Synthesis, crystal structure and performance study of cadmium(II) complex with 1,10-phenanthroline and 2-methyl-3-hydroxyquinoline-4-carboxylate anion

The present work employs a hydrothermal method to synthesize a novel Cd(II) inorganic-organic hybrid luminescent complex [Cd(phen)2Cl(H2O)]L·3H2O (L = 2-methyl-3-hydroxyquinoline-4-carboxylate anion, phen = 1,10-phenanthroline). The crystallographic analysis indicates that Cd(II) center exhibits a distorted octahedral coordination geometry, where two phen ligands form a bidentate chelate, while the deprotonated 2-methyl-3-hydroxyquinoline-4-carboxylate anion (L⁻) acts as a charge-balancing lattice anion. The solid-state UV-Vis diffuse reflectance spectroscopy (DRS) reveals an optical band gap of 4.69 eV (wide-gap semiconductor). Upon excitation at 385 nm, the complex exhibits blue-green fluorescence with an emission peak at 456 nm (CIE: 0.2247, 0.2545), indicating its potential as a blue-green emitting material. Thermogravimetric analysis (TGA) shows a three-step decomposition process, suggesting good thermal stability. The work offers a new structural paradigm for Cd(II)-based blue-green emitters.