Electronic Structure of Re 2 (O 2 CR) 4 Cl 2 Complexes (R = H, CMe 3 ) and Reassignment of the Electronic Absorption Spectrum of Re 2 (O 2 CCMe 3 ) 4 Cl 2 .

Electronic structure calculations on two dinuclear rhenium(III) carboxylate complexes, Re 2 (O 2 CH) 4 Cl 2 and Re 2 (O 2 CCMe 3 ) 4 Cl 2 , are presented and discussed. Allowed electronic transitions for both molecules were calculated using time-dependent density functional theory (TDDFT). The results for the pivalate dimer, Re 2 (O 2 CCMe 3 ) 4 Cl 2 , are compared with previously reported single-crystal polarized absorption spectra obtained by Martin and co-workers (Inorg. Chem.1984, 23, 699-701). Several revisions to the previous spectral assignments are proposed.