Synthesis and Characterization of Dibenzoheterocycle-Bridged Dinuclear Ruthenium Alkynyl and Vinyl Complexes

A series of dinuclear ruthenium alkynyl and vinyl complexes bridged by carbazole, dibenzofuran, dibenzothiophene, and fluorenone have been prepared, and some representative molecular structures have been determined. The electro-chemical and spectroscopic properties of the compounds were explored by cyclic voltammetry (CV), square-wave voltammetry (SWV), and in situ infrared and UV/Vis/near-IR spectroelectrochemical methods. The electrochemical results indicate that the greater the electron density on the ligand, the more stable the bridge-based oxidation product and the larger the electrochemical splitting. The UV/Vis/near-IR spectroelectrochemical studies revealed that the bridged ligands strongly contribute to or even dominate the oxidation processes. In addition, IR spectroelectrochemistry strengthens the theory of redox noninnocence in the bridging ligands, which was further confirmed by DFT calculations.