Complexes of platinum(ii) containing ferrocenylethynyl ligands: synthesis, characterization and spectroscopic and electrochemical properties

Abstract

A series of homoleptic and heteroleptic platinum(II) complexes [Pt(CCFc)₂(L-L)] (L-L = COD 1, 1,1′-bis(diphenylphosphino)ferrocene (dppf) 2), Q₂[cis/trans-Pt(C₆F₅)₂(CCFc)₂] (cis, Q = PMePh₃, 3; trans, Q = NBu₄, 4), (NBu₄)[Pt(bzq)(CCFc)₂] 5 (Hbzq = 7,8-benzoquinoline) and (NBu₄)₂[Pt(CCFc)₄] 6 has been synthesized and characterized spectroscopically and the structures of 1·2CHCl₃, 2 and 6·2H₂O·2CH₂Cl₂ confirmed by single-crystal X-ray studies. The anion of complex 6, shows strong O–H⋯π(CC) interactions and weaker C–Cl⋯π(CC) contacts between the protons of two water and two CH₂Cl₂ molecules and the C_αC_β of mutually cis alkynyl groups. In this complex the presence of additional O–H⋯H–C(Cp) and C–Cl⋯H–C(Cp) contacts gives rise to an extended bidimensional network. The optical and electrochemical properties of all derivatives have been examined. It is remarkable that for complexes 2 and 5 a facile oxidatively induced coupling, giving rise to 1,4-diferrocenylbutadiyne, is observed, this also having been proven by chemical oxidation.