Novel polyimide containing 1,10-phenanthroline and its europium(III) complex: synthesis, characterization, and luminescence properties

A novel aromatic diamine substituted with a 1,10-phenanthroline group in the side chain, N-(1,10-phenanthroline-5-yl)-3,5-diaminobenzamide, was synthesized and used to prepare polyimide via polycondensation with 4,4′-(hexafluoroisopropylidene)diphthalic anhydride. Subsequently, the europium(III) coordination polyimide was prepared using the polyimide as a macromolecular ligand and 2-thenoyltrifluoroacetone as a co-ligand. Their structures were systematically characterized by mass spectroscopies, Fourier transform infrared spectroscopy, 1H nuclear magnetic resonance, elemental analysis, and inductively coupled plasma. The obtained polyimide and europium(III) coordination polyimide exhibit excellent thermal stability and solubility in many polar aprotic solvents. The europium(III) coordination polyimide was demonstrated to emit strong characteristic fluorescence emission of europium(III) at 615 nm, showing promising potential in optical display devices.