Expanding the Chemistry of Rhenium Metal–Metal Bonded Fluoro Complexes: Facile Preparation and Characterization of Paddlewheel Complexes

Quadruply bonded rhenium(III) dimers with the stoichiometry Re 2 L 4 F 2 (1, L = hexahydro-2H-pyrimido[1,2a]pyrimidinate (hpp - ); 2, L = diphenyl formamidinate (dpf - )) were prepared from the solid-state melt reactions (SSMRs) between (NH 4 ) 2 [Re 2 F 8 ]·2H 2 O and HL. Those compounds were characterized in the solid state by single-crystal X-ray diffraction and in solution by UV-visible spectroscopy and cyclic voltammetry. The compound [Re 2 (hpp) 4 F 2 ]PF 6 (3) was prepared from the one-electron oxidation of Re 2 (hpp) 4 F 2 with [Cp 2 Fe]PF 6 . Compounds 1-3 are isostructural with the corresponding chloro derivatives. In solution, compound 1 undergoes two one-electron oxidations. Comparison with its higher halogen homologues reveals that Re 2 (hpp) 4 F 2 (1) is more easily oxidized than its chloro and bromo analogues.