Synthesis and spectroscopic studies of silver and rhodium mono- and polynuclear complexes with multidentate phosphines (Ph2P)2CHR (R = H, Me, PPh2)

Abstract

Trinuclear [{(Ph{2}P){3}CH}Ag{3}(O{2}CR'){3}], dinuclear [{(Ph{2}P){2}CHR}Ag{2}(O{2}CR'){2}], [{(Ph{2}P){2}CHR}{2}Ag{2}](BF{4}){2} and (Rh{2}(Cl)(CO){2}{(Ph{2}P){2}CHMe}{2}][RhCl{2}(CO){2}], and mononuclear (Rh{(Ph{2}P){2}CHR}{2}](BF{4}), (Rh{(Ph{2}P){2}CHR}{2}HCl](BF{4}), d [Rh{(Ph{2}P){2}CHR}{2}Cl(HgCl)](BF{4}) and (Rh{(Ph{2}P){2}CHR}{2}O{2}](BF{4}) (R = H,Me) were synthesized from the phosphines tris(diphenylphosphino)methane ((Ph{2}P){3}CH), bis(diphenylphosphino)methane ((Ph{2}P){2}CH{2}) and 1,1-bis(diphenylphosphino)ethane ((Ph{2}P){2}CHMe). The }1{H, }1{}3{C and }3{}1{P NMR spectra were investigated and for the mononuclear rhodium compounds compared with their 1,2-bis(diphenylphosphino)ethane and 1,3-bis(diphenylphosphino)propane analogues. The }3{}1{P NMR spectra of the silver complexes revealed besides normal values for J(}1{}0{}7{Ag-}3{}1{P) (640 and 500 Hz for the gAgP and AgP{2} systems, respectively) a small{3}J(}1{}0{}7{Ag-{3}{1}P) of about -4 Hz and an exceptionally large }2{J(}3{}1{P-}3{}1{P) of 170 Hz. A large positive charge on the P-atoms in [{(Ph{2}P){2}CH{2}}Ag{2}(O{2}CR){2}] and [{(Ph{2}P){2}CH{2}}Ag{2}](BF{4}){2} was calculated from the chemical shifts of the methylene protons.On the basis of }3{}1{P NMR data methyl substitution in (Ph{2}P){2}CHR resulted in formation of only one of the possible isomers for [{(Ph{2}P){2}CHMe}{2}Ag{2}](BF{4}){2}, [Rh{2}(CO){2}(Cl){(Ph{2}P){2}CHMe}{2}][RhCl{2}(CO){2}] and [Rh{(Ph{2}P){2}CHMe}{2}O{2}](BF{4}), but two isomers for [Rh{(Ph{2}P){2}CHMe}{2}](BF{4}) and [Rh{(Ph{2}P){2}CHMe}HCl](BF{4}). These results are interpreted in terms of metal@?chelate ring puckering.