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

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 1 [ L 1 = 1-isopropyl-3-(pyridin-2-yl)-imidazol-2-thione] or L 2 [ L 2 = 1-isopropyl-3-(pyridin-2-yl)-imidazol-2-selone] chelating 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 1 -ligated 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.