Ferrocene-dithiolene hybrids: control of strong donor-acceptor electronic communication to reverse the charge transfer direction.

We prepared a novel class of ferrocene–dithiolene hybrid molecules, FcS4dt(Me)2 and FcS4dt[Pt(tBu2bpy)] (where FcS4dt indicates 2-(1,3-dithia[3]ferrocenophane-2-ylidene)-1,3-dithiole-4,5-dithiolate and tBu2bpy indicates 4,4′-di-tert-butyl-2,2′-bipyridine), in which the ferrocene moiety was bound to the planar conjugated dithiolene skeleton via two sulfur atoms such that the cyclopentadienyl rings were perpendicular to the dithiolene backbone. The physical properties and electronic structures of the complexes and their oxidized species [FcS4dt(Me)2]•+ and [FcS4dt[Pt(tBu2bpy)]]•+ were investigated by means of single-crystal X-ray diffraction (XRD) analysis, cyclic voltammetry, electron paramagnetic resonance (EPR), and UV–vis near infrared (UV–vis–NIR) spectroscopy. The electron density distributions of the highest occupied molecular orbitals (HOMOs) of FcS4dt(Me)2 and FcS4dt[Pt(tBu2bpy)] differed remarkably in that the HOMO of the former was ferrocene-based whereas that of the latter was dithiolene-based. ...