A New CuII Coordination Polymer: Structural Elucidation, EPR and Sensing Studies for Detection of Volatile Organic Solvents

The copper derivative [Cu(H-stp)(bipy)(H2O)2]n·H2O (1) is afforded by combining flexible 2-sulfoterephthalic acid monosodium salt [Na(H2stp)] and divalent copper nitrate in presence of the N-donor ancillary co-ligand, 4,4’-bipyridyl. As a result of the potential coordination modes of carboxylate oxygens from the stp ligand and the bipy co-ligand, a one dimensional chain
is formed as evident by single-crystal X-ray diffraction technique. Solvent exchange studies reveals that compound 1 is able
to sense various small polar volatile organic compounds (VOCs) and acts as a good capacitative sensor under ambient conditions. An increase of the temperature from 100 to 298 K on EPR measurement causes a variation of the SOMO composition and a change of the spectrum from an ’inverse’ to a ‘rhombic’ one. On temperature dependent magnetic study, the cMT value
of compound 1 is 6.86 cm3 K mol-1 at 5 K which decreases up to 8.81 cm3 K mol-1 at 300 K.