Organo Chalcogenone-Triggered Luminescent Copper(I) Clusters for Light Emitting Applications

Abstract

A novel organo sulfur and selenium-controlled emission behavior in discrete copper(I) clusters has been demonstrated for the first time. The pentanuclear [Cu 5 Br 5 (L 1 ) 2 ] (1), trinuclear [Cu 3 Br 3 (L 2 ) 2 ] (2), dinuclear [Cu 2 I 2 (L 1 ) 2 ] (3), and tetranuclear [Cu 4 I 4 (L 2 ) 2 CH 3 CN] (4) copper(I) discrete clusters have been synthesized from the reaction between L 1chelating ligands and corresponding copper(I) halide salts. These new clusters have been characterized by FT-IR, UV−visible, thermogravimetric analysis, and fluorescence spectroscopy techniques. Single-crystal X-ray diffraction studies reveal that 1−4 consists of abundant d 10 − d 10 interactions. The structural and bonding features of clusters have been investigated using density functional theory calculations. Notably, the L 2 -ligated 2 and 4 are poorly emissive, while L 1ligated 1 and 3 showed strong emission in the orange and green regions, respectively. The time-dependent density functional theory natural transition orbital calculations of 1 and 3 reveal the nature of the transitions contributed by 3 MLCT/ 3 LLCT/ 3 ILCT. Photoluminescence quantum yields of 1 and 3 are 19 and 11%, with average lifetimes of 21.55 and 6.57 μs, respectively. 1 and 3 were coated on prototype LED bulbs for light-emitting performance.