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

Abstract

The reactions of m-H2BDC, NaOH with Cd(NO3)2 · 4H2O and Co(NO3)2 · 4H2O (m-BDC = 1,3-benzene-dicarboxylate) in DMF gave two isostructural three-dimensional (3D) heterometallic coordination polymers: [CdNa(m-BDC)2] · [NH2(CH3)2] (1) and [CoNa(m-BDC)2] · [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 > 2σ(I) for 1; and R = 0.0654 and wR = 0.1591 using 1881 reflections with I > 2σ(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.