The Experts below are selected from a list of 2925 Experts worldwide ranked by ideXlab platform
Jinquan Wei - One of the best experts on this subject based on the ideXlab platform.
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elucidating the key role of a Lewis base solvent in the formation of perovskite films fabricated from the Lewis Adduct approach
ACS Applied Materials & Interfaces, 2017Co-Authors: Xiaobing Cao, Fei Fang, Youwei Yao, Lili Zhi, Xian Cui, Kongxian Ding, Jinquan WeiAbstract:High-quality perovskite films can be fabricated from Lewis acid–base Adducts through molecule exchange. Substantial work is needed to fully understand the formation mechanism of the perovskite films, which helps to further improve their quality. Here, we study the formation of CH3NH3PbI3 perovskite films by introducing some dimethylacetamide into the PbI2/N,N-dimethylformamide solution. We reveal that there are three key processes during the formation of perovskite films through the Lewis acid–base Adduct approach: molecule intercalation of solvent into the PbI2 lattice, molecule exchange between the solvent and CH3NH3I, and dissolution–recrystallization of the perovskite grains during annealing. The Lewis base solvents play multiple functions in the above processes. The properties of the solvent, including Lewis basicity and boiling point, play key roles in forming smooth perovskite films with large grains. We also provide some rules for choosing Lewis base additives to prepare high-quality perovskite fi...
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high quality perovskite films fabricated from Lewis acid base Adduct through molecular exchange
RSC Advances, 2016Co-Authors: Xiaobing Cao, Fei Fang, Xuemin Cui, Youwei Yao, Jinquan WeiAbstract:We describe a facile method to fabricate high quality CH3NH3PbI3 films with smooth surface and without residual PbI2 through molecular exchange, rather than ionic intercalation. It forms a Lewis acid–base Adduct of PbI2·xDMF when PbI2 precipitates from DMF solution. The lattice of PbI2 is expanded more than 30% due to the intercalation of DMF. With the lattice expansion, CH3NH3I (MAI) diffuses into the PbI2·xDMF lattice easily, and the PbI2·xDMF converts completely to CH3NH3PI3 by molecular exchange between DMF and MAI. The lattice volume changes little during the molecular exchange in PbI2·xDMF. Thus, it is easy to fabricate high quality perovskite films from the Lewis Adduct of PbI2·xDMF. The perovskite solar cells fabricated from the Lewis Adduct exhibit higher photovoltaic performance than those from the PbI2 films. This work reveals the important role of common solvent in controlling the quality of perovskite films.
Rajendra S Ghadwal - One of the best experts on this subject based on the ideXlab platform.
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electrophilic terminal arsinidene iron 0 complexes with a two coordinated arsenic atom
Chemical Communications, 2019Co-Authors: Manish Sharma, Beate Neumann, Hansgeorg Stammler, Diego M Andrada, Rajendra S GhadwalAbstract:The first terminal arsinidene complexes [{(NHC)C(Ph)}As]Fe(CO)4 (NHC = IPr = C{(NDipp)CH}25, Me-IPr = C{(NDipp)CMe}26; Dipp = 2,6-iPr2C6H3) with a two-coordinated arsenic atom have been reported as crystalline solids. Calculations suggest that 5 and 6 are electrophilic, which has been demonstrated by the reaction of 5 with an NHC nucleophile (IMe4), affording the Lewis Adduct [{(IPr)C(Ph)}As(IMe4)]Fe(CO)4 (7) (IMe4 = C(NMeCMe)2).
Xiaobing Cao - One of the best experts on this subject based on the ideXlab platform.
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elucidating the key role of a Lewis base solvent in the formation of perovskite films fabricated from the Lewis Adduct approach
ACS Applied Materials & Interfaces, 2017Co-Authors: Xiaobing Cao, Fei Fang, Youwei Yao, Lili Zhi, Xian Cui, Kongxian Ding, Jinquan WeiAbstract:High-quality perovskite films can be fabricated from Lewis acid–base Adducts through molecule exchange. Substantial work is needed to fully understand the formation mechanism of the perovskite films, which helps to further improve their quality. Here, we study the formation of CH3NH3PbI3 perovskite films by introducing some dimethylacetamide into the PbI2/N,N-dimethylformamide solution. We reveal that there are three key processes during the formation of perovskite films through the Lewis acid–base Adduct approach: molecule intercalation of solvent into the PbI2 lattice, molecule exchange between the solvent and CH3NH3I, and dissolution–recrystallization of the perovskite grains during annealing. The Lewis base solvents play multiple functions in the above processes. The properties of the solvent, including Lewis basicity and boiling point, play key roles in forming smooth perovskite films with large grains. We also provide some rules for choosing Lewis base additives to prepare high-quality perovskite fi...
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high quality perovskite films fabricated from Lewis acid base Adduct through molecular exchange
RSC Advances, 2016Co-Authors: Xiaobing Cao, Fei Fang, Xuemin Cui, Youwei Yao, Jinquan WeiAbstract:We describe a facile method to fabricate high quality CH3NH3PbI3 films with smooth surface and without residual PbI2 through molecular exchange, rather than ionic intercalation. It forms a Lewis acid–base Adduct of PbI2·xDMF when PbI2 precipitates from DMF solution. The lattice of PbI2 is expanded more than 30% due to the intercalation of DMF. With the lattice expansion, CH3NH3I (MAI) diffuses into the PbI2·xDMF lattice easily, and the PbI2·xDMF converts completely to CH3NH3PI3 by molecular exchange between DMF and MAI. The lattice volume changes little during the molecular exchange in PbI2·xDMF. Thus, it is easy to fabricate high quality perovskite films from the Lewis Adduct of PbI2·xDMF. The perovskite solar cells fabricated from the Lewis Adduct exhibit higher photovoltaic performance than those from the PbI2 films. This work reveals the important role of common solvent in controlling the quality of perovskite films.
Leitl J. - One of the best experts on this subject based on the ideXlab platform.
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A Phosphinine‐derived 1‐Phospha‐7‐bora‐norbornadiene: Frustrated Lewis Pair Type Activation of Triple Bonds
'Wiley', 2020Co-Authors: Leitl J., Jupp A. R., Habraken E. R. M., Coburger P., Scott D. J., Gschwind, Ruth M., Müller C., Slootweg J. C., Wolf RobertAbstract:Salt metathesis of 2,4,6‐triphosphacyclohexadienyl lithium and chlorobis(pentafluorophenyl)borane affords a 1‐phospha‐7‐bora‐norbornadiene derivative 2 . The C≡N triple bonds of nitriles insert into the P−B bond of 2 with concomitant C−B bond cleavage, while the C≡C bonds of phenylacetylenes react with 2 to form λ 4 ‐phosphabarrelenes. Even though 2 must formally be regarded as a classical Lewis Adduct, the C≡N and C≡C activation processes observed (and the mild conditions under which they occur) are reminiscent of the reactivity of frustrated Lewis pairs. Indeed, NMR and computational studies give insight into the mechanism of the reactions and reveal the labile nature of the phosphorus‐boron bond in 2 , which is also suggested by detailed NMR spectroscopic studies on this compound. Nitrile insertion is thus preceded by ring opening of the bicycle of 2 through P−B bond splitting with a low energy barrier. By contrast, the reaction with alkynes involves formation of a reactive zwitterionic methylphosphininium borate intermediate, which readily undergoes alkyne 1,4‐addition
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A Phosphinine-Derived 1-Phospha-7-Bora-Norbornadiene: Frustrated Lewis Pair Type Activation of Triple Bonds
'Wiley', 2020Co-Authors: Leitl J., Habraken E. R. M., Coburger P., Müller C., Jupp A.r., Scott D.j., Gschwind R.m., Slootweg J.c., Wolf R.Abstract:Salt metathesis of 1‐methyl‐2,4,6‐triphenylphosphacyclohexadienyl lithium and chlorobis(pentafluorophenyl)borane affords a 1‐phospha‐7‐bora‐norbornadiene derivative 2 . The C≡N triple bonds of nitriles insert into the P−B bond of 2 with concomitant C−B bond cleavage, whereas the C≡C bonds of phenylacetylenes react with 2 to form λ4‐phosphabarrelenes. Even though 2 must formally be regarded as a classical Lewis Adduct, the C≡N and C≡C activation processes observed (and the mild conditions under which they occur) are reminiscent of the reactivity of frustrated Lewis pairs. Indeed, NMR and computational studies give insight into the mechanism of the reactions and reveal the labile nature of the phosphorus–boron bond in 2 , which is also suggested by detailed NMR spectroscopic studies on this compound. Nitrile insertion is thus preceded by ring opening of the bicycle of 2 through P−B bond splitting with a low energy barrier. By contrast, the reaction with alkynes involves formation of a reactive zwitterionic methylphosphininium borate intermediate, which readily undergoes alkyne 1,4‐addition
Holger Braunschweig - One of the best experts on this subject based on the ideXlab platform.
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elucidating the reactivity of vicinal dicarbenoids from Lewis Adduct formation to b c bond activation
Chemistry: A European Journal, 2016Co-Authors: Hauke Kelch, Krzysztof Radacki, Stephanie Kachel, Mehmet Ali Celik, Marius Schafer, Benedikt Wennemann, Alex R Petrov, Matthias Tamm, Holger BraunschweigAbstract:The reactivity of the diaminoacetylene Pip-C≡C-Pip (Pip=piperidyl=NC5 H10 ) towards phenyldichloro- and triphenylborane is presented. In the case of the less Lewis acidic PhBCl2 , the first example of a double Lewis Adduct of a vicinal dicarbenoid is reported. For the more Lewis acidic triphenylborane, coordination to the bifunctional carbene leads to a mild B-C bond activation, resulting in a syn-1,2-carboboration. Ensuing cis/trans isomerization yields a novel ethylene-bridged frustrated Lewis pair (FLP). The compounds were characterized using multinuclear NMR spectroscopy, structural analysis, and mass spectrometry. Reactivity studies of both isomers with the N-heterocyclic carbene 1,3-dimethylimidazol-2-ylidene (IMe) aided in elucidating the proposed isomerization pathway. DFT calculations were carried out to elucidate the reaction mechanism. The rather low free energy of activation is consistent with the observation that the reaction proceeds smoothly at room temperature.
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Transmetallation between metal-only Lewis pairs: a new rhodium alane complex.
Chemical Communications, 2012Co-Authors: Jürgen Bauer, Holger Braunschweig, Krzysztof RadackiAbstract:In this communication, synthesis of a rhodium alane Lewis Adduct, [Cp(Me3P)2Rh→AlCl3], is reported. Given that direct synthesis using aluminium trichloride failed, a convenient transmetallation reaction was applied. The new MOLP was analysed by single crystal X-ray diffraction, multinuclear NMR spectroscopy and density functional theory calculations.