Long-lived phosphorescence emission of self-penetrating MOF based on 1,4-bis(imidazole-1-ylmethyl)benzene: Syntheses, structure and photoelectron performance

One new binuclear Cd(II) based 3D metal-organic framework (MOF) [Cd(HBTC)(BIMB)] (1) (H3BTC ​= ​1,2,4-benzenetricarboxylic acid, BIMB ​= ​1,4-bis(imidazole-1-ylmethyl)benzene) was synthesized by the mixture of HBTC and BIMB ligands. X-ray single-crystal diffraction analysis indicates that the title MOF exhibits a 3D self-penetrating structure with the alternate arrangement of HBTC and BIMB ligands in spatial. Time-resolved measurements reveal that 1 exhibits prolonged phosphorescence lifetime more than 10 times in comparison with the pristine BIMB phosphor ligand. Theoretical calculations indicate that the HOMO and LUMO are completely separated and located on the BIMB and HBTC ligands, respectively, facilitating the generation of triplet state for long-lived phosphorescence emission. In addition, the photoelectron responds performance of 1 have also been studied.