Mycoplasma hyopneumoniae at three independent locations.This field trial was designed to evaluate the efficacy of a new trivalent vaccine containing porcine circovirus type 2a and 2b (PCV2a/b), and M. hyopneumoniae co‐infection. Each farm housed a total of 60, 3‐day‐old pigs that were randomly allocated to one of three treatment groups. Pigs were administered the trivalent vaccine intramuscularly with either a 1.0 ml dose at 3 and 24 days of age or a 2.0 ml dose at 21 days of age in accordance with the manufacturer's recommendations.Three farms were selected based on their history of PCV2 and p < 0.05) than those of unvaccinated animals during the growing (70–112 days of age), finishing (112–175 days of age) and overall (3–175 days of age) stages of production. One‐dose and two‐dose vaccinated animals elicited neutralizing antibodies and interferon‐γ‐secreting cells (IFN‐γ‐SC), which reduced the amount of PCV2 in terms of blood load and reduced the severity of lymphoid lesions when compared with unvaccinated animals. Similarly, one‐dose and two‐dose vaccinated animals elicited IFN‐γ‐SC, which reduced the amount of M. hyopneumoniae in terms of laryngeal load and reduced the severity of lung lesions.Clinically, the average daily weight gain of the one‐dose and two‐dose vaccinated groups within all three farms was significantly higher , and Mycoplasma hyopneumoniae at three independent locations. It is a primary etiologic agent of ‘porcine circovirus–associated disease’ (PCVAD)  along with M. hyopneumoniae  has been introduced into the Asian market. The trivalent vaccine is of particular interest because it contains PCV2b, which is genetically close to PCV2d. Although PCV2a‐based vaccines may protect pigs against PCV2d  on all three farms was stable, with no active PRRSV circulation . All replacement gilts used in the three farms tested seronegative for Each farm consistently suffered pig loss over several months due to growth retardation and respiratory disease in the late post‐weaning and growing stages. Clinical signs first appeared at approximately 7–10 weeks of age and reached peak mortality  between 10 and 15 weeks of age.10 DNA copies/ml ranged from 2.35 to 3.23 from farm A and 2.45 to 3.32 from farm B. These values were consistent with the definition of subclinical PCV2 infection . QIA protocols mandate that a total of 20 pigs were assigned to each study group. Study design considerations included randomization, personnel blinding and that animals were both weight‐matched and sex‐matched under a controlled clinical field trial format. To minimize sow variation, either six or nine, 3‐day‐old pigs were randomly selected from seven total sows. If six (or nine), 3‐day‐old pigs were pulled from a sow, two (or three) pigs were assigned to each of three uniform study groups. A total of 180 pigs were used for the entire study. Sixty pigs per farm were randomly divided into three groups within each farm  using the random number generator function  . Each farm received a different serial of the vaccine as follows: Farm A = Serial No. 395164A, Expiration date: 10 December 2021, Farm B = Serial No. 394687A, Expiration date: 10 December 2021 and Farm C = Serial No. 413369A, Expiration date: 03 February 2022. Pigs in the VacA2, VacB2 and VacC2 groups were injected intramuscularly in the right side of the neck at study days 0 (3 days of age) and 21 (24 days of age) with 1.0 ml of the trivalent vaccine. Pigs in the UnVacA, UnVacB and UnVacC groups were injected intramuscularly in the right side of the neck at study days 0 (3 days of age) and 21 (24 days of age) with 1.0 ml of phosphate‐buffered saline .The pigs in the VacA1, VacB1 and VacC1 groups were injected intramuscularly in the right side of the neck at study day 18 (21 days of age) with 2.0 ml of the trivalent vaccine containing PCV2a/b and At 28 days of age, pigs from the vaccinated and unvaccinated groups were commingled and randomly assigned into six pens (10 pigs per pen) using the random number generator function . All pens were identical in design with equipment including free access to water and feed. Five pigs from each group were randomly selected and euthanized for necropsy at 112 days of age. The rest of pigs from each group were euthanized for necropsy at 175 days of age. Pigs were sedated by an intravenous injection of sodium pentobarbital and then euthanized by electrocution as previously described , 18 (21 days of age), 46 (49 days of age), 67 (70 days of age) and 109 (112 days of age). Pigs were snared and restrained with a mouth gag for laryngeal swab collection. Swabs were guided with a laryngoscope down into the larynx. The internal walls of the laryngeal cartilages were then swept with the swabs once the larynx was visualized and the epiglottis was in a low position as previously described , 18 (21 days of age), 67 (70 days of age), 109 (112 days of age) and 172 (175 days of age). ADG (g/pig/day) was determined for study days 0–18, 18–67, 67–109 and 109–172. The ADG during these various production stages was calculated as the difference between the starting and final weight divided by the duration of the stage. Data for dead or removed pigs were included in the calculation.2.710 to 102 copies/ml, and (ii) 10‐fold serial dilutions of PCV2 cultured in PCV1‐free PK‐15 cells were used at concentrations ranging from 104.5 TCID50/ml to 10−3.5 TCID50/ml. The PCV2 plasmid was prepared as described previously  was used to extract DNA from serum samples for PCV2d. The number of genomic DNA copies for PCV2a, PCV2b and PCV2d was then quantified by real‐time PCR  to quantify the M. hyopneumoniae strain SNU98703, with concentrations ranging from 10 ng/μl to 1 fg/μl. One femtogram of chromosomal DNA from M. hyopneumoniae is considered to be approximately one genome equivalent  and M. hyo Ab test ]. Testing was conducted in accordance with each manufacturer's kit instructions, where samples were considered as positive for anti‐PCV2 antibodies if the reciprocal ELISA titre was >350 and as positive for M. hyopneumoniae antibody if the sample‐to‐positive (S/P) ratio was ≥0.4.The presence of PCV2 and 2.Serum samples were tested for serum virus neutralization using PCV2d strain    in RPMI 1640 medium supplemented with 10% fetal bovine serum  were seeded into plates precoated overnight with anti‐porcine IFN‐γ monoclonal antibody  and incubated with PCV2d (20 mg/ml), M. hyopneumoniae (4 mg/ml) or phytohemagglutinin  as a positive control or PBS as a negative control for 20 h at 37°C in a 5% humidified CO2 atmosphere. The wells were washed five times with PBS (200 ml per well) and thereafter, the procedure followed manufacturer's instructions using commercial ELISpot assay kit (MABTECH). The spots on the membranes were read by an automated ELISpot reader . The results were expressed as the number of responding cells/million PBMC.An enzyme‐linked immunospot (ELISpot) assay was conducted to measure the numbers of PCV2d‐ and 2.11Two pathologists at the Seoul National University scored the severity of macroscopic lung lesions in order to estimate the percentage of the lung affected by pneumonia . PCV2 analysis was conducted by the random selection of 10 microscopic areas, where the number of positive cells per unit area (0.95 mm2) was determined as previously described  was used to examine differences in variables with normal distribution . Kruskal–Wallis test was used for variables without a normal distribution  for groups. If a one‐way ANOVA test resulted in a statistical significance, data were further evaluated by conducting a post hoc test for a pairwise comparison with Tukey's adjustment. Kruskal–Wallis test results which showed a statistical significance were further evaluated with the Mann–Whitney test to include Tukey's adjustment to compare the differences among the groups. Results were reported in p‐value where a value of p < 0.05 was considered to be significant.All real‐time PCR data and neutralizing antibody titres were transformed to log33.1M. hyopneumoniae in unvaccinated animals. Mortality at Farm A was reported as follows: One pig from the VacA1 group died of streptococcal meningitis caused by Streptococcus suis at study day 80 (83 days old). Two pigs from the VacA2 group died of streptococcal meningitis caused by S. suis at study day 72 (75 days old) and suppurative bronchopneumonia caused by Staphylococcus aureus at study day 91 (94 days old), respectively. Two unvaccinated pigs died of enzootic pneumonia caused by M. hyopneumoniae and Pasteurella multocida at study day 64 and 91 (67 and 94 days old), respectively, and one unvaccinated pig died of PCVAD and Glasser's disease caused by Glaesserella parasuis at study day 113 (116 days old).The overall mortality rate is summarized in Table P. multocida at study day 57 (60 days old). Two unvaccinated pigs died of severe respiratory disease caused by PCV2d and M. hyopneumoniae at study day 82 (85 days old) and enzootic pneumoniae caused by M. hyopneumoniae and P. multocida at study day 102 (105 days old), respectively. One unvaccinated pig died of lymphoid depletion caused by PCV2d and fibrinous pleuritis and pericarditis caused by G. parasuis at study day 93 (96 days old).Mortality at Farm B was reported as follows: One pig from the VacB2 group died of pneumonic pasteurellosis caused by S. aureus at study day 50 (53 days old). Two unvaccinated pigs died of enzootic pneumoniae caused by M. hyopneumoniae and S. aureus at study day 61 and 68 (64 and 71 days old), respectively. Two additional unvaccinated pigs died of severe respiratory disease caused by PCV2d and M. hyopneumoniae at study day 65 and 84 (68 and 87 days old), respectively.Mortality at Farm C was reported as follows: One pig from the VacC1 group died of suppurative bronchopneumonia caused by 3.2p < 0.05) clinical sign scores when compared with unvaccinated animals (UnVacA) at study days 60–74  clinical sign scores when compared with unvaccinated animals (UnVacB), but at study days 46–81  clinical sign scores when compared with unvaccinated animals (UnVacC) at study days 39–116  from farm A had significantly lower  body weight when compared with unvaccinated pigs in all farms (A–C) at study day 172 (175 day of age) (Table The body weight of pigs at study days 0 (3 days of age) and 21 (24 days of age) did not differ significantly between vaccinated and unvaccinated group at the time of vaccination on all three farms. Vaccinated pigs  had a significantly higher (p < 0.05) ADG at study days 67–109 (70–112 days old) and 109–172 (112–175 days old) when compared with unvaccinated pigs from the same farm. Overall (study days 0–172), the difference between vaccinated and unvaccinated groups was significant (p < 0.05) on all farms  had significantly higher (ms Table . There w3.4p < 0.05) number of genomic copies of PCV2d in their blood when compared with unvaccinated pigs (UnVacA and UnVacB) at study days 46, 67 and 109. Farm C vaccinates (VacC1 and VacC2) also had a significantly lower (p < 0.05) number of genomic copies of PCV2d in their blood when compared with unvaccinated pigs (UnVacA and UnVacB) at study days 67 and 109. Two‐dose vaccinated pigs (VacC2) from farm C had a significantly lower (p < 0.05) number of genomic copies of PCV2d in their blood when compared with unvaccinated pigs (UnVacC) at study day 46  from farms A and B had a significantly lower  number of genomic copies of M. hyopneumoniae in their laryngeal swabs when compared with unvaccinated pigs  at study days 67 and 109  from three farms had a significantly lower  PCV2 ELISA IgG titre at study day 18 when compared with one‐dose vaccinated  and unvaccinated  pigs. Vaccinated pigs  from three farms had a significantly higher (p < 0.05) PCV2 ELISA IgG titre at study days 46, 67 and 109 when compared with unvaccinated pigs  PCV2 neutralizing antibody titre at study days 46, 67 and 109 when compared with unvaccinated pigs  from three farms had a significantly higher  number of PCV2d‐specific IFN‐γ‐SC at study day 18 when compared with one‐dose vaccinated  and unvaccinated  pigs. Vaccinated pigs  from three farms had a significantly higher (p < 0.05) number of PCV2d‐specific IFN‐γ‐SC at study days 46, 67 and 109 when compared with unvaccinated pigs  from three farms had a significantly higher  M. hyopneumoniae ELISA S:P ratio at study days 46, 67 and 109 when compared with unvaccinated pigs   from three farms had a significantly higher  Figure .p < 0.05) number of M. hyopneumoniae‐specific IFN‐γ‐SC at study day 18 when compared with the unvaccinated pigs. Vaccinated pigs  from three farms had a significantly higher (p < 0.05) number of M. hyopneumoniae‐specific IFN‐γ‐SC at study days 46 and 67 when compared with unvaccinated pigs   from farms A and B had a significantly higher  Figure .3.8p < 0.05) macroscopic lung lesion score, microscopic lung and lymphoid lesion scores and number of lymphoid PCV2‐positive cells when compared to unvaccinated pigs  at study day 109 (Tables p < 0.05) microscopic lung and lymphoid lesion scores, and number of lymphoid PCV2‐positive cells when compared to unvaccinated pigs  at study day 172  from three farms had significantly lower , where the effect of vaccination on the reduction of lung lesion severity was proven. Commercial farm pigs used as field trials such as this are continuously exposed and re‐exposed to the prevalent field PCV2d and M. hyopneumoniae by horizontal transmission. Natural co‐infections as well as other intrinsic and extrinsic factors also exacerbate disease in these less‐controlled commercial settings. A true evaluation of the direct effect of vaccination on pathological outcomes would require a controlled experimental challenge study.Pathological evaluation was also critical in evaluating the protective index as lesion reduction is related to growth performance in both PCV2 and M. hyopneumoniae was proven as effective in piglets less than 1 week of age regardless of MDA presence  present at the time of vaccination. In general, early vaccination against PCV2 and The authors declare no conflict of interest.Hyungmin Um conceptualized the idea of the study, curated the data, performed investigation and designed the methodology. Siyeon Yang curated the data, provided resources and performed visualization. Taehwan Oh designed the methodology and provided software. Hyejean Cho performed formal analysis. Kee Hwan Park performed validation. Jeongmin Suh provided software. Chanhee Chae conceptualized the idea of the study, administered the project, performed supervision and reviewed and edited the manuscript.All of the methods were previously approved by the Seoul National University Institutional Animal Care and Use, and Ethics Committee . Sample collection was carried out according to the animal welfare code of Korea.5https://publons.com/publon/10.1002/vms3.657.The peer review history for this article is available at


The 20‐cycle ALD Al2O3 coated AC delivers 84 % capacitance retention after 1000 charge/discharge cycles under 4 V, contrary to the bare AC cells having only 48 % retention. The extended cycling life is associated with the thickened Stern layer and suppressed oxygen functional group. The self‐discharge data also show that the Al2O3 coating enables AC cells to maintain 53 % of charge retention after 12 h, which is more than twice higher than that of bare AC cells under the same test protocol of 4 V charging. The curve fitting analysis reveals that ALD coating induced slow self‐discharge dominated by ion diffusion mechanism, thus enhancing the AC surface energy.Designing high voltage (>3 V) and stable electrochemical supercapacitors with low self‐discharge is desirable for the applications in modern electronic devices. This work demonstrates a 4 V symmetric supercapacitor with stabilized cycling performance through atomic layer deposition (ALD) of alumina (Al 4 V symmetric supercapacitors are stabilized through optimizing Atomic Layer Deposition of Al2O3 on activated carbon electrodes. The thickened Stern layer and suppressed oxygen functional group extend the cycling life at 4 V. The additional aluminum oxide layer enhances the energy barrier for ion desorption, thereby resulting in a decreased rate of self‐discharge. Too thick oxide coating blocks the nanopores and lower the cycling performance. However, attempts to increase the voltage window, energy density, and cycling stability failed.In the last 20 years, the commercial electrochemical supercapacitor market is being dominated by activated carbonaceous materials (AC), because of their high surface area, high electric conductivity, temperature stability, excellent cycling stability, and low‐cost manufacturing.2O3 using ALD, the commercial AC electrode exhibited an operating voltage of ∼3.5 V in EDLC cells with organic electrolytes.2O3 modification even enabled the graphene supercapacitor cells to reach up to 4.4 V.An alternative way to increase the cell voltage is to stabilize the electrolyte and electrochemically active surface functional groups at the porous carbon surface. Using purer AC synthetic process to remove oxygen‐containing terminating groups from the porous carbon surface has led to introduction of commercial cells rated at 3 V. Passivating the surface of AC electrodes using a metal oxide much boosted the EDLC performance to 3.5 V in the lab.2O3 coating. We demonstrate that high cycle life and low self‐discharge operating at 4 V can be achieved without the use of high end and costly electrolytes.Resolving these technical issues will provide a significant understanding and will influence the introduction of ACs in high‐performance supercapacitor. In this communication, we report on surface modification of commercial AC electrodes by ALD of Al2O3 was carried out using GEMSTAR XTTM ALD system at 150 °C chamber temperature between 2 and 100 cycles using Trimethyl aluminum (TMA) and H2O  as precursors at a constant argon gas flow rate of 10 sccm.2O3.Using commercial YP‐50F AC powder, the authors fabricated the AC electrodes on Al foils using the doctor blade technique through automatic thin‐film coater (MTI corporation). Later, it was vacuum dried for 12 h at 80 °C, and the thickness of the coated AC film was 100 μm. The ALD of Al22.12O3 layer is barely observed on the surface of AC , as shown in Figure C Figure a; howeve2.24/acetonitrile organic electrolyte at 3.5 V and 4 V (at a current density of 50 mA cm−2) by varying the thickness of ALD coating.The AC based supercapacitors suffers from the electrolyte decomposition during electrochemical cycling, especially at the high voltages and elevated temperatures due to undesirable parasitic side‐chain reactions between electrolyte and abundant surface‐active functional sites of electrode material.7b, 8 2O3 coating appears to be in the range of 10 to 50 cycles of ALD for enhanced capacitance retention, which did not block the AC‘s micropore channels. As is shown in Figure HK) method for micropore size distribution analysis reveals that a similar pore width of 0.4 nm and peak position occur, although the peak intensity of bare AC is slightly decreased after 50 cycle ALD Al2O3 coating. This pore structure implies a minimal blockage of micropores until 50 cycles ALD coating, but not a significant blockage. Similar trend in cycle life performance upon increasing ALD cycle is observed at 4 V, where bare AC shows only 48 % capacitance retention till 1000 GCD cycles, whereas the AC cell with 20 cycles ALD shows the highest capacitance retention of 84 %. Further increasing the ALD cycle number beyond 20 cycles, the cyclic retention decreased, as shown in Figure At 2 cycles (∼0.2 nm), the improvement of retention shows to be limited and ends up at the same level as the bare AC electrodes , most of the nanopores are blocked, evidenced by the significant decrease in the pore volume  mechanisms and these are explained by the linear dependence of cell potential vs logarithmic time, cell potential vs square root time, and ln potential vs time, respectively. These mechanisms often co‐occur but dominate in different time regions.11 Figur1/2 according to Eq. To explain the diffusion‐controlled mechanism, the self‐discharge curves display a linear relation between V and t−2 V s−1, which is much larger than that of 20‐cycle ALD Al2O3. This may be understood as the suppression and passivation of surface functionalities of AC by thickened ALD coating, which inhibits the undesirable faradaic redox reactions between ions and surface functionalities of AC. Electrochemical impedance spectroscopy (EIS) analysis was taken for AC electrodes with and without ALD Al2O3 coating to show how the coating affects the impedance. Figure 2O3 coating (lower impedance observed for 2 nm thick Al2O3). Yet, the Al2O3 coating changed the AC surface chemistry and the diffusion path of ions with respect to the baseline AC.Where m is the diffusion parameter corresponding to the diffusion rate of the ions near the electrode surface. By fitting the data in Figure 2O3 on the AC surface as shown in Figure 2O3 as revealed by our own XPS analysis.During the charging process, the ions from electrolytes are adsorbed on the surface of the ACs until it gets fully charged. The ions have to overcome a free energy barrier displayed in Figure k) and Gibbs free energy of activation (ΔG≠), which can be derived from the rate constant based on transition state theory using the Eyring equation:Self‐discharge based on ion desorption can be written as a chemical reaction of A→B, where A denotes the absorbed ion and B is the free ion Figure b. This f is the transmission coefficient , kB the Boltzmann constant (1.38×10−23 J K−1), h the Planck constant (6.626×10−34 J K−1), R the universal gas constant (8.314 J mol−1 K−1) and T is the absolute temperature (293 K). The Ohmic leakage mechanism has the same linear relationship as for a first‐order reaction having a gradient equal to k. This rate constant (k) of bare AC and 20‐cyle ALD Al2O3 coated AC can be obtained from the slope as shown in Figure −6 s−1 yielded a ΔG≠=101,109 J mol−1, whereas the 20‐cyle ALD coated AC has the k=3.70×10−6 s−1 yielded a ΔG≠=102,180 J mol−1. Increase in the free energy of activation over 1 kJ mol−1 from ALD coating implies that the additional dielectric layer enhances the energy barrier for ion desorption, thereby results in a decrease in the rate of self‐discharge.Where, 32O3 on commercial AC surface. The investigation of ALD Al2O3 coating revealed the effective working thickness range of 1–5 nm (10–50 ALD cycles) for significantly stabilizing the cycling performance at 4 V. The enhanced voltage is attributed to the Al2O3 coating effect, however, is not proportional to the coating thickness. Too thick oxide coating (10 nm) blocked most of the nanopores and thus lowered the cycling performance of capacitance. The Al2O3 coating may act as the spacer separating the electrolyte ions from the AC, which not only suppressed the adverse effect of oxygen functional group on the original AC electrodes, but also enabled higher voltages through the thickened Stern layer. The self‐discharging experiment and data analysis indicated that ALD oxide coating could eliminate the overpotential issue for the AC electrode when operating at 4 V and slow down the ion diffusion rate. The ALD coating also increased the free energy of activation by 1 kJ mol−1 as compared to that of the bare AC cells, which may be attributed to the enhanced surface energy or electrolyte wettability against ion desorption.In conclusion, we have systematically investigated the ALD coating effect on the AC′s supercapacitor performance using cycle life, cyclic voltammetry, and galvanostatic charge‐discharge. We have achieved 4 V capability in AC‐based EDLCs through optimizing ALD thickness of AlThe 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.


The first C5 polymerization is reported, where the main‐chain is growing by five carbon atoms of the monomer at a time. Three dienyltriphenylarsonium ylide monomers were synthesized and polymerized with triethylborane as an initiator, leading to random terpolymers  with mainly C5 repeating units (up to 84.1 %). It has been found that the methyl group (electron‐donating substituent) on the conjugated double bond of the ylides facilitates the formation of C5 segments. A mechanism was proposed based on NMR characterization and DFT calculations. The high C5 content ensures that things are on the right track for pure C5 homopolymerization. Reported for the first time is an unusual borane‐initiated polymerization of arsonium ylide monomers, where the main‐chain grows by five carbon atoms, from the monomer, at a time and leads to unique structures. The development of new polymerization methods is an endless temptation for polymer chemists because it provides access to new polymer structures that will offer unprecedented properties and applications. In 1997, Shea et al. discovered a borane‐initiated living C1 polymerization (chains growth by one carbon atom at a time) of dimethylsulfoxonium methylide and coined the name polyhomologation, a totally different method compared to the traditional polymerization of alkenes (C2 polymerization).3)  Scheme . Interes1H NMR, 13C NMR, 19F NMR, and 1H‐1H COSY  confirmed the structures of the obtained dienyltriphenylarsonium ylide salts. Salt 1 exhibited 88.7 % of E,E‐configuration (trans), while salts 2 and 3 had 100 % E‐configuration. The deprotonation of the salts by n‐butyllithium (n‐BuLi) in tetrahydrofuran (THF) at −78 °C under an argon atmosphere, generated in situ the corresponding ylide monomers . In order to ensure the complete conversion of salts to ylides, the reactions left overnight.Three dienyltriphenylarsonium ylide salts were synthesized and used as precursors of ylide monomers (see Scheme S1 in the Supporting Information). 3, were carried out using various initial molar ratios of ylide 1 to BEt3  in 61–78 % yield. The synthesized polymers were characterized by NMR and size exclusion chromatography (SEC). When the initial molar ratios of ylide 1 to BEt3 was increased from 105/1 to 315/1, the molecular weight of polymers calculated by both NMR and SEC increased steadily. The SEC traces shift from the low molecular weight to high molecular weight elusion volumes, and they are symmetrical, monomodal, and narrow (Đ=1.22–1.27)  Figure . Besides1H NMR spectrum of polymer 1 is shown in Figure 1H NMR varied from 79.7–84.1 %  indicates that the double bonds possess the E‐configuration (trans). By careful analysis of the COSY spectrum , the structure of the terpolymer was further confirmed. It was also observed that the end of polymer 1 is a C5 monomer unit connected to the hydroxyl group, because at the end of the polymerization process, the crowded polymeric organoborane promotes the formation of C5 polymer, which is beneficial for releasing steric hindrance. In addition, continuous C1 or C3 units are never found. This may indicate that the spatial congestion of continuous C1 or C3 units promotes the two  sigmatropic rearrangements.A representative −1, the C5 segment ratio increases from 79.7 to 84.1 %, which indicates that high molecular weight induces an important steric crowding, thus facilitating the formation of C5 segments. When the polymerization of ylide 1 was conducted in a lower molar ratio , polymer 2 and polymer 3 are both random terpolymer with 65.3 % and 62.5 % C5 segments, respectively. The SEC traces are both monomodal and narrow .The BEtCompared to polymer 2 and polymer 3, polymer 1 has the most C5 segments (79.7 %), since the methyl substituent of ylide 1 enhances the electron density of the conjugated double bond, which facilitates the 1,3‐migration on the conjugated double bond. Ylide 2 also has a methyl substituent on the conjugated double bond. Hence, polymer 2 should also have a high C5 segment ratio. However, it is only 65.3 %. This may be attributed to the low polymerization temperature (−40 °C), because ylide 2 is unstable and decomposes above −40 °C. The low polymerization temperature inhibits the  sigmatropic rearrangement to occur. Even so, the C5 segment ratio of polymer 2 is higher than that of polymer 3 (62.5 %). The C5 segment ratio of polymer 3 is the lowest of the three polymers, which further confirms the electronic effect we proposed above. There is no methyl group (electron‐donating substituent) on the conjugated double bond of ylide 3, which reduces the attractiveness of the 1,3‐migration on the conjugated double bond, resulting in a high C1 segment (33.2 %).As summarized in Table In summary, the first C5 polymerization is reported, where the main‐chain is growing by five carbon atoms of the monomer at a time. For this purpose, three new dienyltriphenylarsonium ylides were synthesized and polymerized with an organoborane initiator to afford random terpolymers with predominantly C5 repeating units (up to 84.1 %). The outcome of C5 polymerization depends on the occurrence of  sigmatropic rearrangements, which are related to the substituent of the conjugated double bond of ylides. It has been found that the methyl group (electron‐donating substituent) on the conjugated double bond of ylides facilitates the formation of C5 units. Although the three dienyltriphenylarsonium monomers, synthesized for the first time and used in this study, resulted in random terpolymers, the higher C5 content than C1 and C3 ensures that we are on the right path to pure C5 homopolymerization. Based on these results, we are now designing/synthesizing new ylides and studying their borane‐initiated polymerization.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.


With advanced light‐trapping structures, the Sb2Se3 nanorod array‐based solar cells have excellent broad spectral response properties, and higher short‐circuit current density than the conventional planar structured thin film solar cells. However, the interface engineering for the Sb2Se3 nanorod array‐based solar cell is more crucial to increase the performance, because it is challenging to coat a compact buffer layer with perfect coverage to form a uniform heterojunction interface due to its large surface area and length–diameter ratio. In this work, an intermeshing In2S3 nanosheet‐CdS composite as the buffer layer, compactly coating on the Sb2Se3 nanorod surface is constructed. The application of In2S3‐CdS composite buffers build a gradient conduction band energy configuration in the Sb2Se3/buffer heterojunction interface, which reduces the interface recombination and enhances the transfer and collection of photogenerated electrons. The energy‐level regulation minimizes the open‐circuit voltage deficit at the interfaces of buffer/Sb2Se3 and buffer/ZnO layers in the Sb2Se3 solar cells. Consequently, the Sb2Se3 nanorod array solar cell based on In2S3‐CdS composite buffers achieves an efficiency of as high as 9.19% with a VOC of 461 mV.Antimony selenide (Sb 2S3 nanosheet‐CdS composite buffer layer is constructed and applied in Sb2Se3 nanorod array solar cells, which build a gradient conduction band energy configuration in the Sb2Se3/buffer heterojunction interface. The champion cell based on In2S3‐CdS composite buffers achieves a PCE of 9.19% with an VOC of as high as 461 mV.An intermeshing In Thus, alternative earth‐abundant light‐absorbing materials have been investigated for high efficiency, eco‐friendly, and stable solar cells.Photovoltaic (PV) technologies that directly convert solar radiation into electricity, offer a green and renewable energy to meet the growing demand in the developed world. Among thin film solar cells, great successes have been achieved in copper indium gallium selenide (CIGS), cadmium telluride (CdTe), and perovskites with certified power‐conversion efficiency (PCE) over than 22%.2Se3) has recently emerged as a promising PV absorber material and been receiving more and more research interest due to its favorable material and optoelectronic properties. It exhibits proper bandgap of 1.1–1.3 eV, high absorption coefficient of 105 cm−1 in the visible region, excellent carrier mobility, and good device stability. Moreover, Sb2Se3 is environmentally friendly, and is not in the list of highly materials by US, EU, or Chinese regulation authorities. The abundant of elements Sb and Se in the earth's crust is 0.2 and 0.05 ppm, respectively. Consequently, this makes Sb2Se3 a very promising absorber material for PV application.Antimony selenide  nanoribbon grain structure comprising of covalently bonded (Sb4Se6)n ribbons held together via Van der Waals forces. This unique 1D crystal structure leads to not only the bond anisotropy but also the strongly anisotropy in optical, electrical, and defect properties. For instance, the hole mobility along ribbon (c‐direction) is nearly four times than that cross the ribbons (b‐direction). Thus, control of the crystal orientation of Sb2Se3 grains is the very crucial to the quality of absorber layer and also the device performance of solar cells. Tang's group reported that the strong correction between device performance and the orientation of Sb2Se3 absorber layer. The detailed analysis revealed that the carrier transport in the [221]‐oriented grain n ribbons) was much easier than in the [120]‐oriented grains . They further investigated the effect of ZnO substrate orientation on the orientation and quality of the top Sb2Se3 layer. As a result, highly preferred [221] orientation Sb2Se3 absorber was obtained, and the corresponding superstrate ZnO/Sb2Se3 thin film solar cell demonstrated a high conversion efficiency and good stability under the test condition of International Electrochemical Commission 61 646 protocol. Up to now, most reported Sb2Se3 solar cells are based on [221]‐oriented Sb2Se3 absorber layer with excellent carrier transport property.The most attractive merit of Sb2Se3 nanorod arrays along the [001] direction, where the single crystal Sb2Se3 nanorod consists of titled (Sb4Se6)n ribbons stacked vertically on the substrate. The [001]‐oriented Sb2Se3 grain allows the carrier transport only in the covalent‐bonded ribbons and is beneficial for device performance improvement. In addition, the growth of 1D [001]‐oriented Sb2Se3 nanorod is thermodynamically favorable, and results in no dangling bonds at their grain boundaries (GBs) due to the low formation energies. The potential issue of carrier recombination loss at the GBs could be alleviated for the 1D Sb2Se3 nanorod‐based solar cells, whereas the recombination through dangling bonds at the GBs is the main factor limiting the device performance for traditional 3D ploy‐crystalline thin film solar cells, such as CuInGaSe2, CuInS2, CdTe, CZTS, etc. From this view, the interface recombination, especially occurs at the terminals of the single‐crystal Sb2Se3 nanorod, become dominant for the performance improvement of Sb2Se3‐based solar cells. The Sb2Se3 nanorod array‐based solar cells suffer from higher interface defect density and carrier recombination and thus have more serious open‐circuit voltage deficit than the Sb2Se3 thin film configuration devices. The element interdiffusion at the junction interface is another interesting feature of Sb2Se3/CdS heterojunction solar cells. Williams et al. revealed that an atom scale interfacial layer can unavoidably form at the Sb2Se3/CdS interface due to the rapid interdiffusion of Sb and Se from Sb2Se3, which would increase the interfacial recombination and lead to low device efficiencies. An ultrathin titanium oxide (TiO2) layer deposited by atomic layer deposition (ALD) has been employed to passivate the Sb2Se3 nanorod array‐based heterojunction interface, and an power conversion efficiency (PCE) as high as 9.2% was achieved. The interface engineering was a crucial factor for high efficiency Sb2Se3 solar cells. Vacuum thermal evaporated buffer layer was also employed in the substrate Sb2Se3 devices with following chemical etching and annealing procedure.Recently, we reported the construction of photovoltaic devices based on Sb2S3‐CdS composite buffer layer application in Sb2Se3 nanorod array solar cells. This fabrication procedure is vacuum‐free and low‐cost in comparison with ALD‐TiO2 technique. Meanwhile, the band alignment structure of the heterojunction is another crucial factor that relating to the interface recombination behavior and determining the efficiencies of thin film solar cells. A cliff‐like band offset is observed at the Sb2Se3/CdS interface, which would increase the interface recombination and thus decrease the device VOC. The band structure of In2S3‐CdS composite buffer could be controlled by regulating the deposition of CdS layer. The composite buffer reduces the recombination paths at the heterojunction interface, leading to an increase in recombination activation energy Ea and VOC. Moreover, a gradient conduction band maximum is formed for the In2S3‐CdS composite layer, which is favorable for the transfer and collection of photogenerated electrons. as a result, a PCE of 9.19% is achieved for device based the optimized composite buffer with VOC of 461 mV, JSC of 29.92 mA cm−2 and FF of 66.67%, while the PCE of the standard device with single CdS buffer is 7.39%.In this work, we propose a solution processed In2Figure 2Se3 nanorod arrays (NRAs) were prepared by close spaced sublimation (CSS) technique by subliming the Sb2Se3 powder source onto the surface selenized Mo‐coated glass substrate. The sublimation process continues for tens of seconds and the thickness of Sb2Se3 NRAs is about 1000–1200 nm. Afterward, the Sb2Se3 NRAs were first coated by solution‐processed indium sulfide (In2S3) nanosheet layer, and followed by deposition of cadmium sulfide coating to get the In2S3‐CdS composite buffers. We first check the morphologies and compositions of the In2S3‐CdS composite layers, and the single In2S3 nanosheet layer and single CdS layer were also included for comparison. In this work, the In2S3 nanosheet layer and CdS layer were prepared by hydrothermal deposition and chemical bath deposition (CBD), respectively. The composite layers were controlled by tuning the CdS deposition time between 5 and 11 min, while keeping the In2S3 deposition condition was same for all samples. For description clarity, we denoted the sample coated with hydrothermal In2S3 and CdS buffer for 5 min as C5, and CBD CdS layer for 7, 9, and 11 min as C7, C9, and C11, respectively.As illustrated in Figure 2Se3 NRAs coated with In2S3, In2S3‐CdS composites , and single CdS buffer layers. Obvious nanosheet‐like In2S3 films could be observed on the surface of Sb2Se3 nanorods after the hydrothermal deposition of In2S3 for 100 min  pattern . After deposition of 5 min CdS, the dendritic features of the NRAs become weakened but remain loose nanorod surface , S2−, H+ and other ions, were formed in the reaction aqueous solution by ionization and hydrolysis action from the precursors  in the aqueous solution. β‐In2S3 can be formed under a low concentration of S2− due to its low solubility of 5.7 × 10−74. Citrate ion (C6H7O7−) combines with some of In3+ to reduce the concentration of free In3+ in an acidic solution (pH = 2). In2S3 nuclei can be formed by directly combination of In3+ and S2− under a low concentration. On the other hand, citrate ion could also be combined with some of In3+ to form the indium‐citrate complex ion In(C6H7O7−)3, and play role in controlling the concentration of free In3+ in the solution. This allows the formation of In2S3 nuclei on the Sb2Se3 nanorod surface. Then the nuclei on the nanorod surface grow self‐assembled and gradually to form nanoflakes due to the difference in surface energy of β‐In2S3.This strongly difference in morphology could be ascribed to the different mechanism for the growth of CdS and In The growth of CdS occurs in an alkaline solution consisting of ammonium hydroxide providing ammonia in the solution. The cadmium ions (Cd2+), generated from the cadmium salt, complex with ammonia to form amino‐cadmium complex ion Cd(NH3)42+, controlling the concentration of free cadmium ions. Then, Cd(NH3)42+ complex ion reacts with hydroxide ions to form the adsorbed dihydroxo‐diammion‐cadmium complex [Cd(OH)2(NH3)2]ads on the In2S3 flake or Sb2Se3 nanorod surface. This complex then reacts with thiourea to form the metastable complex [Cd(OH)2(NH3)2SC(NH2)2]ads. The final CdS was formed through decomposition of the metastable complex. In this stage, the formation of CdS is more likely an in situ and conformal growth process. Furthermore, as the reaction time prolonging, the CdS become bigger nanoparticles gradually and closer together to form continuous films, and the growth rate is high in this stage. This could explain that the huge difference in morphology for different deposition time of CdS, as shown in Figure 2Se3/In2S3 nanorod surface maintains the morphology of In2S3 flake  films. As shown, the surface of Sb2Se3 nanorod is covered by a shell of nanoflake film, like prickly tree branches. High‐magnification TEM image in Figure 2S3 nanoflakes are tightly attached to the Sb2Se3 nanorod surface, forming a core–shell nanorod structure. In contrast, after several minutes of deposition of CdS, the prickly‐like nanorod surface became slightly smooth, as shown in Figure 2Se3/In2S3 heterojunction nanorod . Curve fitting was further performed to determine the surface composition and chemical state of Cd, In, and S with different deposition process, as shown in Figure 3/2 and S 2p1/2, respectively, were detected from all the samples. In the Cd 3d core level XPS spectra, the peaks at 405.2 and 411.9 eV, corresponding to Cd 3d5/2 and Cd 3d3/2 of CdS, respectively, were detected from all the samples but the NRAs with only In2S3 coating. In the In 3d spectra, the peaks associating with In 3d5/2 and In 3d3/2 of In2S3, were detected from the In2S3, C5, C7, and C9 samples. The peak intensity decreases with the increase of deposition of CBD CdS layer, suggesting that the growth of CdS not only between the space of In2S3 flakes but also covered on flake surface. Moreover, no obvious peaks corresponding to In 3d are observed for the C11 sample, hinting that the good coverage of CdS layer on the In2S3 nanoflake films.X‐ray photoelectron spectroscopy (XPS) characterization was performed to check the chemical states of the SbEg) can be obtained based on the Tauc equation, and the calculated results are shown in Figure Eg is 2.77, 2.72, 2.44, 2.35, 2.33, and 2.39 eV for single In2S3 nanoflake film, C5, C7, C9, C11, and single CdS film, respectively. At first, we character the surface energy level of the films. The Fermi level, valence band maximum (VBM) of the sample surfaces were obtained by fitting the cut‐off binding energy and long‐tails of the UPS spectra  of the combination of In2S3 and CdS is affected by the element‐content and therefore depend on the CdS deposition time as the In2S3 layer has the same deposition condition for each sample.The UV–vis and ultraviolet photoelectron spectroscopy (UPS) was employed to reveal the band structure of the composite buffer layers. Figure a Figure –j. The cg Figure  and VBM 2S3‐CdS composite films  is not stacked layer by layer, which more likely to be a mixture of In2S3 and CdS. The Sb2Se3 nanorod is first capped by In2S3 nanoflake films with a poor coverage due to the its ion‐by‐ion growth mechanism. Then, the following CdS layer caped both In2S3 nanoflake and the rest of Sb2Se3 nanorod surface to form a mixed buffer layer. As the CdS deposition time was longer than 9 min, the properties of CdS is dominant and the properties of In2S3‐CdS composite buffers vary slightly with the CdS thickness. The surface CBM of the In2S3‐CdS composites could be tuned by regulating the deposition time of CBD‐CdS. It shows a trend of first decreasing, then increasing and then reducing with decreasing the CdS deposition time, suggesting that the interface between In2S3‐CdS composite buffers and Sb2Se3 absorber has a tendency for a spike‐like conduction band offset (CBO).In fact, the In2S3 nanoflake and CdS nanocomposites, we further characterize in detail the in‐depth composition and band structures of the In2S3‐CdS composite layer (C7) by performing the in‐depth XPS and UPS measurement. Figure −1 for Ta2O5), In is clearly detected at the near‐surface region, and Cd and S peaks remain nearly uncharged, indicating that copresence of In2S3 and CdS in the near‐surface region. The In, Cd, and S peaks keep nearly the same intensity as the etching time increases to 375 s. Furthermore, the In and Cd peaks decrease, and the S peak even disappears once the etching time increase to 500 s. This hints that the rear surface of C7 was reached for the etching time between 375 and 500 s. In the following UPS depth profile analysis, the spectra of the C7 sample with etching for 375 s could reveal the band structure of C7 rear surface. The corresponding UPS cutoff spectra of C7 for different etching time  are shown in Figure 2S3‐CdS composites layer (C7) has a gradual CBM structure (4.28 eV for the surface and 3.81 eV for the rear surface). The CBM of rear surface of C7 layer is slightly higher than that of the Sb2Se3 absorber /ZnO/Al:doped ZnO. Figure Table 2Se3 solar cell exhibits an open‐circuit voltage (VOC) of 405 mV, a short‐circuit current density (JSC) of 28.70 mA cm−2, a fill factor (FF) of 63.60%, and a power conversion efficiency (PCE) of 7.39%. Meanwhile, the typical In2S3 single buffer‐based cell shows a PCE of 3.41% from the declining VOC, JSC, and FF. Notably, it is clear that all devices with In2S3‐CdS composite buffers  demonstrate remarkable enhancement in VOC, JSC, and also PCE than the devices with CdS or In2S3 single buffer. The highest PCE of 9.19% is achieved for device with C7 buffer with VOC of 461 mV, JSC of 29.92 mA cm−2, and FF of 66.67%. It is worth noting that VOC was promoted from 405 to 461 mV after the application and optimization of In2S3‐CdS composite buffers, which will be discussed later. On the other hand, the JSC of solar cells with composite buffers exhibit slightly higher values than the device with CdS single buffer, and much higher than the device with single In2S3 buffer.To clarify the relationship between the different types of buffer layers and the photovoltaic properties of the Sb2S3 single buffer has a better photospectral response in this short‐wavelength range. This could be attributed to its thinner thickness than the In2S3‐CdS buffers and bigger bandgap than the CdS layer, which allow more photons pass through and be absorbed by the Sb2Se3. This could be ascribed to the narrow bandgap of CdS (2.39 eV) thin films, and the photons was absorbed by the CdS buffer before it arrived the Sb2Se3 layer without contribution much to the photocurrent due to its high doping density. In the medium wavelength range (500–750 nm), the EQE was determined the Sb2Se3 absorber and absorber/buffer heterojunction interface quality. In comparison with CdS/Sb2Se3 interface, the coverage for In2S3 nanosheet on the Sb2Se3 rod surface is poor. The exposed Sb2Se3 surface is covered by the following CdS, and the coverage is improved after the formation of In2S3‐CdS composite buffers. Hence, devices with composite buffers  exhibit higher values than the reference CdS device, suggesting the variation in the heterojunction. In the longer wavelength range (750–1000 nm), the EQE values for devices with composite buffers show slight decrease. It could be ascribed to the incomplete collection of photogenerated carriers in the absorber, and the biased EQE measurement at −0.5 V  of champion cells from each group are displayed in Figure JSC‐decay and VOC‐decay were conducted to explore the photogenerated carrier dynamics in the solar cells. The charge transport lifetime (tτ) could be derived from the JSC‐decay curves, while the VOC‐decay curves are corrected to the carrier recombination rates under the open‐circuit conditions in the full solar cells. Figure VOC‐decay curves of the Sb2Se3 nanorod solar cells with various buffers. The curves for the composite buffer‐based solar cells exhibit much slower decays, in comparison with the reference CdS buffer‐based device. The charge recombination lifetime (rτ) derived from the VOC‐decay curves was calculated to be 6.79 and 1.63 ms for C7 and CdS device, respectively. This suggested that the carrier recombination was dramatically prohibited by involving the In2S3‐CdS composite buffer in the device.J–V–T) measurement was further carried out to investigate the mechanism of carrier transport at the heterojunction interface, as shown in Figure VOC versus temperature plot, and the relationship can be described by the following equationTemperature‐dependent current density voltage  absorber layer. On the other hand, all the devices with double buffers exhibit higher Ea values  than the cell with single CdS buffer. This behavior of Ea could be interpreted from the perspective of band structure of the heterojunction interface. The CBM of CdS is lower than that of Sb2Se3 absorber in the CdS/Sb2Se3 heterojunction, which enhances the possible interface recombination due to cross‐recombination. In this case, the activation energy Ea is smaller than the bandgap of Sb2Se3 absorber, and may be close to the energy difference between the CBM of CdS and the VBM of Sb2Se3. This results in a lower VOC. The negative CBO (cliff‐like) became positive (spike‐like) after the introduction of In2S3‐CdS composite buffers, and the cross‐recombination paths are reduced and the interface recombination rate decreases, which would lead to an increase in Ea and be more beneficial to achieve higher VOC. Moreover, If the CBO becomes too large, the photogenerated electrons transferring from the Sb2Se3 absorber toward the top TCO contact are blocked by the high electron barrier at the junction interface, resulting in a decrease in photoresponse.Where 32S3 nanoflake/CdS composite layer is an efficient buffer layer for the Sb2Se3 nanorod array solar cells. Morphological and structural analyses revealed that In2S3‐CdS composite shell compactly covers the surface of Sb2Se3 nanorod. The best‐performing device based on In2S3‐CdS composite buffers achieved a PCE of 9.19% (VOC 461 mV), compared to that of the single In2S3 nanoflake buffer‐based device of 3.41% (302 mV) and single CdS buffer‐based device of 7.39% (405 mV). The gradient band structure, high‐transmittance at short wavelengths, and low recombination of photogenerated carriers at the Sb2Se3/buffer nanorod array junction interfaces are responsible for the enhanced efficiency.In conclusion, a low‐temperature solution‐processable In42S3 nanoflake film was grown using thioacetamide  and indium chloride  as S and In precursors, respectively. In a typical procedure, 1.26 g citric acid  and 0.45 g C2H5NS were added into 60 mL of 25 × 10−3 m InCl3 solution with stirring. Then, the precursor solution was transferred to Teflon‐lined autoclave and the prepared Mo/MoSe2/Sb2Se3 substrate was immersed in the reaction solution. The autoclave was put into a preheated box furnace and kept at 80 °C for 100 min. After the reaction, the samples were washed with deionized (DI) water and ethanol and dried at 100 °C in the air for 30 min. Finally, the CdS layer was prepared by a typical CBD method. Add 15 × 10−3 m of cadmium sulfate  and 37 × 10−3 m of thiourea  and 58.9 mL of ammonia (28%) to 585 mL of deionized water, stirring in a water bath (70 °C) for different time , and the samples were washed with DI water and dried with clean dry air.The In2Se3 nanorod array solar cells were fabricated in a substrate configuration (glass/Mo/MoSe2/Sb2Se3/buffer layer/i‐ZnO/AZO), as described in our previous work. The Mo back contact layer was prepared by 1200 W DC sputtering under a 0.3 Pa argon, in which the obtained Mo thickness was about 800 nm. Then, the as deposited W layer was transferred into a vacuum chamber for selenization. During the selenization, the vacuum chamber pressure was pumped down to 10−4 Pa and the substrate temperature was kept at 620 °C for 30 min. Approximately 1 µm thick Sb2Se3 nanorod array absorber layers were deposited by close space sublimation by a process of our previous recipe: the deposition started when the pressure was below 10−2 Pa. First, the source and sample holder were warmed up to 480 and 270 °C, respectively, in 200 s, and maintained at the high temperatures for 100 s to obtain the Sb2Se3 absorbers with thickness of 1 µm. Different buffers  were prepared by the above process. Window layers of i‐ZnO and AZO were deposited by RF magnetron sputtering to a thickness of 70 and 300 nm, respectively.Sb+ ion source with energy of 2 KeV was used, the reference etching rate was 0.60 nm s−1 for Ta2O5. The optical properties of the thin film were measured using a spectrophotometer equipped with an integrating sphere (Perkin‐Elmer Lambda 950). To characterize the device performance, J‐V measurements were performed on the devices using an AM1.5 solar simulator equipped with a 300 W xenon lamp . The external quantum efficiency (EQE) was measured using an Enlitech QER3011 system (Enlitech) equipped with a 150 W xenon light source. The photocurrent decay under short circuit and photovoltage decay under open‐circuit conditions were measured by an electrochemical workstation .The morphology of the films was observed by high resolution field emission SEM (FEI nova nano SEM450) and atomic force microscopy (Veeco Multimode 8). XPS and UPS measurements were carried out using an X‐ray photoelectron spectrometer and an ultraviolet photoemission spectrometer , respectively. For the In‐depth XPS and UPS measurement, an ArThe authors declare no conflict of interest.Supporting InformationClick here for additional data file.


Phytophthora sojae. This method relies on effector‐triggered immunity, where a Resistant to P. sojae (Rps) gene product from the plant recognizes a specific effector from the pathogen, encoded by an avirulence (Avr) gene. Many Avr genes from P. sojae have been identified in the last decade, allowing a better exploitation of this type of resistance. The objective of the present study was to identify the Avr gene triggering immunity derived from the soybean resistance gene Rps8. The analysis of a segregating F2 progeny coupled with a genotyping‐by‐sequencing approach led to the identification of a putative Avr8 locus. The investigation of this locus using whole‐genome sequencing data from 31 isolates of P. sojae identified Avr3a as the likely candidate for Avr8. Long‐read sequencing also revealed that P. sojae isolates can carry up to five copies of the Avr3a gene, compared to the four previously reported. Haplotype and transcriptional analyses showed that amino acid changes and absence of Avr3a transcripts from P. sojae isolates caused changes in virulence towards Rps8. Functional analyses using CRISPR/Cas9 knockout and constitutive expression demonstrated that Rps8 interacted with Avr3a. We also showed that a specific allele of Avr3a is recognized by Rps3a but not Rps8. While Rps3a and Rps8 have been previously described as closely linked, this is the first report of a clear distinction hitherto undefined between these two resistance genes.The use of resistance genes in elite soybean cultivars is one of the most widely used methods to manage  Avr3a from Phytophthora sojae (causing Phytophthora root rot) triggers immunity derived from the soybean resistance gene Rps8.The RXLR effector coded by a specific allele of the avirulence gene  In poorly drained fields with a history of the disease, yield losses can reach 100% when susceptible cultivars are planted   and EER (Glu‐Glu‐Arg) motifs produced by avirulence (Avr) genes in the pathogen. The recognition of these avirulence factors will lead to effector‐triggered immunity in the host plant  approach. By taking advantage of exhaustive whole‐genome sequencing (WGS) data for a collection of P. sojae from a previous study  and 7B (virulent on Rps8), three F1 hybrids were obtained, and the phenotypic assay revealed that they were all avirulent on Rps8  for an average of 1.34 million reads per isolate were obtained, and 97.7% of these reads were successfully mapped to the P. sojae reference genome (v. 3.0). After retaining positions with a coverage depth equal to or higher than 10, these reads covered approximately 2.5% of the whole genome and 29,053 single‐nucleotide polymorphisms (SNPs) were successfully called from these data . Using SnpEff, it was found that 35% of those SNPs were in coding regions and 51% in the immediate vicinity of a coding region (1000 bp upstream or downstream of a coding region), with the remaining 14% located in intergenic regions. Among SNPs present in the coding regions, 63% induced nonsynonymous mutations. After filtering and imputation of missing data, a set of 1613 SNPs was retained  pool and an avirulent (A) pool. For each SNP, the frequency of each allele was estimated in the entire F2 population, as well as in pools V and A. For each SNP in each pool, χ2 tests were performed to assess segregation distortion from the entire F2 population. When a SNP locus presented a significant segregation bias in both pools and the genotype of the favoured allele matched the parent with the corresponding phenotype, it was considered as potentially linked to Avr8. In pool V, a total of 60 SNPs inherited from the virulent parent presented a segregation bias while 21 SNPs in pool A, inherited from the avirulent parent, had a significant segregation distortion. From these selected SNPs, three consecutive SNPs were present in both pools and exhibited p values and genotype distributions that met all expected criteria for an avirulence locus. The allele frequencies of the candidate alleles for each SNP in each pool are presented in Table 2 isolate for each of these variants is shown in Figure Two pools of individuals were created based on their phenotypic reaction on Avr genes (Avr3a‐1 and Avr3a‐2) or effectors based on the presence of RXLR motifs .The region circumscribed by the candidate SNPs is a gene‐rich region with a total of 34 genes, from which five have been previously characterized as either 2.2P. sojae, including parents 7B and 45C, variants located in the Avr8 locus and for which the virulent parental isolate 7B carried the alternative allele were extracted. A total of 252 SNPs and indels smaller than 50 bp, two deletions of more than 50 bp, and one copy number variation were found in this region  and two copies of the Avr3a gene . Five variants out of these 60 were also predicted to have a potentially high impact on the proteins coded by five different genes, including Avh37 (frameshift insertion) and Avr3a‐1 and Avr3a‐2 (loss of stop codon for both genes). Furthermore, the copy number variation region detected in the parents included both copies of Avr3a‐1 and Avr3a‐2 represented in the reference genome of P. sojae, which are two exact copies of the same gene. The two deletions of 276 bp detected in the virulent parent were also located 1.1 kb upstream of Avr3a‐1 and Avr3a‐2. A summary of the impact of the variants on RXLR effector genes at the Avr8 locus is presented in Figure Avr8 locus are shown in Table Avh37 and Avr3a as the most promising candidates for Avr8.Using SnpEff, it was revealed that 75% of these variants were nonsynonymous and could potentially affect 28 out of 34 genes  motif of the protein and leading to a truncated protein before the predicted effector domain containing the W‐like motif near the C‐terminal end  are shown in Figure Rps8. By contrast, inoculation with the Avr3a45C knockout isolate led to a phenotype of virulence on plants carrying Rps8. As shown in Figure Rps8 showed resistance in both the aerial and root parts when inoculated with the WT isolate 45C, compared to the susceptible control plants Haro (1‐7)1. For their part, plants containing Rps8 showed a compatible reaction when inoculated with the Avr3a45C knockout isolate, thus indicating that the lack of Avr3a45C gene resulted in a gain of virulence in the presence of Rps8.The stable transformant obtained from CRISPR/Cas9 transformation targeting the Avr3a45C, transcript analysis confirmed its expression in transformed isolates 7C OE‐Avr3a‐1, ‐2, and ‐3, while it went undetected in WT isolate 7B 1, as anticipated. In contrast, transformed isolates expressing Avr3a45C were avirulent on plants containing Rps8, demonstrating that constitutive expression of Avr3a45C in P. sojae isolate 7B causes gain of avirulence in the presence of Rps8.With respect to the constitutive expression of B Figure . PhenotyAvh37, transcript analysis was performed on WT isolate 7B (virulent in the presence of Rps8) and the three stable transformants obtained  from constitutive expression of Avh3745C. This analysis showed expression of the gene in transformed isolates and none in the WT isolate 7B 1. Similar virulent responses were observed on plants inoculated with the transformants, showing that overexpression of Avh37 did not cause an incompatible interaction with plants containing Rps8.For candidate gene B Figure . Phenoty2.5Avr3a locus, Nanopore long‐read sequencing was performed for parental isolates 45C and 7B. To observe the inheritance pattern of the Avr3a region in the progeny, two F2 isolates  were also sequenced. From the parental isolate 45C, a read was obtained with a length of 79,521 kb that carried five identical copies of the Avr3a gene. Each copy was embedded in a segment of 10.8 kb with four other genes, and this segment was repeated five times, as a result of tandem duplication . This alignment showed that five identical copies of the Avr3a gene were also present in the avirulent F2 progeny. To define the Avr3a region in parental and F2 isolates virulent on Rps8 (7B and 8‐3‐34), de novo assembly and alignment of contigs on the 45C new consensus sequences were performed, which demonstrated a clear deletion of four copies of the 10.8‐kb repetitive unit in both strains  also support that these five copies are inherited by the F2 progeny. The fifth copy of the Avr3a gene defines a new haplotype for this Avr gene and emphasizes the role of this effector in pathogenicity, prior to its recognition by different resistance genes.The Avr8 were as virulent against Rps8 as they were against Rps3a. Furthermore, 34 of the 35 isolates phenotyped in this study gave a similar response when tested against Rps8 and Rps3a , a change that could possibly explain the differential responses of Rps3a and Rps8 towards its gene product  15, 17, 24, or 26. All four were highly virulent on soybeans carrying Rps8  and PI399073a (Rps8) and a susceptible control cultivar not carrying the appropriate Rps gene were tested. Phenotypic responses for resistance or susceptibility were recorded at 10 days postinoculation (dpi) and based on comparative responses of control resistant and susceptible cultivars.Detailed information about the 35 4.2Rps8, two P. sojae isolates from our collection, 45C (avirulent on Rps8) and 7B (virulent on Rps8), were crossed to obtain F1 and F2 progenies. Pieces of mycelium from long‐term storage were transferred on 20% V8 gellan gum (0.4%). The Petri dishes were placed in an incubator at 28°C. After 1 week of growth, mycelia from the two isolates were mixed together with a syringe and transferred on Petri plates containing crossing medium . The plates were left in the dark at room temperature. After 3 weeks, two plates were sliced using a sterile blade and blended together in a prechilled blender for 2 min with 50 ml of fridge‐cold sterile water. The mix was filtrated through four layers of sterile cheesecloth to remove agar and mycelium and the filtrate was transferred to a 50‐ml sterile conical tube. The mixture was kept on ice for 24 h to kill the residual mycelium. The filtrate was then centrifuged at 956 × g  for 3 min and the supernatant was removed. The pellet of oospores was washed three times with sterile water and centrifugation cycles. Oospores were transferred on water agar supplemented with penicillin at a concentration of 500 oospores per Petri dish and spread with a sterile loop. After three or four days, each germinating oospore was transferred individually using a 20‐gauge needle and grown on 20% V8 agar medium for subsequent DNA extraction.To follow the inheritance of virulence towards 4.31 hybrid progeny from crosses of 45C × 7B, codominant DNA markers polymorphic between the parents were used to determine whether the individuals resulted from self‐fertilization or from outcrossing events between the parental isolates (F1). The polymorphism used to distinguish alleles from both parents was a deletion; isolate 7B has a deletion of 35 bp in the amplicon region while isolate 45C does not. Selected F1 hybrid isolates were then cultured individually on crossing medium in the dark at room temperature for self‐fertilization and generation of F2 individuals. Oospores produced from F1 individuals were isolated using the method described above and grown on 20% (vol/vol) V8 agar medium. All F1 and F2 individuals were phenotyped for their compatibility interaction with Rps8 using the hydroponic assay developed by Lebreton et al. (Rps8) and susceptible control Haro (1‐7)1 (rps).DNA of each culture grown from pure isolated oospores was extracted using an adapted cetyltrimethylammonium bromide (CTAB) and chloroform/isoamyl alcohol extraction method followed by isopropanol precipitation. To determine Fn et al.  and cult4.4Rps8 and to identify potential candidate genes for Avr8, the F2 progenies were genotyped using a GBS approach. DNA from F2 individuals was extracted using the CTAB and chloroform/isoamyl alcohol method followed by isopropanol precipitation. DNA was quantified using a Qubit 4 fluorometer (Thermo Fisher Scientific) and concentrations were normalized to 10 ng/µl for library preparation. Sequencing libraries were prepared using the ApeK1 restriction enzyme following the protocol from Elshire et al.  solely and we know that the isolate used to produce the reference genome (P6497) is avirulent on Rps8, we only kept variants from which the virulent parent isolate 7B (avr8) carried the alternative allele and the parent isolate 45C (Avr8) carried the reference allele.To find potential candidate genes in the region of 7.13 Li, . Calling7.13 Li, . Larger 7.13 Li,  and Mant7.13 Li, . Finally7.13 Li, . Because4.6P. sojae‐infected soybean roots using TRIzol reagent followed by purification using the RNeasy Mini kit (Qiagen). RNA samples were treated with DNase I enzyme to avoid DNA contamination and 2 µg of each sample was used for the conversion to single‐stranded cDNA using random primers and the multiscribe reverse transcriptase from the High‐Capacity cDNA Reverse Transcription Kit (ThermoFisher Scientific). Primers for the reverse transcription PCR were designed using the PrimerQuest tool.RNA isolation was performed on 7‐day‐old 4.7Avr3a45C knockouts using CRISPR/Cas9, single‐guide RNAs (sgRNAs) were designed using EuPaGDT . The gBlock was assembled in NheI‐ and BsaI‐digested plasmid pYF515  were assembled in pRB‐Avr6 digested with KpnI and AvrII using HiFi NEB assembly (New England Biolabs). Plasmids were sequence‐verified and named pRB‐OE‐Avr3a and pRB‐OE‐Avh37.For constitutive expression of 4.8P. sojae avirulent isolate 45C and virulent isolate 7B, respectively, using polyethylene glycol‐mediated transformation following a previously published protocol  and constitutive expression vectors (pRB‐OE‐Avr3a and pRB‐OE‐Avh37). Transformants growing on regenerative medium containing 50 μg of G418 (Thermo Fisher Scientific) were selected and subcultured on V8 gellan gum medium supplemented with G418. To detect the presence of indels in Avr3a, genomic DNA was isolated from the stable transformants and the entire open reading frame of Avr3a was amplified and sequenced. For the constitutive expression of the Avr3a45C gene, primers M13R and M13F were used to amplify the expression cassette (promoter‐gene‐terminator) from the transformants' genomic DNA.Knockout and constitutive expression vectors were introduced in 4.9P. sojae transformants towards Rps8 was evaluated with the hydroponic system described previously  and Williams L83‐570 (Rps3a) and the susceptible control Haro (1‐7)1 (rps). The virulence phenotype towards Rps3a was also evaluated using Williams L83‐570 (Rps3a) and the susceptible control Williams (rps rps). Plants were scored based on a 1 to 5 scale developed by Lebreton et al. (rps), the isolate was considered virulent, and when values were statistically lower, the isolate was considered avirulent.The virulence profile (phenotype) of selected n et al. , where 14.10P. sojae isolates grown in liquid culture for 7 days with an adapted CTAB and chloroform/isoamyl alcohol method that uses a lower incubation temperature and reduced centrifugation speed to avoid DNA shearing. DNA purity was assessed with a NanoDrop spectrophotometer and quantification was performed with a Qubit 4 fluorometer. DNA libraries were prepared according to the protocol of Oxford Nanopore Technologies using the adaptor ligation kit (SQK‐LSK109). Sequencing was performed on a SpotON R9.4 flow cell using a MinION device. Sequences were base‐called with Guppy v. 3.2.4. Adapters were trimmed with Porechop (https://github.com/rrwick/Porechop) and reads were filtered for quality (Q > 7) with NanoFilt  Nucleotide sequence alignment. (b) Protein sequence alignmentClick here for additional data file.FIGURE S3 Susceptibility scores of soybean plantlets inoculated with Phytophthora sojae wild‐type strain and transformed isolates complementing the phenotyping assay in Figures 4–6. (a) Knockout of Avr3a45C in isolate 45C . (b) Overexpression of Avr3a45C in isolate 7B . (c) Overexpression of Avh3745C in isolate 7B . Interactions were considered incompatible when values (indicated with a *) were significatively different from the susceptible control rps (Haro (1‐7)1) according to Dunnett’s test (p < 0.01)Click here for additional data file.FIGURE S4 Reverse transcription PCR to detect Avh3745C and Avr3a45C transcript presence in wild‐type strain 7C and transformed strains using constitutive expression with the Ham34 promoterClick here for additional data file.FIGURE S5 Alignment of the predicted amino acid sequences of the three different alleles of Phytophthora sojae Avr3a used in this study. Signal peptide, RXLR and EER motifs are shown and polymorphic residues among the different alleles are highlighted with a red background. Asterisk represent amino acid changes in Avr3aACR12, compared to Avr3a45C, that leads to a recognition of the gene product by Rps3a, but not Rps8 in soybean plantsClick here for additional data file.FILE S1 Consensus sequence of the Avr3a region from Phytophthora sojae isolate 45CClick here for additional data file.TABLE S1 List of all variants found in the Avr8 locus of Phytophthora sojae and carried by isolate 7B (virulent parent used for generation of the F2 population)Click here for additional data file.TABLE S2 List of Phytophthora sojae isolates used in this study.Click here for additional data file.TABLE S3 Metrics for Nanopore long‐read sequencing of Phytophthora sojae isolatesClick here for additional data file.


The PRMT5–MEP50 methyltransferase complex plays a key role in various cancers and is regulated by different protein–protein interactions. Several proteins have been reported to act as adaptor proteins that recruit substrate proteins to the active site of PRMT5 for the methylation of arginine residues. To define the interaction between these adaptor proteins and PRMT5, we employed peptide truncation and mutation studies and prepared truncated protein constructs. We report the characterisation of the interface between the TIM barrel of PRMT5 and the adaptor proteins pICln, RioK1 and COPR5, and identify the consensus amino acid sequence GQF[D/E]DA[E/D] involved in binding. Protein crystallography revealed that the RioK1 derived peptide interacts with a novel PPI site. Determination of a PPI interface: The adaptor protein binding site of PRMT5 has been identified and studied by using synthetic peptides. A cocrystal structure of the PRMT5 TIM‐barrel domain and a RioK1‐derived peptide highlights the site of interaction. Methylation of terminal arginine nitrogens by protein arginine methyltransferases (PRMTs) plays important roles in various cellular processes, including the establishment of cancer.PRMT5 contains three domains, that is, the catalytic site‐containing Rossmann fold, a β‐barrel domain used for dimerization, and the TIM barrel, which acts as interaction site for MEP50 Figure A.3a, 3a, 3cHerein, we describe the use of synthetic peptides to study the PRMT5–adaptor protein interaction by biochemical methods and protein crystallography. An adaptor protein consensus sequence was derived by sequence alignment and synthetic peptides derived from this consensus were prepared. The site of interaction was initially determined by truncations of PRMT5 itself and measuring the affinity for synthetic adaptor protein peptides. Truncation and alanine scanning of the adaptor protein peptides allowed identification of the residues contributing to the interaction. A co‐crystal structure of a RioK1 derived peptide with the PRMT5 TIM barrel domain confirmed the results of our mutation and truncation studies. Our findings are in agreement with the recent preliminary report by Sellers et al.Homo sapiens protein data, resulting in the identification of two new sequence matches: COPR5  and DAB1 , 2 (KD 1.14 μM) and 3 (KD 0.55 μM), but not 4 , corresponding to the TIM barrel domain, was either expressed alone or co‐expressed as a complex with MEP50  led to a significant loss of affinity. To explore N‐terminal truncation, C‐terminally labelled 7 was synthesised which bound with a similar affinity as peptide 1. Truncating the N‐terminus showed that loss of the first three residues improved the binding (compound 8) but any further truncation led to a substantial loss of affinity (compounds 9 and 10). Compound 8, with the nine amino acid sequence VPGQFDDAD, constituted the smallest but still efficiently binding peptide fragment allowing for the interaction with PRMT5 (KD=208 nM). Extensions of either the N‐ or C‐termini led to improvements over peptide 1 but not in comparison to 8. Peptides derived from pICln showed similar trends where deletion of the negatively charged C‐terminal section resulted in loss of binding (compare compound 14 to 2) while extension led to an increase (compare 15 to 2). In contrast to the RioK1 derived peptides extension on the N‐terminus of the pICln peptide resulted in a twofold decrease in affinity (compare 16 to 2).In order to further define the requirements for pICln/RioK1/COPR5‐PRMT5 binding, we synthesised a series of RioK1 and pICln derived peptides Table  to deter17–22) and tested for binding to the TIM–MEP50 complex. No binding was observed in the performed FP assay  were able to compete with the fluorescently labelled 11, indicating that all peptides share the same binding site . The side chains of Val12 and Asp18 also contributed to the interaction (compounds 34 and 28), and substitution of Ala for Gly14 resulted in loss of affinity indicating that Gly is important for the correct conformation of the peptide (peptide 32). Mutation of the residues in the SRV and AD region, had either no, or a moderately positive impact on the interaction with the protein .To identify hot spot residues which provide the main contribution to the interaction,26 Table  which re23, using data to a resolution of 2.55 Å (PDB ID: 7BOC).More insight into the structural basis of the identified PRMT5‐pICln/RioK1/COPR5 interface was obtained from a co‐crystal structure of the TIM barrel domain in complex with peptide PPI web‐service, where a virtual alanine scan with a measurement of the change in the binding free energy (ΔΔG) of the protein–protein complex (PDB ID: 4GQB) was performed (Table S6).G values , and thus, high contribution to the PPI, were present in the disordered protein fragments , supporting the observation of the MEP50 stabilisation effect on the TIM barrel.The protein structure shows an unusual seven‐stranded β‐sheet with one antiparallel strand for the TIM barrel which is not observed in other PRMT5–MEP50 complexes.3a, 3c27, Table 9, Table The peptide is wedged into a shallow groove of the TIM barrel, formed between Lys240/241, Lys248 and Tyr286  should be addressed to the authors.SupplementaryClick here for additional data file.


However, they can also show Lewis acidity (LA) via Ge−CNHC σ* orbital. Utilizing this unique electronic feature, we report the first example of bis‐NHC‐stabilized germyliumylidene [MesTerGe(NHC)2]Cl (1), 2C6H3; NHC= IMe4=1,3,4,5‐tetramethylimidazol‐2‐ylidene) catalyzed reduction of CO2 with amines and arylsilane, which proceeds via its Lewis basic nature. In contrast, the Lewis acid nature of 1 is utilized in the catalyzed hydroboration and cyanosilylation of carbonyls, thus highlighting the versatile ambiphilic nature of bis‐NHC stabilized germyliumylidenes.Bis‐NHC stabilized germyliumylidenes [RGe(NHC) The versatile ambiphilic catalytic application of a bis‐NHC‐stabilized germyliumylidene enables a range of reductive functionalization reactions, with a particular emphasis on C=O reduction that is, CO2 and carbonyls. Based s Scheme b, Type BB classification, bis‐NHC stabilized germyliumylidenes are comparatively Lewis basic and relatively more stable than type A germyliumylidenes, due to the occupied p‐orbitals. Thus, on one hand they can be used as a robust Lewis base catalyst whilst on the other hand they can be used as a Lewis acid catalyst, due to the ability of the Ge−CNHC σ* orbitals to accept electrons, which provides an additional cooperative site for potential catalytic application. Despite these unique electronic features, the catalytic application of germyliumylidenes is in its infancy. Recent examples from the groups of Rivard and Nagendran have shown the role of type A and B germyliumylidenes, respectively, in the hydroboration of carbonyls.Among the type 2 with a germa‐acylium ion (NHC)2]Cl) 2C6H3; NHC=IMe4=1,3,4,5‐tetramethylimidazol‐2‐ylidene) which proceeds through the active germylene species (NHC)).2 via the formation of a hypercoordinate silane intermediate. Moreover, it has been shown that the Lewis acidity and Lewis basicity are both important for the catalytic transformation of CO2[MesTerGe(NHC)2]Cl (1) towards a range of catalytic reductive functionalization reactions, with a particular emphasis on C=O reduction i. e., CO2 and carbonyls.Very recently, we have reported hydrosilylation of COon of CO22h, 8 1 was found to transform CO2 into the corresponding hydrosilylated products in both a stoichiometric and catalytic manner in the presence of phenylsilane (PhSiH3). The 1H NMR spectrum revealed the complete consumption of PhSiH3 within 2.5 h at 60 °C, with the formation of silylformate, bis(silyl)acetal and silylated methanol observed . As expected, use of more sterically protected silanes required increased reaction times (PhSiH3 2.5 h vs. Ph2SiH2 3.5 h), and in the case of Ph3SiH, higher temperatures and prolonged reaction times are required (28 h at 80 °C). Furthermore, solvent optimization studies found increased rates of reaction in polar solvents  compared to non‐polar solvents . This, however, can also be attributed to the low solubility of the catalyst in non‐polar solvents. To consider the influence of the counter ion in catalysis, the reaction was performed using the anion‐exchanged 1[BArF], [BArF={2C6H5)4B], catalyst in CD3CN, no significant change in the rate of reaction was found. This points towards the dependence on the cationic germanium center during the catalysis. With the above points considered, use of 5 mol % of 1 with PhSiH3 in CD3CN at 60 °C provides the optimal reaction conditions for this study.Following a similar protocol to the previous NHC‐stabilized germa‐acylium catalysis,1 is lower in comparison to our previously reported germa‐acylium ion catalyst (TOF: I=13.2 h−1 vs. 1=7.9 h−1 for PhSiH3 at 60 °C),1 has the added advantage of being a more stable catalyst as well as requiring fewer synthetic steps. Using the optimized conditions mentioned above, the longevity of catalyst 1 was examined in which additional PhSiH3 and 1 bar of CO2 were added to the J‐Young NMR tube at the end of the cycle. This process could be repeated four times before a small drop in turnover was observed (TOF: Run 1=8 h−1 vs. Run 4=6 h−1). In contrast, the previously reported germa‐acylium ion catalyst decomposed after the third cycle.Whilst the catalytic activity of 1 and CO2 in the absence of silane, even after prolonged heating at 60 °C. Additionally, no reaction was observed with varying equivalents of hydrosilane under the optimal catalytic conditions. This suggests a cooperative silane/CO2 mechanism, and therefore, the mechanism was investigated computationally . In a similar fashion to the previous case,3 is activated by the germanium lone pair in +1M and the hydride transfer from the hypercoordinate silane to the free CO2 occurs in a concerted process via the transition state TS‐1  following a three‐component mechanism. Additionally, participation of the germanium lone pair in “concerted SN2@Si‐acceptor” mechanismTS‐1. This step needs to surmount an energy barrier of 28.6 kcal mol−1 to provide the resulting intermediate (INT‐1). The Lewis basicity of NHC‐stabilized germyliumylidene towards PhSiH3 cannot be explained by drastically high energy separation (11.0 eV) between the germanium lone pair orbital in free +1M and Si−H σ* orbital in free PhSiH3 . However, when the silane approaches the Ge center, significant stabilization of the Si−H σ* orbital in the PhSiH3 fragment of TS‐1 results in favorable interaction (8.3 eV) with the germanium lone pair in the +1M fragment, thus enhancing the reactivity of germyliumylidene and highlighting the Lewis basic nature of +1M . In the alternative pathway, oxidative addition of silane across the Ge center in +1M with concomitant liberation of IMe4 demands slightly lesser energy barrier of 28.2 kcal mol−1 , as suggested by favorable interaction (8.2 eV) between the Si−H σ and Ge−CIMe4 σ* orbitals in TS‐7 . However, CO2 insertion into the Ge(IV) hydride species (INT‐5) in the subsequent step demands drastically high intrinsic activation barrier of 44.9 kcal mol−1 and can be safely discarded. Moreover, +1M does not coordinate with either CO2 or silane. Thus 1[Cl] assisted hydrosilylation of CO2 is proposed to occur through three‐component pathway rather than a two component mechanism. In agreement with experimental findings, the computed activation barriers for TS‐1 increase with decreasing number of hydrides on the silane . INT‐1 finally delivers the formoxysilane (P) accompanying an energy barrier of 3.8 kcal mol−1.A series of stoichiometric reactions were undertaken to probe the mechanism. No reaction was observed with − (formamide), 4e−  and 6e‐(methylamine) reduced products within 2 h, whereas N‐methylaniline (Table I) lower activity was again observed for reductive N‐functionalization catalysis. This may, in part, be due to the role of the Ge center in the subsequent conversion of the formoxysilane product to the functionalized amine. In this system no metal center is implicated in the computed mechanism and formation of PhSiH2OH requires a slightly higher energy barrier for the reduction of formamide compared to the former germa‐acylium ion system.Further comparisons to the previous germa‐acylium ion catalysis were sought through the extension to reductive N‐functionalization of amines.ne Table , Entry 51, whilst not as active as the germa‐acylium system,2C(OTMS)CN] serves as a synthon for numerous biologically relevant molecules such as α‐hydroxyacids, α‐amino acids, and β‐amino alcohols.Germyliumylidiene catalyst 1, proceeds under mild conditions compared to the previously reported germylenes and transition metal catalysts.[−1 and aromatic aldehyde TOF=900 h−1). For benzophenone, increased catalyst loadings (1 mol %) and higher temperatures (50 °C) are required, likely due to the increased steric protection around the carbonyl moiety.Catalytic cyanosilylation of aldehydes and ketones, mediated by atalysts.2g, 133SiCN to the Ge center via TS‐14 followed by de‐coordination of IMe4, leads to the formation of INT‐10  with concomitant elongation of the Ge−CIMe4 bonds (2.372/2.313 Å) compared to those in +1M (2.076/2.066 Å). The significant weakening of the CIMe4→Ge interactions in TS‐14 is also reflected in the Wiberg bond indices calculated for these bonds . NOCV calculations reveal that the strongest orbital interaction in TS‐14 originates from the σ‐donation of nitrogen lone pair in Me3SiCN to the Ge−CIMe4 σ* orbitals in +1M . Analogous to the previous hydrosilylation mechanism, the electrophilic nature of +1M cannot be explained by the orbital interactions between free +1M and Me3SiCN species . The promotion of the +1M fragment from its ground state equilibrium geometry to the perturbed form in TS‐14, as Me3SiCN approaches the Ge center, results in lowering of the Ge−CIMe4 σ* orbital from the LUMO+10 in the free +1M to LUMO in the +1M fragment of TS‐14 .IMe4 σ* orbital in TS‐14 allows the germyliumylidene to exhibit its Lewis acidic nature towards Me3SiCN. The incoming carbonyl essentially inserts into the C−Si bond of NCSiMe3 via a 4‐membered cyclic transition state (TS‐15). This step needs to overcome overall energy barrier of 33.6 kcal mol−1 to furnish the substantially more stable intermediate (INT‐12). Similar moderately high activation barrier for cyanosilylation reactions at room temperature have been reported earlier.[4 and a product de‐coordination step to deliver the desired cyanohydrin product accompanies an energy barrier of 7.5 kcal mol−1 In the alternative pathway, the substitution of IMe4 in +1M by RCHO demands slightly lower energy barrier of 28.6 kcal mol−1 compared to that by Me3SiCN . However, the Si−CN bond activation in the incoming Me3SiCN by free NHC in the subsequent step needs to surmount a significantly higher energy barrier of 37.1 kcal mol−1 and hence, the initial coordination of RCHO to the Ge center in +1M via ligand exchange can be safely discarded. Moreover, theoretical endeavor to optimize the transition state similar to TS‐1 . However, geometry optimization of such hypercoordinate silane adduct (INT‐37) remained unsuccessful at the R‐BP86/def2‐SVP level. Importantly, we were able to optimize INT‐37 at the R‐M06‐2X‐D3/def2‐TZVP level. Our calculations suggest that the formation of INT‐37 is extremely endergonic by 29.5 kcal mol−1 and its generation also demands an activation barrier of 30.8 kcal mol−1 . The subsequent −CN transfer to the carbonyl carbon in the incoming substrate demands an energy barrier of 32.9 kcal mol−1. Importantly, the favorable pathway for the cyanosilylation reaction  shows the rate‐limiting energy barrier of 31.8 kcal mol−1 at the same level of theory. Moreover, structural optimization of the intermediate generated by the nucleophilic attack of +1M to the RCHO failed despite several attempts . Hence, the Lewis basicity of the germyliumylidene for the cyanosilylation reaction is less likely to operate on kinetic ground.DFT studies indicate that initial coordination of Me2E:, E=Si−Sn)[1 towards various aldehydes with pinacol borane (HBpin) as the hydroboration reagent. In line with previous studies, less bulky substituents 2b, 154 by RCHO via TS‐22 accompanying the rate‐limiting activation barrier of 29.2 kcal mol−1 . Similar to TS‐14, the unique bonding features of the +1M and RCHO fragments in TS‐22 can nicely explain electrophilic nature of germyliumylidene in hydroboration reactions. The significant stabilization of Ge−CIMe4 σ* orbital in the +1M fragment of TS‐22 compared to that in the free +1M facilitates the nucleophilic attack of aldehyde . The subsequent B−H bond activation in HBpin is mediated by the free IMe4.[INT‐21 transfers the hydride to the carbonyl carbon in INT‐20. This is followed by the coordination of boron to the oxygen center generating the substantially stable intermediate INT‐23. Finally, the IMe4 ligand transfer to the Ge center demands an energy barrier of 26.8 kcal mol−1 to afford the desired product and regenerate +1M. Notably, unlike transition metals,4 ligand plays a key role in this transformation, subsequent control experiments highlight the requirement for the Ge center .Similar to the cyanosilylation mechanism, the favorable pathway of hydroboration of aldehyde shows the initiation of the reaction by substitution of IMe1 Figure  and S64.1)‐catalyzed hydrosilylation of CO2 and N‐methylation of amines using CO2 as a C1 source, where 1 acts as a Lewis base towards silane due to the presence of a lone pair on the germanium atom. Additionally, exploiting the electronic features of 1 other organic transformations, such as cyanosilylation and hydroboration of carbonyls, have been achieved under mild conditions. This is possible due to the accessible Ge−CNHC σ* orbitals, which allow 1 to exhibit its electrophilic nature in cyanosilylation and hydroboration reactions. With the observed high catalytic activity and versatile transformations, this NHC‐stabilized germyliumylidene catalyst provides a viable alternative towards transition metal‐free catalysis.In conclusion, we have demonstrated for the first time the utilization of a well‐defined low valent group 14 tetryliumylidene complex for diverse organic transformations. This includes the germyliumylidene  should be addressed to the authors.Supporting InformationClick here for additional data file.