Synthesis and characterization of the mixed-valence copper complex trichlorobis(4-methyl-1,8-naphthyridine)dicopper

The binuclear complex trichlorobis(4-methyl- 1,8-naphthyridine)dicopper has been prepared and characterized by x-ray diffraction and ESR spectroscopy. The emerald green crystals conform to monoclinic space group P21/c with a = 11.795 (5), b = 14.850 (5), c = 11.320 (5) A, /3 = 99.20 (9)O, Z = 4. The structure. refined to a final conventional R value of 0.05 1 on 281 5 counter data, consists of dimeric molecules containing two equivalent copper atoms in pseudotetrahedral environments, bridged by one chlorine atom and by two 4-methyl-1 $-naphthyridine ligands, which act as bidentate bimetallic ligands. The equivalence of the two copper atoms is substantiated by the ESR spectra. The electronic structure of the complex is also discussed.