Crystal structures, Hirshfeld surface analyses and optical properties of four new Cu(II)-based coordination polymers

Coordination polymers have been proven to be research hotspots for their fascinating structure and functional properties. In this work, four new Cu(II)-based CPs, namely [Cu(L)(H2O)]n (1), [Cu(L)(phen)(H2O)]·1.5H2O (2), {[Cu(L)(bimb)0.5]·H2O}n (3) and {[Cu(L)(dib)0.5(H2O)]·1.5H2O}n (4) [H2L=3-carboxy-1-(3′-carboxy-benzyl)-2-oxidopyridinium, 1,10-phenanthroline (phen), 1,4-bis-((1H-imidazol-1-yl)methyl)benzene (bimb) and 1,4-di(1H-imidazol-1-yl)butane (dib)], were synthesized under hydrothermal conditions. These four compounds show different structures defined by single-crystal X-ray diffraction. In addition, these compounds are characterized by powder X-ray diffraction (PXRD), infrared spectra (IR), elemental analyses, thermogravimetric analyses, Hirshfeld surface analyses and UV–vis absorption spectra.