Metal dithiocarbamates and related species. Part 2. Reaction of zinc thiuram disulphides with triphenylphosphine and other Lewis bases, and anionic dithiocarbamato-complexes of zinc

Abstract

Reaction of [ZnI2{(S2CNMe2)2}] with 1, 2, and 3 mol of PPh3 gives [ZnI2{S(SCNMe2)2}], [PPh3{C(NMe2)S}][ZnI2(S2CNMe2)], and [PPh3{C(NMe2)S}][ZnI3(PPh3)], respectively, together with PPh3S and small amounts of [ZnI2(PPh2)2]. These reactions can be carried out in steps, and the identity of the products has been confirmed by independent synthesis and spectral methods. The species [ZnX2{S(SCNMe2)2}](X = Cl or Br), [NBun4]ZnX2(S2CNMe2)](X = Cl, Br, or I), and [PPh3{C(NMe2)S}]X (X = PF6 or I) have been prepared. The cation [PPh3{C(NMe2)S}]+ reacts with [S2CNMe2]– giving S(SCNMe2)2 and PPh3. Treatment of [Zn(S2CNRR′)2] with [S2CNRR′]– affords [Zn(S2CNRR′)3]–(R = R′= Me; R = Me, R′= Ph; isolated as [NEt4]+ or [NBun4+ salts), while [Zn(S2CNR2)2](R = Et or Bun) react with [S2CNMe2]– affording [Zn(S2CNEt2)2(S2CNMe2)]– or [Zn(S2CNBun2)(S2CNMe2)2]–, respectively. Treatment of [Zn(S2CNMe2)2] with [NBun4][O2CMe] afforded [NBun4][Zn(O2CMe)(S2CNMe2)2]. Possiblemechanismsfortheattackof PPh3 on metal-co-ordinated (R2NCS2)2 and S(SCNR2)2 are discussed, and brief comments are made on the relation of species such as [Zn(O2CR′)(S2CNR2)2]– to the acceleration of vulcanisation of natural rubber.