Synthesis, structure, and photophysics of copper(i) triphenylphosphine complexes with functionalized 3-(2'-pyrimidinyl)-1,2,4-triazole ligands.

A series of new mononuclear and dinuclear copper(i) triphenylphosphine complexes with functionalized 3-(2'-pyrimidinyl)-1,2,4-triazole ligands have been synthesized and characterized, in which functionalized 3-(2'-pyrimidinyl)-1,2,4-triazole adopts neutral mono- and bis-chelating coordination modes and a mono-anionic bis-chelating binding manner due to the 1,2,4-triazolyl-NH deprotonation. All these Cu(i) complexes display a relatively weak low-energy absorption in a CHCl solution, ascribed to the charge-transfer transitions with appreciable MLCT character, as suggested by TD-DFT analyses. These Cu(i) complexes are all emissive in solution and in the solid state at ambient temperature, and their luminescence properties can be well modulated via the addition of the second {Cu(PPh)} unit and modification of 3-(2'-pyrimidinyl)-1,2,4-triazole involving the N-H deprotonation and the substituent variation of the 1,2,4-triazolyl ring.