Linear dicarboxylate based pyridyl appended cobalt(II) coordination polymers in search of opto-electronic properties

Two new coordination polymers (CPs) [Co(adc)(4-ppy)(H2O)2]n, (1) and [Co(adc)(4-bppy)(H2O)2]n, (2) (H2adc = acetylenedicarboxylic acid, 4-ppy = 4-phenylpyridine and 4-bppy = 4-(4-bromophenyl)pyridine) have been synthesized and characterized by various techniques including elemental analysis, infrared spectra, powder X-ray diffraction (PXRD), single crystal X-ray diffraction (SCXRD) technique patterns and thermogravimetric analysis (TGA). Both the compounds form one-dimensional (1D) chain-like structure constructed by linear dicarboxylate and pyridyl based organic linkers and show significant non-covalent interactions. Both the compounds exhibit electrical conductivity and reveal Schottky barrier diode behavior. However, compound 1 shows slightly better electrical conductivity (2.61×10-5 Sm-1) with respect to compound 2 (2.52× 10-6 Sm-1). The optical band gap of both compounds in the solid state have also been determined by experimental measurements and compared with the theoretical value obtained from DFT calculations.