Solvothermal syntheses, structures, and luminescence of two heterometallic metal-organic frameworks constructed from m-BDC (m-BDC=1,3-benzene-dicarboxylate)

The reactions of m-H2BDC, NaOH with Cd(NO3)(2) center dot 4H(2)O and Co( NO3)(2) center dot 4H(2)O (m-BDC=1,3-benzene-dicarboxylate) in DMF gave two isostructural three-dimensional (3D) heterometallic coordination polymers: [CdNa(m-BDC)(2)] center dot [NH2(CH3)(2)] (1) and [CoNa(m-BDC)(2)]center dot[NH2(CH3)(2)] (2), respectively. The compounds were characterized by single- crystal X- ray diffraction, X- ray powder diffraction, ICP, TGA, IR, and photoluminescence spectroscopy. The crystal structures were determined by X- ray diffraction and refined by full- matrix least- squares methods to R=0.0221 and wR=0.0579 using 1925 reflections with I>2 sigma(I) for 1; and R=0.0654 and wR=0.1591 using 1881 reflections with I>2 sigma(I) for 2. Their frameworks are constructed from M-O-C (M=Na, Cd and Co) chains composed of alternating six-coordinate Na(I) centers and four- coordinate Cd( II) or Co( II) centers. These chains are further linked by m- BDC to form unusual 3D open- framework structures.