SL2 and SL5 with similar trend indicates that by changing the strength of different interactions, the melting path of COI phase could be largely modulated.For SL40.7Sr0.3MnO3/SrTiO3 superlattice with different periods were fabricated on (001) LaAlO3 (LAO) substrate, and the melting process was investigated. For both SL2 and SL5, the magnetic field‐temperature phase diagram shows anisotropy for I//[100] and I//[110] with the magnetic field normal to the film plane. The response of the VRH process to magnetic field is proposed to cause the additional step for I//[110], and the anisotropy comes from the in‐plane anisotropic hopping probability of charge carrier. With magnetic field rotating from the out‐of‐plane to the in‐plane directions, the preferred occupancy of 3dz2−r2 causes decreasing spin‐orbital coupling and weakens the tendency of the COI collapse, which causes gentler melting of the COI phase in magnetoresistance curve. This work indicates that the melting path of COI phase could be modulated by changing the strength of different couplings.The LaThe authors declare no conflict of interest.Supporting InformationClick here for additional data file.


Two analogues of the diterpene precursor geranylgeranyl diphosphate with shifted double bonds, named iso‐GGPP I and iso‐GGPP II, were enzymatically converted with twelve diterpene synthases from bacteria, fungi and protists. The changed reactivity in the substrate analogues resulted in the formation of 28 new diterpenes, many of which exhibit novel skeletons. Two analogues of geranylgeranyl diphosphate with shifted double bond were enzymatically converted with twelve diterpene synthases. The double bond shift causes a change of reactivity that results in the formation of many diterpenes with novel skeletons. A total number of 28 new diterpenes is reported and their mechanism of formation is discussed. The pyrophosphate sensor,The astonishing structural complexity observed in terpenes is generated from very few acyclic and achiral precursors. Only two CZ‐configured or hydrogenated double bonds.[Catenulispora acidiphila.Interference with terpene biosynthesis aiming at novel TS products is possible in two ways: Either the enzyme can be modified through site‐directed mutagenesis,le bonds.21 Most Streptomyces cyaneofuscatusAllokutzneria albata1) and isocembrene A  and cembrene A (4). With GGPP the BdS‐catalysed reaction to bonnadiene starts with an isomerisation to geranyllinalyl diphosphate (GLPP) and subsequent 1,14‐cyclisation to a 2Z configured macrocycle, followed by further cyclisation steps (Scheme S1). The structural modification in iso‐GGPP II, formed from iso‐FPP and IPP by GGPPS, leads to a disturbed enzyme‐substrate interaction in which the 1,14‐cyclisation is still promoted, but with retained 2E configuration in A, while the downstream steps of the cascade are interrupted and direct formation of 1 and 2 is observed.The incubation of iso‐FPPS. xinhaiensis5 was isolated . With GGPP as substrate SpS catalyses an initial 1,10‐cyclisation (Scheme S2), which is not possible with iso‐GGPP II. Remarkably, a very similar 1,18‐cyclisation to B substitutes for the natural cyclisation mode. A subsequent 1,3‐hydride shift and attack of water result in 5 C, followed by 1,3‐hydride shift and attack of water  from Saccharopolyspora spinosa7  from 7 Scheme A. The naE include the deprotonation to germacrene B (14) or quenching with water to hedycaryol 8, Table S6, Figures S37–S44). The pseudo‐C3 symmetry of the macrocycle in 8 resulted in almost identical chemical shifts for carbons in corresponding positions of the two isoprene units marked in bold. An unambiguous assignment was possible using iso‐FPP in conjunction with the five isotopomers of singly labelled (13C)IPP and product analysis through 13C NMR . With GGPP SaS shows an initial 1,14‐cyclisation (Scheme S4) that is surprisingly turned into a 1,18‐cyclisation with iso‐GGPP II, although the C14=C15 double bond remains unchanged in this substrate analogue. A possible explanation lies in the second ring closure in spiroalbatene biosynthesis that happens between C1 and C10, suggesting that the C10=C11 double bond of GGPP is also close to C1 in the active site of SaS. Therefore, only a small conformational change for iso‐GGPP II may lead to the observed altered cyclisation mode.With FPP as substrate alternative reactions from intermediate B were obtained by conversion of iso‐GGPP II with variediene synthase from Aspergillus brasiliensis  and prenylpseudogermacrene D (10) were obtained . With phomopsene synthase from Nocardiopsis rhamnosiphilia  smaller amounts of 7, 9 and 10, and the new diterpene alcohol prenylpseudohedycaryol . Notably, as observed for SoS also AbVS and NrPS change the natural initial 1,11–10,14 cyclisation with GGPP (Schemes S5 and S6) to a 1,18‐cyclisation with iso‐GGPP II. Another minor product obtained from this enzyme was characterised as pseudodollabella‐3,7,18‐triene . This compound requires a 1,2‐hydride shift to D, cyclisation and deprotonation.Further alternative deprotonation products from cation 1, 2 and 5–12 were also observed among the products obtained from iso‐GGPP II with several other bacterial DTSs. Especially the prenylpseudogermacrenes A–D (7–10) and prenylpseudohedycaryol (11) were frequently found .Different patterns of compounds 13C‐labels for a highly sensitive analysis by HSQC. For this purpose, the labelled probes (R)‐ and (S)‐IPP,E)‐ and (Z)‐IPP1 and 2 could be tentatively assigned from their optical rotations  which are of opposite sign to the reported optical rotations of (R)‐3 R)‐4 5 NOESY based assignments of diastereotopic hydrogens were possible , and isotopic labelling experiments with (E)‐ and (Z)‐IPP  pointed to the absolute configuration as shown in Scheme 11 no assignment could be made from labelling experiments, but the results showed a high enantiomeric purity of 11 obtained with HdS , but only 70 % ee for 11 obtained with NrPS . For 12 the production was too low to gain conclusive insights into its absolute configuration from labelling experiments.The absolute configurations of terpenes can be determined with stereoselectively deuterated precursors, setting additional stereogenic centers in the terpene synthase products of known configuration. The relative configuration of the naturally present stereogenic centers to the stereogenic centers at the deuterated carbons can be determined through NOESY spectroscopy and allows to conclude on the absolute configuration of the terpene. Our method makes use of additional Dyctostelium discoideum16) as main product , suggesting that 16 exists in two enantiomeric slowly interconverting conformers. With 18‐hydroxydolabella‐3,7‐diene synthase (HdS) from Chitinophaga pinensis17) as the main product (Scheme 16 and 17 a cyclisation cascade is followed similar to that for the native enzyme products (Schemes S7 and S8). For a few other DTSs an interruption of the cyclisation cascade at an early intermediate was observed, e.g. with NrPS the bicyclic compound dolabella‐3,8(17),18‐triene (18) was obtained as the main product . Compounds 17 and 18 arise through cation F, but with different configurations at C12, which reflects in both cases the stereochemistry of the natural intermediate from GGPP (Schemes S6 and S8).The conversion of iso‐GGPP I with the C6=C7 double bond of GGPP shifted to C7=C14 with several DTSs resulted in the iso‐compounds showing the corresponding double bond shift in comparison to the native products from GGPP. Specifically, β‐pinacene synthase (PcS) from the protist Colletotrichum gloeosporioides Dolasta‐1(15),8‐diene Synthase (CgDS)25) which will be explained below and several diterpene hydrocarbons ,11‐triene  and dolasta‐1(15),8‐diene (20), the natural product of CgDS from GGPP.F to G and deprotonation to 19, followed by reprotonation at the olefinic methylene carbon to induce a second ring closure to 20. Notably, the mechanism towards 20 is very similar to its formation from GGPP, only with the reprotonated double bond in the neutral intermediate being located in a different position (Scheme S9).Incubation of iso‐GGPP I with the bifunctional fungal PT‐TS enzyme 21) and B (22), besides the diterpene alcohol albataxenol (23) as the main product . Notably, the NMR spectra of 23 recorded at 293 K showed line broadening, but sharper signals could be observed at 344 K. The isothunbergenes require 1,14‐cyclisation of iso‐GGPP I and two sequential 1,2‐hydride shifts to H, in analogy to the reactions with the native substrate GGPP (Scheme S4). Subsequent deprotonation with formation of an  or ‐diene portion leads to 21 and 22 .With SaS iso‐GGPP I was converted into the hydrocarbons isothunbergene A (24) and B . Also in case of 24 the initial cyclisation steps towards K are analogous to those observed with GGPP (Scheme S5), but later the exo‐methylene C19 takes part in a 3,19‐cyclisation with attack of water, leading to new skeletons  iso‐GGPP I was converted into a complex mixture of several diterpene hydrocarbons and two alcohols Figure S147). The alcohols were isolated and structurally characterised as variexenol A , isoxeniaphyllene (27) and prenylisodauca‐3,7(14)‐diene . The name of 27 was assigned, because this compound exhibits the same skeleton as xeniaphyllenol ‐ and (S)‐‐iso‐GGPP I with CotB2 showed deprotonation from C1 with specific loss of the 1‐pro‐S and retainment of the 1‐pro‐R hydrogen . The cyclisation modes observed here for the three compounds 26–28 deviate from the natural 1,11–10,14‐cyclisation of GGPP (Scheme S10).Similar findings have been made for cyclooctat‐9‐en‐7‐ol synthase (CotB2)7 Scheme A. Compou1 Scheme B. IncubaCatenulispora acidiphila (CaCS),30) and catenulixenol . Their formation follows the natural cyclisation cascade with GGPP closely 32) and wanjuxenene . Also in this case the cyclisation cascade follows in its initial steps the reactions towards natural wanjudiene (Scheme S12), starting with an isomerisation of iso‐GGPP I to iso‐geranyllinalyl diphosphate I (iso‐GLPP I), followed by a 1,14‐cyclisation to T, 1,3‐hydride migration to U and 1,10‐cyclisation to V ‐ and (S)‐‐iso‐GGPP I and GC/MS analysis of the products, showing the cleavage of a deuterated iPr group from the S‐configured substrate . Initially, the 1,2‐hydride shift from Z to Aa was not taken into consideration, but rather a direct deprotonation of Z to 33 was assumed. However, the deuterium atoms from both substrates (R)‐ and (S)‐‐iso‐GGPP I remained in the product , with incorporation of deuterium from (R)‐‐iso‐GGPP I into a neighbouring position of C1 as indicated by a small upfield shift for the labelled carbon . Remarkably, the olefinic methylene C19 in iso‐GGPP I becomes involved in two cyclisation events towards 33.Wanjudiene synthase from V Scheme . Deproto34, Table S27, Figures S227–S234). This compound can be formed by 1,10‐cyclisation followed by deprotonation with cyclopropanation  that is a neutral intermediate towards the SpS product spata‐13,17‐diene (Scheme S2) and was first isolated from Cneorum tricoccon.34 was obtained from iso‐GGPP I with SoS ,The enzyme reaction of iso‐GGPP I with SpSn Scheme . The hydR)‐ and (S)‐‐iso‐GGPP were synthesised (Scheme S13) and their enantiomeric purity was shown to be high by Mosher ester analysis . Their conversion with HdS and HSQC analysis of the products allowed for the assignment of the absolute configuration of 17 . Analogously, the conversion with NrPS and CgDS revealed the absolute configuration of 18  and 19 . In the enzyme reactions with SaS one of the hydrogens at C1 migrates for all products so that no stereogenic anchor can be introduced to allow a secure determination of absolute configurations. However, for 20 and 21 it is the same 1‐pro‐S hydrogen as for the natural enzyme product spiroalbatene that is shifted  so that the absolute configurations should be analogous to the absolute configuration of spiroalbatene.R)‐ and (S)‐‐iso‐GGPP with AbVS established the absolute configurations of 24 and 25 , and with CotB2 the absolute configurations of 26 and 27 were shown . For the enzyme reactions with CaCS to 30 and 31 one of the C1 hydrogens is migrating , but again this is the same hydrogen that also migrates in catenul‐14‐en‐6‐ol biosynthesis (Scheme S11),pro‐S hydrogen is shifted into the iPr group in the formation of 32  and 33 , which is the same hydrogen that also migrates in wanjudiene biosynthesis (Scheme S12).34 with both enzymes SpS and SoS proceeds with loss of the 1‐pro‐S hydrogen in the cyclopropanation , which is also observed for the SpS reaction to spata‐13,17‐diene (Scheme S2).32–34 should also be analogous to their natural counterparts.The absolute configurations of the products derived from iso‐GGPP I were also determined through the enantioselective labelling strategy. For this purpose,  should be addressed to the authors.Supporting InformationClick here for additional data file.


The crystallization behavior of iPPC8 copolymers is compared with the crystallization from the melt of propene–ethylene, propene–butene, propene–pentene, and propene–hexene copolymers. The results show that the behavior of iPPC8 copolymers is completely different from those described in the literature for the other copolymers of iPP. In fact, the maximum amount of γ form achieved in samples of different copolymers of iPP generally increases with increasing comonomer content, while in iPPC8 copolymers the maximum amount of γ form decreases with increasing octene content. The different behaviors are discussed based on the inclusion of co-monomeric units in the crystals of α and γ forms of iPP or their exclusion from the crystals. In iPPC8 copolymers, octene units are excluded from the crystals giving only the interruption effect that shortens the length of regular propene sequences, inducing crystallization of the γ form at low octene concentrations, lower than 2 mol%. At higher octene concentration, the crystallization of the kinetically favored α form prevails.The crystallization behavior of random propene-octene isotactic copolymers (iPPC8) prepared with a homogeneous metallocene catalyst has been studied. Samples of iPPC8 with low octene content up to about 7 mol% were isothermally crystallized from the melt at various crystallization temperatures. The samples crystallize in mixtures of the α and γ forms of isotactic polypropylene (iPP). The relative amount of γ form increases with increasing crystallization temperature, and a maximum amount of γ form ( Copolymerization of propene with other α-olefins of different chain lengths to isotactic random copolymer is a well know strategy to modify the molecular structure and physical properties and mechanical behavior of isotactic polypropylene (iPP) and expand the possible applications of iPP ,2,3. TheThe effect of comonomers on the crystallization behavior of iPP and crystallization of the different polymorphic forms has been extensively investigated in samples prepared either with heterogeneous Ziegler–Natta catalysts ,31,32,33The α form is the stable form of iPP and generally crystallizes in the common conditions of crystallization from solution or from the melt and in fibers ,94.In standard highly stereoregular samples of iPP synthesized with heterogeneous Ziegler–Natta catalysts, the γ form has been observed only in low molecular mass samples , in coporr triads) or regioregularity   +  + [octene], and compared with the values of fγ(max) observed and found in the literature for highly stereoregular iPP homopolymer . I. Ifγ first increases, achieves the highest value of nearly 90–95% and then decreases with further increase of comonomer concentration (fγ(max) with the comonomer concentration are, however, different in these copolymers. For low defects concentration (lower than 2–3 mol%), the increase of fγ(max) observed in iPPC8 copolymers is faster than that in iPPC6, iPPC5, and iPPC4 copolymers, whereas the increase of fγ(max) observed in iPPC6 copolymers is faster than that in iPPC5 and iPPC4 copolymers, and, finally, the increase of fγ(max) in iPPC5 copolymers is, in turn, faster than that in iPPC4 copolymers (fγ(max) is, indeed, observed for iPPC8 copolymers characterized by the largest size comonomer. Moreover, the highest values of fγ(max) in iPPC5 and iPPC6 copolymers are obtained soon for low pentene and hexene concentrations (2–3 mol%), whereas in iPPC8 copolymers is achieved at the lowest comonomer concentration of 1.9 mol% (Different behaviors are instead observed in ntration . The ratpolymers . The fas1.9 mol% . Furtherfγ(max) decreases in the three copolymers iPPC4, iPPC5, and iPPC6 down to fγ(max) = 0, corresponding to crystallization of the pure α form. The decrease of fγ(max) in iPPC6 copolymers is faster than in iPPC5 copolymers, which is, in turn, faster than in iPPC4 copolymers. In the case of iPPC8 copolymers, the decrease of fγ(max) from the highest value is faster than in iPPC6, iPPC5 and iPPC4 copolymers, because the value of fγ(max) = 50% is obtained already for the sample with 7.1 mol% of octene, which gives only a disordered modification of γ form with structure intermediate between those of the α and γ forms (fγ(max) starts at concentrations of comonomers of 2 mol% for iPPC8 copolymers, nearly 4–5 mol% in iPPC6 copolymers, 10–11 mol% in iPPC5 copolymers, and 14–15 mol% in iPPC4 copolymers  of LiPP>. For the different copolymers, different relationships between <LiPP> and fγ(max) have been obtained [The two competing effects of interruption of the regular propene sequences of defects excluded from the crystals and the inclusion of defects into crystals define the crystallization behavior of iPP. The interruption effect induces crystallization of γ form ,93,110, obtained ,93,110, fγ(max) and <LiPP>, which essentially corresponds to the interruption effect [rr stereodefects are mainly excluded from crystals , and the effect of interruption and of shortening the length of the regular propene sequences prevails [LiPP> and decreases with increasing octene concentration and decreasing <LiPP>. This is due to the fact that the long octene units makes the crystallization of the γ form too much slow even for short values of <LiPP>, inducing crystallization of the kinetically favored α form, and prevents complete crystallization of both α and γ forms at octene concentrations higher than 12–13 mol%.The plot of n effect ,110. Ethprevails ,110. Forfγ(max) and <LiPP> (LiPP> of 200-30 monomeric units), the included amounts of pentene and hexene are low, as in the case of ethylene, and the effect of interruption prevails inducing crystallization of the γ form. The bigger the comonomer, the more efficient the interruption effect, and the higher the amount of γ form. In fact, for this composition, iPPC5 and iPPC6 copolymers give an amount of γ form higher than those of iPPC2 copolymers and defective iPPs but lower than that of iPPC8 copolymers  LiPP> lower that 20–30 monomeric units, hexene, pentene, and butene units are incorporated in the α form to very high extents with corresponding increase of crystalline density, and the inclusion effect with the stabilization of the α form prevails over the interruption effect, inducing the crystallization of the α and δ forms, with a fast decrease of the maximum amount of γ form down to zero for iPPC6, iPPC5, and iPPC4 copolymers (fγ(max) depends on the fast or slow increase of crystal density, which depends on the size of the included comonomer. Therefore, the decrease of fγ(max) is faster in iPPC6 copolymers because of the bigger hexene units, and the decrease of fγ(max) in iPPC5 copolymers is faster than that of iPPC4 copolymers. It is worth noting that the fastest decrease of the maximum amount of γ form in iPPC8 copolymers is not due to incorporation of octene units in the crystals of α form, but, as mentioned above, is rather correlated to the fact that the excluded octene units make the crystallization of γ form too slow, inducing the faster crystallization of the kinetically favored α form, and then, at high concentrations, completely prevents crystallization of both α and γ forms (For comonomer concentrations higher than 5 mol% and <polymers  [72,74,9 γ forms .These data on iPPC8 copolymers and the comparison with the literature demonstrate that the crystallization behavior of iPP may be described in terms of a model that defines a double role exerted by defects, the interruption of the regular propene sequences, and the inclusion effect. The crystallization of α, γ, and δ forms of iPP depends on which effect prevails, which in turn depends on the size and type of the defect.Random isotactic propene–octene copolymers with octene concentrations ranging from 1.9 to 16 mol% have been synthesized with a homogeneous single center metallocene catalyst. The as-polymerized samples with octene content up to 10–12 mol% crystallize in the α form of iPP, whereas for higher octene concentration, the samples are basically amorphous or show very low crystallinity. The melting temperatures decrease with increasing octene content from 132 °C of the sample with 1.9 mol% of octene down to 47–45 °C for the samples with 12.8 and 15.9 mol% of octene.Three samples of iPPC8 copolymers with low octene concentration of 1.9, 4.3, and 7.1 mol% have been isothermally crystallized from the melt at different crystallization temperatures. The samples crystallize at any crystallization temperature in mixtures of α and γ forms and the relative amount of γ form increases with increasing crystallization temperature and achieves a maximum value, which depends on the octene concentration. Contrary to propene–pentene and propene–hexene copolymers that, for high concentrations of pentene and hexene, crystallize in the δ form ,93, the The behavior of iPPC8 copolymers is completely different from the behaviors observed in iPPC2 , iPPC4 , iPPC5 , and iPPIn copolymers of iPP with butene, pentene, and hexene, the comonomer units are, instead, incorporated in the crystals of α form to a very high extent. At a high concentration of comonomers, the inclusion effect that favors crystallization of the α form prevails over the interruption effect. The efficiency of the incorporation effect depends on the size of comonomers, as a rapid or slow increase of density is obviously correlated to the size of the incorporated comonomer.For iPPC8 copolymers, the observed fastest decrease of the maximum amount of γ form and the consequent crystallization of the α form for high octene concentrations is not due to incorporation of octene units in the crystals of α form, but is due to the fact that the excluded octene units make the crystallization of γ form too slow, inducing the faster crystallization of the kinetically favored α form and, then, at high concentration, prevent the crystallization of both α and γ forms.The reported results on crystallization of iPPC8 copolymers and the comparison with the literature demonstrate that the crystallization behavior of iPP may be described in terms of a model that defines two effects exerted by defects: the interruption of the regular propene sequences and the inclusion effect. The crystallization of α, γ, and δ forms of iPP depends on which effect prevails, which in turn depends on the size and type of the defect.


The authors regret that an incorrect version of 37 The peak at 531.3 eV is attributed to oxygen in absorbed water, and the binding energy at 532.2 eV is attributed to the oxygen atoms on defect atoms.37” This text should read, “The binding energy at 530.1 eV and 531.3 eV corresponds to the oxygen atom coordinated with a metal atom (Sn–O–Sn) and (Sn–O–Zn),37 and the binding energy at 532.2 eV is attributed to the hydrated species O–H.36”The authors regret that there was an error in the text in lines 5–10 in the right column on page 31987 of the original article. The text originally read, “The binding energy at 530.1 eV and 531.3 eV belongs to the oxygen atom coordinated with a metal atom (Sn–O–Sn) and (Sn–O–Zn), respectively.The Royal Society of Chemistry apologises for these errors and any consequent inconvenience to authors and readers.


Synthesis, crystal structure determination by single‐crystal and powder X‐ray diffraction methods, as well as 6Li, 31P and 119Sn MAS NMR and temperature‐dependent 7Li NMR spectroscopy together with electrochemical impedance studies are reported. The correlation between the ionic conductivity and the occupation of octahedral and tetrahedral sites in a close‐packed array of P atoms in the series of compounds is discussed. We conclude from this series that in order to receive fast ion conductors a partial occupation of the octahedral vacancies seems to be crucial.The targeted search for suitable solid‐state ionic conductors requires a certain understanding of the conduction mechanism and the correlation of the structures and the resulting properties of the material. Thus, the investigation of various ionic conductors with respect to their structural composition is crucial for the design of next‐generation materials as demanded. We report here on Li 5SnP3The compound Li completes for x=0 the series Lix10+4Snx2−P6 (x=0–1) of lithium‐ion conducting phosphidostannates. The thorough investigation of the crystal structure as well as the materials properties applying X‐ray diffraction as well as NMR and electrochemical impedance spectroscopy allows for a detailed comparison of the materials structure‐property relationships, and thus, improves the understanding of the conduction mechanism within solid ion conductors. Solid‐state electrolytes (SE) are predicted to dominate mainly in electric vehicles and future lithium battery chemistry.−3 S cm−1 have been reported[3P3 shows moderate electric conductivity and an unprecedented stability when exposed to water and air.TtP4] or [TrP4] units, which occur either as isolated [TtP4]8− or [TrP4]9− anions that are charge‐compensated by the corresponding amount of Li+ or they build frameworks of condensed tetrahedra and supertetrahedra, respectively. units resulting in the polyanion [Si2P6]10−.10Si2P6 rather than Li5SiP3 to express the molecular‐anionic character. Indeed, a compound with the composition Li5SiP3 has been reported in the 1950s, and characterized by the determination of the cubic space group Fm3‾m with a lattice parameter of a=5.852 Å.3Bi structure,ccp of P atoms in which all tetrahedral voids are statistically occupied by Li+ and Si4+ in a mixing ratio of 5 : 1. So far, all attempts to reproduce these findings have failed.. In analogy to the structures of α‐ and β‐Li8SnP4 and Li14SnP6, respectively, the Sn atoms are occupying tetrahedral voids, resulting in SnP4 units.10−. Such units are also observed in the homologous lithium phosphidosilicate Li10Si2P6.2P6]10− units are not ordered, and thus, the chemically different P atoms do not appear with a distinct difference in the chemical environment. A further resolution of the broad signal in order to distinguish P atoms located next to only one Sn atom (1b‐P2−) and P atoms surrounded by two Sn atoms (2b‐P1−) was not feasible. Possible reasons are given after the discussion of the 119Sn NMR spectrum.The 119Sn NMR spectrum of Li5SnP3, the high level of cation disorder also results in only one very broad (∼13 kHz) tin resonance at a chemical shift of 124.6 ppm . In analogy to the 31P NMR measurements, this effect has also been observed in the 119Sn spectrum of Li14SnP6.5SnP3 shows a downfield shift of 26.5 ppm, and the resonances of the lithium phosphidostannates Li5SnP3, α‐ and β‐Li8SnP4 and Li14SnP6 shown in Figure Regarding the 14SnP6 shows both, [SnP4]8− and P3− units, whereas the two modifications of Li8SnP4 only contain [SnP4]8− tetrahedra, and the basic structure of Li5SnP3 consists of [Sn2P6]10− units.[4] tetrahedra in Li5SnP3, which are correspondingly reported for Li10Si2P6. In contrast to the strongly covalent character of the Si−P bonds leading to molecule‐like [Si2P6] units5SnP3 is assumed to be mainly dominated by the ionic character of the Sn−P bonds resulting in much weaker bonds and, thus, in more uniform chemical environments.Regarding the electron‐precise stoichiometry of the so far known lithium phosphidostannates the structure of Li0− units.7, 8 T6Li MAS NMR spectrum shows only one signal corresponding to the one Li site in the structure. The chemical shift of δ=4.2 ppm occurs within the characteristic range of 6Li resonances reported for lithium phosphidotetrelates and ‐trielates. tetrahedra in Li5SnP3, which in accordance with the charge are expected to form edge‐sharing [Sn2P6]10− dimers as found as ordered variant in Li10Si2P6.The systematic investigation of the ternary Li/Sn/P system within the formula LiA two‐step synthesis route, including mechanical alloying and subsequent annealing of the samples, yields all four compounds in high purity and on a gram scale allowing for a profound determination of the properties.σLi=3.2(2) ⋅ 10−7 S cm−1 of Li5SnP3 in combination with vacant octahedral sites on the one hand, and the high ionic conductivity of α‐ and β‐Li8SnP4 as well as of Li14SnP6 with partially filled octahedral sites on the other unequivocally proof the importance of the participation of the octahedral voids in ion motion. In order to lower the activation energy one can either lower the energy barrier for Li+ motion between neighboring sites or raise the energy level of the respective sites. The partial occupation of the energetically unfavorable octahedral voids in the Li‐rich phosphidotetrelates corresponds to the latter case and leads to an overall flattening of the energy landscape. In this context the investigation of less promising Li+‐conducting materials with insufficient ionic conductivities for application, plays a key role in the understanding of the criteria to design and tailor next‐generation ionic conductors.The low ionic conductivity of 5SnP3, details on the investigation of the system Lix8−4Snx1+P4 (x=−0.333 to +0.333), differential scanning calorimetry (DSC), 6Li, 119Sn, and 31P MAS NMR spectroscopy.Details of crystal structure determination of LiThe authors declare no conflict of interest.1As 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.Supporting InformationClick here for additional data file.