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Unique Organic Crystal Skeleton Based on N‐Phenyl‐Carbazole Derivatives with Adjustable Room Temperature Phosphorescence and Highly Stable Inclusion Ability to Dichloromethane

Year: 2024

Type: article

Abstract: Monosubstituted 9‐(2‐bromophenyl)‐carbazole ( 1Br1CZ ) and disubstituted 9,9′‐(2,4‐dibromo‐1,3‐phenylene) bis(9H‐carbazole) ( 2Br2CZ ) are synthesized by introducing bromine into ortho‐phenyl position of 9‐phenyl‐carbazole ( PhCZ ). The decomposition temperature with 5% mass loss and melting point of 2Br2CZ crystal are 360 and 230 °C. The highest occupied molecular orbital energy level of PhCZ is the highest, and that of 2Br2CZ is the lowest. The crystals of PhCZ, 1Br1CZ , and 2Br2CZ are monoclinic, orthorhombic, and triclinic system, which exhibit room temperature phosphorescence with lifetimes of 171.81, 37.15, and 28.77 ms, and their corresponding phosphorescence quantum yields are 0.83%, 0.16%, and 4.58%. It theoretically reveals that six triplet energy levels (T 1 ‐T 6 ) exist under S 1 in 2Br2CZ crystal, and the spin orbit coupling constants between S 1 and T n in 2Br2CZ are also greater than those in PhCZ and 1Br1CZ , which promotes the intersystem crossing. Meanwhile, through crystal structure and Hirshfeld surface analysis, the torsion angles between the carbazole unit of 2Br2CZ and the central phenyl group reached 85.28°. The 2Br2CZ crystal exhibits the richest intermolecular interactions. A cavity of 4.498 Å is formed within the crystal skeleton of 2Br2CZ , which can precisely fixe dichloromethane with a record‐high desorption temperature over 145 °C.

Source: Small

DOI: 10.1002/smll.202404753

Authors: Xudong Liu, Hongji Jiang

Institutions: Nanjing University of Posts and Telecommunications, Fudan University, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology

Language: English

Topic: Luminescence and Fluorescent Materials

Subfield: Materials Chemistry

Field: Materials Science

Domain: Physical Sciences

Open Access status: bronze