Solution and solid-state structural properties of silver(I) dihydrobis(pyrazolyl)borate compounds with tertiary mono(phosphine) ligands

Abstract

New silver(I) derivatives containing triorganophosphines and anionic dihydrobis(pyrazol-1-yl)borates have been prepared from AgNO₃ and PR₃ (R = phenyl, benzyl, cyclohexyl, o-, m- or p-tolyl) or PPh₂R′ (R′ = methyl or ethyl) and K[H₂B(pz)₂] or K[H₂B(3,5-Me₂pz)₂] (Hpz = pyrazole); their solid state and solution properties have been investigated through analytical and spectroscopic measurements (IR, ¹H and ³¹P NMR). The compounds are stable, soluble in chlorinated solvents and non-electrolytes in CH₂Cl₂ and acetone solutions. The structures of [Ag{H₂B(pz)₂}(PPh₃)₂], [Ag{H₂B(3,5-Me₂pz)₂}(PEtPh₂)], and [Ag{H₂B(3,5-Me₂pz)₂}(PCy₃)] have been determined by X-ray crystallographic studies. In these compounds the dihydrobis(pyrazol-1-yl)borate ligand is bidentate, with the silver(I) centre adopting a tetrahedral (first) or trigonal geometry (last two).