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

A rigid linear ligand incorporating a carboxylic acid group at either end, p -terphenyl-4,4″-dicarboxylic acid, 2′,5′-dimethyl ( H 2 L ) 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 ]·8EtOH·4DMF} n ( 1 ), {[Zn(L)(bpmp) 0.5 ]·EtOH·1/2DMF} n ( 2 ), {[(Zn) 0.5 (L) 0.5 (py) 0.5 ]·5/2DMF·EtOH} n ( 3 ), and [Zn(L)(HNMe 2 )] n ( 4 ). With Pb(NO 3 ) 2 the ligand affords two polymers, {[Pb 2 (L) 1.5 (O) 0.5 ]·EtOH·2H 2 O} n ( 5 ) and {[Pb 3 (L) 3 (H 2 O)]·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 analyses 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.