Stepwise isolation of an unprecedented silylene supported dinuclear gold(I) cation with aurophilic interaction

Abstract

The silylene (PhC(NtBu)2SiN(PPh2)(2,6-iPr2-C6H3)) (2) was prepared from the previously reported (PhC(NtBu)2SiCl) salt elimination method. The reaction of 2 with AuCl(SMe2) afforded [(PhC(NtBu)2SiN(PPh2)(2,6-iPr2-C6H3))AuCl] (3). Note here that only Si(II) is coordinated to Au(I), while P(III) remains uncoordinated. The higher negative value of the electrostatic potential (ESP) at the Si-centre (−28.8 kcal mol−1) as compared to that at the P-centre (−15.3 kcal mol−1) justifies this observation. Furthermore, the chloride abstraction from 3 by AgSbF6 led to the formation of a dinuclear Au(I) cationic complex, [PhC(NtBu)2Si(2,6-iPr2-C6H3NPPh2)(Au)]2[SbF6]2 (4), which displays an intra-molecular Au⋯Au interaction of 2.865 Å.