Bis(trifluoromethyl)dithiolene tricarbonyl iron and its Lewis base derivatives

Abstract

Reaction of Fe₂(CO)₉ with S₂C₂(CF₃)₂ under mild conditions gives [Fe(CO)₃{S₂C₂(CF₃)₂}]_n. On the basis of i.r. and electronic spectral, and solution molecular-weight studies, n is thought to be 2 in solution; n= 2 in the solid state. The complex reacts with Lewis bases, L, giving [Fe(CO)_{3 –n}(PPh₃)_n{S₂C₂(CF₃)₂}](n= 1 or 2), [Fe(CO)_{3 –n}L_n-{S₂C₂(CF₃)₂}][L = CN(Bu^t), CN(p-ClC₆H₄), or P(OEt)₃], [Fe(CO)(LL′){S₂C₂(CF₃)₂}][LL′=cis-Ph₂PCH:-CHPPh₂, Ph₂PCH₂CH₂PPh₂, or o-C₆H₄(AsMe₂)₂], [Fe{P(OEt)₃}(LL′)-{S₂C₂(CF₃)}](LL′= Ph₂PCH₂CH₂PPh₂), and [Fe(NO)(LL′){S₂C₂(CF₃)₂}]^z(LL′=cis-Ph₂PCH:CHPPh₂ or Ph₂PCH₂CH₂PPh₂; z= 0 or +1). All species except the parent complex were thought to have square-pyramidal geometries. Only the complexes [Fe(NO)(LL′)-{S₂C₂(CF₃)₂}]^o and [Fe(CO)(PPh₃)₂{S₂C₂(CF₃)₂}]⁰ exhibited reversible one-electron voltammetric oxidation waves.