From As-Zincoarsasilene (LZn-As=SiL ') to Arsaethynolato (As equivalent to C-O) and Arsaketenylido (O=C=As) Zinc Complexes

摘要

The reactivity of the As-zincosilaarsene LZn-As=SiL ' A (L=[CH(CMeNDipp)(2)](-), Dipp=2,6-(Pr2C6H3)-Pr-i, L '=[{C(H)N(2,6-Pr-i(2)-C6H3)}(2)](2-)) towards small molecules was investigated. Due to the pronounced zwitterionic character of the Si=As bond of A, it undergoes addition reactions with H2O and NH3, forming LZnAs(H)SiOH(L ') 1 and LZnAs(H)SiNH2(L ') 2. Oxygenation of A with N2O at -60 degrees C furnishes the deep blue 1,2-disiloxydiarsene, [LZnOSi(L ')As](2) 4, presumably via dimerization of the arsinidene intermediate LZnOSi(L ')As 3. Oxygenation of A with CO2 leads to the monomeric arsaethynolato siloxido zinc complex LZnOSi(L ')(OC equivalent to As) 5, essentially trapping the intermediary arsinidene 3 with liberated CO following initial oxidation of the Si=As bond. DFT calculations confirm the ambident coordination mode of the anionic [AsCO] ligand in solution, with the O-arsaethynolato [As equivalent to C-O](.-) in 5, and the As-arsaketenylido ligand mode [O=C=As](-) present in LZnO-Si(L ')(-As=C=O) 5 ' akin to the analogous phosphorus system, [PCO](-).