Synthesis and characterization of Pd and Pt complexes of 1,3-bis(ferrocenylchalcogeno)propanes: crystal structures of FcSe(CH2)3SeFc and [M{FcE(CH2)3E'Fc}2](PF6)2 (M = Pd, Pt; E, E′ = Se, Te; Fc = [Fe(η5-C5H5)(η5-C5H4)])

Abstract

Reaction of a 1,3-bis(ferrocenylchalcogeno)propane, FcE(CH₂)₃E′Fc (L: E, E′ = Se or Te; Fc = [Fe(η⁵-C₅H₅)(η⁵-C₅H₄)]), with a palladium(II) or platinum(II) precursor [M(NCMe)₄](PF₆)₂ (M = Pd or Pt) in acetonitrile at room temperature led in good yield to the bis-chelate complexes [ML₂](PF₆)₂. The structures of FcSe(CH₂)₃SeFc and all six complexes have been determined by X-ray crystallography. Electrochemical studies showed that electronic communication between ferrocenyl groups, absent in all three bis(ferrocenylchalcogeno)propanes, is established on complexation only for E = Se and E′ = Se or Te, when the through-bond Fe⋯Fe distance is reduced to 13.17 Å or less.