Synthesis and characterization of (H2dab)2Cu8Ge4S14•2H2O: An expanded framework based on icosahedral Cu8S12 cluster

A new three-dimensional framework copper-thiogermanate, (H(2)dab)(2)Cu8Ge4S14 center dot 2H(2)O (1), was prepared under solvothermal condition and characterized by elemental analysis, single-crystal and powder X-ray diffraction, thermogravimetric analysis and UV-vis diffuse reflectance spectroscopy. Compound 1 crystallizes in the monoclinic space group P2(1)/c, a=11.444(4) angstrom, b=12.984(4) angstrom, c=12.455(6) angstrom, beta=91.527(1)degrees, V=1850.2(3)angstrom(3), Z=2. It contains a new three-dimensional Cu-Ge-S framework constructed from icosahedral [Cu8S12](16-) clusters linked by [GeS4](4-) and dimeric [Ge2S6](4-) units, with diprotonated 1,4-dab (1,4-diaminobutane) and H2O molecules located in the intersecting channels. UV-vis reflectance spectroscopy reveals the band gap of compound 1 is 2.5 eV. (C) 2011 Elsevier Inc. All rights reserved.