Bromine heavy-atom induced persistent room temperature phosphorescence of [ZnBr2] based coordination polymer

• Published in: Journal of solid state chemistry Vol. 298; p. 122135
• Main Authors: Zhai, Zhi-Min, Yang, Xiao-Gang, Qin, Wen-Jing, Tian, Xu-Ke, Zhang, Ji-Rui
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 01-06-2021
• Subjects: Coordination polymers; Crystal structure; Photoelectron response; Room temperature phosphorescence; Coordination polymers; Photoelectron response; Room temperature phosphorescence; Crystal structure
• ISSN: 0022-4596; 1095-726X
• DOI: 10.1016/j.jssc.2021.122135

Molecule-based room temperature phosphorescence (RTP) materials have attracted considerable attention owing to their extensive applications in the optoelectronic and biological field. In this paper, two isostructural coordination polymers [Zn3(TIB)2X6] (X ​= ​Cl, 1-Cl; X ​= ​Br, 1-Br) have been synthesised and characterized by the assemble of triangular D-A-D ligand 1,3,5-tri(1H-imidazol-1-yl)benzene (TIB) and ZnX2 salts. The incorporation of halogen atoms play significant role in the formation of abundant C-H···X hydrogen-bonding interactions and dense structures, enable high thermal stability of the two complexes. 1-Br shows phosphorescence lifetime three order of magnitude longer than that of 1-Cl, and obviously phosphorescence emission recognized by naked eyes. The theory calculations reveal complete separation of molecular orbitals between halogen atoms and TIB ligand. Photoelectron response performance have also been studied. This work provides an efficient way to achieve long-last RTP by the incorporation of metal-bromide units in the coordination polymers.
Herein, two [ZnX2] based isostructural coordination polymers (X ​= ​Cl, 1-Cl; X ​= ​Br, 1-Br) have been reported. 1-Br shows obviously phosphorescence emission by naked eyes and lifetime three order of magnitude longer than that of 1-Cl. [Display omitted]
•Two [ZnX2] based isostructural MOFs (X ​= ​Cl, 1-Cl; X ​= ​Br, 1-Br) have been successfully synthesised.•1-Br shows long-lived phosphorescence lifetime three orders of magnitude longer than 1-Cl.•The long-last yellow-green emission can be directly observed by naked eyes after removing the light source.