CRYSTALLOGRAPHIC, THEORETICAL, AND SPECTROSCOPIC STUDIES OF THE LUMINESCENT D(10)-D(10) BINUCLEAR COPPER-ACETATE COMPLEX CU-2(DPPM)(2)(O2CCH3)(+)

The new d(10)-d(10) dimer Cu-2(dppm)(2)(O2CCH3)(+) (as a BF4- salt) ha s been prepared and characterized by X-ray crystallography and by H-1 and P-31 NMR, vibrational, and electronic spectroscopy. The compound i s luminescent at 77 K but not at room temperature. MO calculations and geometry optimizations have been performed using the EHMO and DFT mod els, respectively. In the solid state the Cu-2 separation is 2.788(1) Angstrom. where nu(Cu-2) = 87.7 cm(-1), indicating the presence of wea k Cu ... Cu interactions. The MO calculations predict that the lowest energy excited states are MLCT from Cu to phenylphosphine/acetate. The se predictions have been confirmed by electronic spectroscopy via a co mparison between Cu-2(dppm)(2)(O2CCH3)(+) and Cu-2(dppm)(2)(O2CC6H5)() In solutions, both NMR (H-1 and P-31) and luminescence spectroscopie s (time-resolved spectra and tau(e) analysis) demonstrate the presence of two metal species in solutions: Cu-2(dppm)(2)(O2CCH3)(+) and Cu-2( dppm)(O2CCH3)(+). The dimer crystallizes in the triclinic space group P (1) over bar with a = 11.572(2) Angstrom, b = 12.552(2)Angstrom, c = 19.543(3) Angstrom, alpha = 85.274(12)degrees, beta = 82.108(11)degre es, gamma = 68.950(12)degrees, and Z = 2.