Synthesis And Properties Study Of Cu(?) Complexes With Novel Benzimidazole,Triazole Ligands

In this paper,four new benzimidazolidine phosphine ligands(L1-L4)and two new triazole ligands(L5-L6)were designed and synthesized,and fifteen new mononuclear and binuclear copper(?)complexes were prepared by the reaction of these ligands with different cuprous salts.The light-emitting properties of the complexes can be effectively controlled by introducing different substituents on the N^P benzimidazole ligands,consequently,the emissions from blue to yellow were realized.The contents are summarized as follows.(1)Two series(?-1??-4,?-1??-4)mononuclear Cu(I)complexes were obtained by the reaction of(L1?L4)and triphenylphosphine,4,5bisdiphenylphosphine-9,9-dimethylxanthene with[Cu(CH3CN)4]BF4.Besides,L1 reacts with CuI to obtain I-5,and L2 and triphenylphosphine react with CuCl to obtain I-6.All the compounds are characterized by1H NMR,13P NMR and elemental analysis.The structures of the complexes were determined by single-crystal X-ray diffraction.All the mononuclear copper(?)complexes adopted twisted tetrahedral configuration.By changing the substituents of L and auxiliary ligands,copper(?)complexes in the solid state display efficient emissions ranging from 488 to 577 nm.The quantum yields of these complexes are up to 20%?56%,the emission life times are about 6.4?55 ?s.The theory(TD-DFT)calculation was performed to elucidate the characteristic of absorption in the long wave region of the complex.It was found that electron transitions in the long wave length mainly attributed to the of MLCT and LL'LCT transitions.The emission spectra of complexes ?-3,?-4 and ?-1??-4 at 77 K are red-shifted relative to that at 293 K,and the calculated ?E(S1-T1)are all less than 1000 cm-1,which suggests that the emissions of these complexes at 293 K may attribute to thermal activation delay fluorescence.(2)It was found that the complexes ?-2-?-4 and ?-1,?-3 and ?-5 all have reversible mechanical coloration properties.In order to further explore the optical properties of these complexes.the complexes before and after mechanical grinding and after methanol fumigation fluorescence and XRD are carefully characterized by luminescent spectrs and XRD.(3)By the reaction of[Cu(CH3CN)4]BF4 with triazole phosphine ligands and auxiliary ligands,two dinuclear complexes with six-membered chelating ring and two mononuclear were obtained.The complexes all adopt deformed tetrahedral coordination geometries around copper(?)centers.These complexes in the solid state display superior emissions ranging from 493-557 nm,with quantum efficiency is up to 86.85%for complexes ?-1 with blue emission.Moreover,the emission spectrum of?-1 at 77 K was red-shifted 6 nm relative to that at 293 K,?E(S1-T1)is less than 1000 cm-1,indicating that the complexe may be an excellent blue emitting heat activation delay fluorescence material.The theoretical analysis shows that MLCT and L'LCT are the main transition modes of HOMO to LUMO.