Solution and solid-state structural properties of silver(I) poly(pyrazolyl)borate compounds with bidentate diphosphines

New silver(I) derivatives containing bidentate tertiary phosphines and anionic poly(pyrazol-1-yl)borates have been prepared from AgNO3 and bis(diphenylphosphino)methane (dppm), 1,2-bis(diphenylphosphino)ethane (dppe), 1,3-bis(diphenylphosphino)propane (dppp), 1,4-bis(diphenylphosphino)butane (dppb) or 1,1′-bis(diphenylphosphino)ferrocene (dppf) and K[H2B(pz)2], K[H2B(3,5-Me2pz)2], K[B(pz)4] or K[B(3-Mepz)4] (pzH=pyrazole); their solid state and solution properties have been investigated through analytical and spectroscopic measurements (IR, 1H and 31P NMR). The 1H and 31P NMR spectra have been interpreted with equilibria that involve mono- and di-nuclear complexes, or the presence of 1:1 and 1:2 silver-diphosphine species. The compounds are soluble in chlorinated solvents and are non-electrolytes in CH2Cl2 and acetone solutions. The structures of [(dppf){Ag(pz)2BX2}], X=H, pz have been determined by single crystal X-ray studies, the poly(pyrazolyl)borates being always bidentate with the silver(I) centers in distorted tetrahedral geometries.