Strong Electronic Coupling between Dimolybdenum Units Linked by the <i>N</i>,<i>N</i>‘-Dimethyloxamidate Anion in a Molecule Having a Heteronaphthalene-like Structure

Very strong electronic communication, manifested in a KC value of ca. 109, has been found in a system of three compounds separated by one electron oxidation where each compound contains two metal−metal bonded Mo2n+ units linked by a dimethyloxamidate anion, CH3N(O)C−C(O)NCH32-. The Mo−Mo distances increase as the oxidation state increases and the bond order decreases, while the diamagnetic, doubly oxidized species becomes essentially planar and resembles a naphthalene molecule. Calculations at the DFT level indicate that a strong transition in the near-IR region, shown by the singly oxidized and paramagnetic species, is best described as a HOMO−1 → SOMO transition.