Purification and X-ray crystal structure of bis[tris(trimethylsilyl)methyl]diarsene

Abstract

The crystal and molecular structure of (Me₃Si)₃CAsAsC(SiMe₃)₃ has been determined by X-ray diffraction. The diarsene crystallizes in space group P(no. 2), with a= 9.151 (3), b= 12.682(2), c= 15.537(4)Å, α= 70.07(2), β= 89.61(2), γ= 87.88(2)°, and Z= 2. The compound is isostructural with (Me₃Si)₃CPPC(SiMe₃)₃ and adopts a trans-planar conformation with AsAs = 2.245(1), 2.243(1)Å and As–As–C = 106.2(2), 106.4(2)° In two crystallographically independent molecules. Trends in the structures of REE′R′[EE′N or P, RR′C₆H₂Bu^t₃–2,4,6; EE′P, RR′C(SiMe₃)₃ or NBu^t(SiMe₃); EE′As, RR′C(SiMe₃)₃ or RC₆H₂Bu^t₃–2,4,6,R′CH(SiMe₃)₂; EP,E′As, RC₆H₂Bu^t₃–2,4,6,R′CH(SiMe₃)₂] are discussed.