Reactions between bis(O-alkyl dithiocarbonato)nickel(II) complexes and phosphines. Formation of a dithiocarbonate complex of nickel(II): [Ni(S2CO)(Ph2PCH2CH2PPh2)]

Abstract

The behaviour of O-alkyl dithiocarbonato complexes, [Ni(S₂COR)₂], towards several phosphines has been studied. Depending on the S₂COR derivative and phosphine (L) used, octahedral complexes [Ni(S₂COR)₂L₂][R = cyclo-C₆H₁₁, L₂= Ph₂PCH₂CH₂PPh₂(dppe); R = Et, L = PMePh₂], paramagnetic five-co-ordinate complexes [Ni(S₂COR)₂(dppe)] and square-planar [Ni(S₂COR)₂(PMe₂Ph)₂](R = Et or cyclo-C₆H₁₁) and [Ni(S₂COC₆H₁₁)₂(PMePh₂)] complexes have been obtained. The reaction of [Ni(S₂COR)₂](R = Me, Et, or cyclo-C₆H₁₁) with and excess of dppe gives [Ni(S₂CO)(dppe)] which is the first Ni^II–dithiocarbonate complex described. This compound reacts with MeI and C₃H₅Br to give [NiX₂(dppe)](X = I or Br). There is no reaction with Lewis-base N donors or with carbon monoxide.