학술논문
Closo- or Nido-Carborane Diphosphane as Responsible for Strong Thermochromism or Time Activated Delayed Fluorescence (TADF) in [Cu(N^N)(P^P)]0/+
Document Type
Article
Source
Inorganic Chemistry; December 2021, Vol. 60 Issue: 23 p18521-18528, 8p
Subject
Language
ISSN
00201669; 1520510X
Abstract
Ortho-closoor ortho-nido-carborane-diphosphanes have been selected to prepare the heteroleptic cationic or neutral [Cu(N^N){(PPh2)2C2B10H10}]PF6(1) and [Cu(N^N){(PPh2)2C2B9H10}] (2) [N^N = 2-(4-thiazolyl)benzimidazole], respectively. Complexes 1and 2display very different emissive behavior. Neutral complex 2exhibits TADF (time activated delayed fluorescence) which has been studied both as powder and PMMA composite with similar ΔE(S1– T1), τ(T1), and τ(S1) in both phases. Cationic complex 1displays a much lower quantum yield than 2and does not show TADF, but it exhibits a significant thermochromic luminescence, and its emission is very dependent on the medium. Theoretical studies show that metal–ligand (M–diphosphane) to ligand (L′, diimine) transitions, MLL′CT, are responsible of the transitions which originate the emissive properties, but with very different contribution of the copper center, carborane cluster, and diphosphane phenyl rings for 1and 2.