Interplay between Organic–Organometallic Electrophores within Bis(cyclopentadienyl)Molybdenum Dithiolene Tetrathiafulvalene Complexes

Tetrathiafulvalenes
(TTF) and bis­(cyclopentadienyl) molybdenum
dithiolene complexes, Cp2Mo­(dithiolene) complexes, are
known separately to act as good electron donor molecules. For an investigation
of the interaction between both electrophores, two types of complexes
were synthesized and characterized. The first type has one Cp2Mo fragment coordinated to one TTF dithiolate ligand, and
the second type has one TTF bis­(dithiolate) bridging two Cp2Mo fragments. Comparisons of the electrochemical properties of these
complexes with those of models of each separate electrophore provide
evidence for their mutual influence. All of these complexes act as
very good electron donors with a first oxidation potential 430 mV
lower than the tetrakis­(methylthio)­TTF. DFT calculations suggest that
the HOMO of the neutral complex and the SOMO of the cation are delocalized
across the whole TTF dithiolate ligand. The X-ray crystal structure
analyses of the neutral and the mono-oxidized Cp2Mo­(dithiolene)­(bismethylthio)­TTF
complexes are consistent with the delocalized assignment of the highest
occupied frontier molecular orbitals. UV–vis–NIR spectroelectrochemical
investigations confirm this electronic delocalization within the TTF
dithiolate ligand.