Metal dithiocarbamates and related complexes. Part 2. Reactions of iron complexes with Lewis bases and with zinc iodide, and the structure of [Fe{CN(p-ClC6H4)}2(S2CNEt2)2ZnI2]

Abstract

Reactions of [Fe(S₂CNEt₂)₃]^+,0, [FeI(S₂CNEt₂)₂], and [Fe(S₂CNEt₂)₂] with Ph₂PCH₂CH₂PPh₂(dppe), CNR, and PPh₃ are described. The complexes [Fe(dppe)(S₂CNEt₂)₂]^+,0, [Fe(CNR)₂(S₂CNEt₂)₂]^z(z=+1, R =p-ClC₆H₄; z= 0, R = Prⁱ, Bu^t, or p-ClC₆H₄), and [Fe{CN(p-ClC₆H₄)}₄(S₂CNEt₂)]⁺ were characterised analytically, spectrally, and voltammetrically. Treatment of [Fe(S₂,CNEt₂)₃]⁺ with PPh³ afforded [Fe(S₂CNEt₂)₃], PPh₃S, and [PPh₃{C(NEt₂)S}]⁺. An equilibrium is established, under nitrogen, between mixtures of [Fe(S₂CNEt₂)₃] and Znl₂ with [FeI(S₂CNEt₂)₂] and [Zn(S₂CNEt₂)₂]; in air, the first two afforded, inter alia[Znl₂(Et₂NCS₂)₂].

[Fe{CN(p-ClC₆H₄)}₂(S₂CNEt₂)₂] reacted with Znl₂ giving [Fe{CN(p-ClC₆H₄)}₂(S₂CNEt₂)₂Znl₂]. An X-ray crystallographic examination of this compound revealed that it had crystallographically imposed C₂ symmetry, the Fe atom having a distorted octahedral geometry consisting of two mutually cis p-ClC₆H₄NC groups and two bidentate dithiocarbamato-ligands. One sulphur atom of each S₂CNEt₂ group formed a bridge to the zinc atom, the distorted tetrahedral geometry of which was completed by the two iodine atoms. The relationship of this structure to the possible mechanism of ligand exchange between [Fe(S₂CNEt₂)₃] and Znl₂ is briefly discussed.