Metal dithiocarbamates and related complexes. Part I. Reactions of tris(dithiocarbamato)nickel(IV) cations with Lewis bases

Abstract

Treatment of [Ni(S₂CNR₂)₃][PF₆](R = Et or Buⁿ) with Lewis bases [L = CNR′(R′= Prⁱ, Bu^t, or C₆H₄Cl-p), PMePh₂, or ½Ph₂PCH₂CH₂PPh₂(dppe)] gives [NiL₂(S₂CNR₂)][PF₆]; when L = CNR′, the thiuram disulphide (R₂NCS₂)₂ has been also isolated. Reaction of [Ni(S₂CNR₂)₃][PF₆] with PPh₃ affords PPh₃S, [PPh₃{C(NR₂)S}]-[PF₆], and [Ni(S₂CNR₂)₂]; only very low yields of [Ni(PPh₃)₂(S₂CNR₂)][PF₆] have been isolated. Similar products have been obtained in the reaction between [Ni(PPh₃)₂(S₂CNEt₂)][PF₆] and (Et₂NCS₂)₂. The species [NiL₂(S₂CNR₂)][PF₆](L = PMePh₂ or PPh₃) have been obtained from [NiL(S₂CNR₂)X](X = halide), L, and M[PF₆](M = K, Tl, or Ag), and modified procedures for making [NiL(S₂CNR₂)X] are described. Reaction of [Ni(PPh₃)(S₂CNR₂)][PF₆] with PMePh₂ gives [Ni(PMePh₂)(S₂CNR₂)X](X = 1), and with Tl(C₅H₅) and Na[SR″] the complexes [Ni(η-C₅H₅)I(PPh₃)] and [{Ni(SR″)(S₂CNR₂)}₂](R″= Me, Pr_i, Bu_t, PhCH₂, or Ph) are formed, respectively. The n.m.r., electronic, and i.r. spectral properties of these complexes are discussed. The complex [NiCl(PPh₃)(S₂CNEt₂)] readily undergoes phosphine exchange with free PPh₃, and while [Nil(dppe)(S₂CNBuⁿ₂)] is four-co-ordinate (iodide salt) in chlorinated hydrocarbon and polar sovents it is apparently five-co-ordinate in benzene.