Crystal Structures and Photoluminescence of Two Zinc(II) and Silver(I) Complexes with 6,7-Dicyanodipyridoquinoxaline

Two d(10) metal-organic complexes, [ZnBr2(DICNQ)(2)] (1) and [AgCN(DICNQ)](2) (2), were prepared from ZnBr2 and AgCN with 6,7-dicyanodipyridoquinoxaline (DICNQ) by solvothermal reactions, respectively, and characterized by single-crystal X-ray diffraction analyses, IR spectroscopy, and photoluminescent measurement. Compound 1 crystallizes in monoclinic, space group C2/c with a = 8.436(2), b = 13.011(3), c = 27.565(6) angstrom, beta = 97.90(3)degrees, V = 2997.0(1) angstrom(3), Z = 4, M-r = 789.73, D-c = 1.750 g/cm(3), mu = 3.533 mm(-1), F(000) = 1552, S = 1.007 and T = 293(2) K. The final R = 0.0739 and wR = 0.1380 for 1561 observed reflections with I > 2 sigma(I). Compound 2 crystallizes in monoclinic, space group P2(1)/c with a = 24.202(6), b = 7.1619(17), c = 18.339(5) angstrom, beta = 111.8380(10)degrees, V = 2950.6(1) angstrom(3), Z = 4, M-r = 832.32, D-c = 1.874 g/cm(3), mu = 1.382 mm(-1), F(000) = 1632, S = 1.002 and T = 293(2) K. The final R = 0.0389 and wR = 0.1257 for 4812 observed reflections with I > 2 sigma(I). Both compounds form packing structures by pi center dot center dot center dot pi stacking interactions and C-H center dot center dot center dot N or C-H center dot center dot center dot Br hydrogen-bonding interactions. Compounds 1 and 2 show similar photoluminescent spectra with emission maxima at ca. 430 nm in diluted acetonitrile solution (1 x 10(-5) mol L-1) at room temperature.