Synthesis, structure and property of metal thiophene 2,5-dicarboxylates: Novel three dimensional coordination polymers

Two isostructural novel coordination polymers M2(tdc)2(H2O)3 (H2tdc = thiophene-2,5-dicarboxylic acid, M = Co 1 and Mn 2) have been hydrothermally synthesized and characterized by elemental analyses, IR and X-ray powder diffraction. Compound 1 has been characterized by single-crystal X-ray diffraction and it crystallizes in the monoclinic system, space group C2/c, a = 19.74(3) Å, b = 7.506(11) Å, c = 10.750(16) Å, β = 103.65(2)°, V = 1548(4) Å3, Z = 4, and R1(wR2) = 0.0546 (0.1175). In compound 1, thiophene-2,5-dicarboxylic dianions exhibit a uniform inequivalent tetradentate coordination mode and cross-link one dimensional Co⋯Co⋯Co pseudochains to form a novel three dimensional framework. Compound 1 exhibits good photoluminescence property, whereas compound 2 is nonemissive at room temperature.