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Cooperative Bond Activation and Catalytic Reduction of Carbon Dioxide at a Group 13 Metal Center 下载免费PDF全文
Joseph A. B. Abdalla Dr. Ian M. Riddlestone Rémi Tirfoin Prof. Simon Aldridge 《Angewandte Chemie (International ed. in English)》2015,54(17):5098-5102
A single‐component ambiphilic system capable of the cooperative activation of protic, hydridic and apolar H? X bonds across a Group 13 metal/activated β‐diketiminato (Nacnac) ligand framework is reported. The hydride complex derived from the activation of H2 is shown to be a competent catalyst for the highly selective reduction of CO2 to a methanol derivative. To our knowledge, this process represents the first example of a reduction process of this type catalyzed by a molecular gallium complex. 相似文献
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Dr. Ian M. Riddlestone Philippe Weis Dr. Arthur Martens Marcel Schorpp Dr. Harald Scherer Prof. Dr. Ingo Krossing 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(45):10546-10551
Upon coordinating P4 to electron poor cyclopentadienyl-iron cations, the average P−P bond distances shrink and the respective P4 breathing mode in the Raman spectra (600 cm−1, P4, free) is blueshifted by >40 cm−1 in [CpFe(CO)(L)(η1-P4)]+ cations (L=CO or PPh3). Analysis suggests that this corresponds to an umpolung of the bonding from more phosphidic in the known, electron-rich systems to more phosphonium-like in the reported electron-poor versions. This may open new functionalization pathways for white phosphorus P4. 相似文献
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Lee R. Collins Gabriele Hierlmeier Dr. Mary F. Mahon Dr. Ian M. Riddlestone Prof. Michael K. Whittlesey 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(8):3215-3218
The electrophilic character of free diamidocarbenes (DACs) allows them to activate inert bonds in small molecules, such as NH3 and P4. Herein, we report that metal coordinated DACs also exhibit electrophilic reactivity, undergoing attack by Zn and Cd dialkyl precursors to afford the migratory insertion products [(6‐MesDAC‐R)MR] (M=Zn, Cd; R=Et, Me; Mes=mesityl). These species were formed via the spectroscopically characterised intermediates [(6‐MesDAC)MR2], exhibiting barriers to migratory insertion which increase in the order MR2 = ZnEt2 < ZnMe2 < CdMe2. Compound [(6‐MesDAC‐Me)CdMe] showed limited stability, undergoing deposition of Cd metal, by an apparent β‐H elimination pathway. These results raise doubts about the suitability of diamidocarbenes as ligands in catalytic reactions involving metal species bearing nucleophilic ligands (M‐R, M‐H). 相似文献
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Philippe Weis Dr. Ian M. Riddlestone Dr. Harald Scherer Prof. Dr. Ingo Krossing 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(52):12159-12168
The complexes Ag(L)n[WCA] (L=P4S3, P4Se3, As4S3, and As4S4; [WCA]=[Al(ORF)4]− and [F{Al(ORF)3}2]−; RF=C(CF3)3; WCA=weakly coordinating anion) were tested for their performance as ligand-transfer reagents to transfer the poorly soluble nortricyclane cages P4S3, P4Se3, and As4S3 as well as realgar As4S4 to different transition-metal fragments. As4S4 and As4S3 with the poorest solubility did not yield complexes. However, the more soluble silver-coordinated P4S3 and P4Se3 cages were transferred to the electron-poor Fp+ moiety ([CpFe(CO)2]+). Thus, reaction of the silver salt in the presence of the ligand with Fp−Br yielded [Fp−P4S3][Al(ORF)4] ( 1 a ), [Fp−P4S3][F(Al(ORF)3)2] ( 1 b ), and [Fp−P4Se3][Al(ORF)4] ( 2 ). Reactions with P4S3 also yielded [FpPPh3−P4S3][Al(ORF)4] ( 3 ), a complex with the more electron-rich monophosphine-substituted Fp+ analogue [FpPPh3]+ ([CpFe(PPh3)(CO)]+). All complex salts were characterized by single-crystal XRD, NMR, Raman, and IR spectroscopy. Interestingly, they show characteristic blueshifts of the vibrational modes of the cage, as well as structural contractions of the cages upon coordination to the Fp/FpPPh3 moieties, which oppose the typically observed cage expansions that lead to redshifts in the spectra. Structure, bonding, and thermodynamics were investigated by DFT calculations, which support the observed cage contractions. Its reason is assigned to σ and π donation from the slightly P−P and P−E antibonding P4E3-cage HOMO (e symmetry) to the metal acceptor fragment. 相似文献
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