Trichromatic color tuning strategy for emission of heterometallic EuIII/TbIII coordination polymers with triazolyl-substituted 4-methyl-phenoxo ligand

Abstract

This study presents the microwave-assisted synthesis and characterization of a series of heterometallic coordination polymers (HMCPs) with a 4-methyl-2,6-di[(1H-1,2,4-triazol-1-yl)]phenoxo ligand with varying EuIII/TbIII ratios. Single crystal X-ray diffraction reveals a double-chain structure bridged by triazolyl groups. Powder X-ray diffraction confirms the isostructural nature of the synthesized HMCPs. The photophysical properties depend on lanthanide ion concentration and excitation wavelength, leading to a color shift from green to blue as the proportion of TbIII decreases and EuIII increases. White light generation is achieved in the 8/2 EuIII/TbIII HMCP (CIE: 0.293, 0.326) under 335 nm excitation. The study suggests energy transfer from TbIII to EuIII, but both experimental and theoretical calculations indicate that this transfer is orders of magnitude lower than the sensitization through ligand states.