Research Information System
Journal of Molecular Structure, vol.1334, 2025 (SCI-Expanded, Scopus)
Two Co(II)-coordination polymers, [Co3(µ-tbipH)2(µ4-tbip)2(pbisoix)]n (1) and {[Co3(µ-tbipH)2(µ4-tbip)2(µ-pbisoix)]·2H2O}n (2) (tbip and tbipH: deprotonated and mono deprotonated 5-tert-butyl isophthalate, pbisoix: 1,4-bis(2-isopropylimidazol-1ylmethyl)benzene), were hydrothermally prepared using different metal salts and characterized by various techniques. The coordination polymers (CPs) exhibited structural diversity depending on the rotation of imidazole arms of the pbisoix ligands. X-ray results revealed that Co2+ ions were coordinated by tbip and tbipH to generate [Co3(COO)6] units in both CPs. These units linked by tbip ligand to create a 1D structure in CP-1 and a 2D layer in CP-2. In 2, the pbisoix linkers acted as a bridging ligand, connecting the 2D layers and resulting in a 3D structure, whereas the pbisoix linkers displayed monodentate coordination in 1. The catalytic activities of the CPs were investigated for the cycloaddition of CO2 with epichlorohydrin (ECH) to form cyclic carbonates. The CPs showed high ECH conversion, with yields of 90.3 % and 60.0 %, respectively, into the cyclic carbonate (100 °C, 1.6 MPa, 2 h). The difference in the catalytic conversion yields between two CPs could be attributed to the presence of uncoordinated N atoms in the pbisoix linkers, which acted as Lewis basic sites, facilitating the efficient chemical fixation of CO2 to form cyclic carbonates.