Cu(I) and Ag(I) complexes of chalcogenide derivatives of the organometallic ligand dppf and the dppa analogue

Abstract

New Cu(I) and Ag(I) complexes were prepared by reaction of [M(NCCH 3) 4][X] (M = Cu or Ag; X = BF 4 or PF 6) with the bidentate chalcogenide ligands Ph 2P(E)NHP(E)Ph 2 (E = S, S 2dppa; E = Se, Se 2dppa), and dpspf (1,1′-bis(diphenylselenophosphoryl)ferrocene). Copper and silver behaved differently. While three molecules of either S 2dppa and Se 2dppa bind to a distorted tetrahedral Cu 4 cluster, with deprotonation of the ligand, 1:2 complexes of the neutral ligands are formed with Ag(I), with a tetrahedral coordination of the metal. The [Cu 4{Ph 2P(Se)NP(Se)Ph 2} 3] + clusters assemble as dimers, held together by weak Se⋯Se distances interactions. Another dimer was observed for the [Ag(dpspf)] + cation, with two short Ag⋯Se distances. DFT and MP2 calculations indicated the presence of attracting interactions, reflected in positive Mayer indices (MI). The electrochemistry study of this species showed that both oxidation and reduction took place at silver.