New phosphino silver(I) derivatives of hydrotris(3-methyl-2-thioxo-1-imidazolyl)borate. X-ray crystal structure of tricyclohexylphosphine-silver(I)-hydrotris(3-methyl-2-thioxo-1-imidazolyl)borate

1.1 Triorganophosphine silver(I) adducts containing the anionic, potential S-3-donor, hydrotris(3-methyl-1-imidazolyl-2-thioxo)borate (Tm) were synthesized from K[Tm], AgNO3 and tricyclohexylphosphine (PCy3), tribenzylphosphine (PBz(3)), tri-p-tolylphosphine (P(p-tolyl)(3)), tris(2,4,6-trimethylphenylphosphine) (PMes(3)) or ethyldiphenylphosphine (PEtPh2). When methyldiphenylphosphine (PMePh2) reacted with K[Tm] and AgNO3 the 1:1:2 adduct [(Tm)Ag{PMePh2}(2)] was obtained, whereas P(m-tolyl)3 in the same conditions yielded the 2:1:1 [(Tm)(2)Ag-2{P(m-tolyl)(3)}] complex. The bidentate phosphorus donors 1,2-bis(diphenylphosphino)ethane (DPPE) and 1,1'-bis(diphenylphosphino)ferrocene (DPPF) reacted with the [(Tm)Ag] moiety yielding the 1:1:1 adducts [(Tm)Ag(DPPE)] and [(Tm)Ag {DPPF}] whereas no adduct was obtained with 1,3-bis (diphenylphosphino)propane and 1,3-bis(diphenylphosphino)butane. All the complexes synthesized were characterized through analytical and spectral (IR, H-1, C-13 and (31)p) measurements. The solid state structure of [(hydrotris(3-methyl-1-imidazolyl-2-thioxo)-borate)silver(I) {tricyclohexylphosphine}] [(Tm)Ag{PCy3}] shows the silver atom tricoordinate with the donor Tm acting in the S-2-bidentate form. The short Ag-B contact distance suggests the existence of a two-electron B-H ... Ag agostic interaction. (C) 1999 Elsevier Science S.A. All rights reserved.