Structural Diversity and Luminescence Properties of Coordination Polymers Built With a Rigid Linear Dicarboxylate and Zn(II)/Pb(II) Ion

A rigid linear incorporating a carboxylic acid group at either end, p-terphenyl-4,4 ''-dicarboxylic acid, 2',5'-dimethyl (H2L) has been used to construct four coordination polymers with Zn(II) through solvothermal techniques. The four products formed are formulated as {[Zn-3(L)(2)(OH)(2)]center dot 8EtOH center dot 4DMF}(n) (1), {[Zn(L)bpmp)(0.5)]center dot EtOH center dot 1/2DMF}(n) (2), {(Zn)(0.5)(L)(0.5)(py)(0.5)]center dot 52DMF center dot EtOH}(n) (3) and [Zn(L)(HNMe2)](n) (4). With Pb(NO3)(2) the ligand affords two polymers, {[Pb-2(L)(1.5)(O)(0.5)]center dot EtOH center dot 2H(2)O}(n) (5) and {[Pb-3(L)(3)(H2O)]center dot 6H(2)O}(n) (6). All of these compounds have been characterized by single crystal X-ray diffraction, infrared spectroscopy, thermogravimetry, elemental analysis, and powder X-ray diffraction measurements. Topological anlayses reveal that complex 2 is a 6-connected pcu net, while complexes 3 and 4 are simplified as a 4-connected sql net. In the case of complexes 1 and 6, one-dimensional rod-shaped metal carboxylate based secondary building units have been obtained. However, an uncommon structure and topology have been obtained in complex 5. Surprisingly, such type of parallel ladder-like packing is not explored much in coordination polymers. Solid-state photoluminescence studies have been carried out for all of the complexes upon excitation at 347 nm at room temperature.