Synthesis,Characteritation And Properties Of N-heterocyclic Carbene Copper Complexes

On the one hand,due to good optical properties,richness in resources and cheapness,copper(I)complexes has been widespread concerned gradually.They even can replace rare-earth metal complexes which have excellent luminescent properties.On the other hand,the N-heterocyclic carbene ligand has similar properties with the phosphine ligands,but it has more powerful ability to donate electrons,and is more likely to be modified,whcih makes it more and more beloved.In this paper,we designed and synthesised some Cu(I)-NHC complexes,and their photophysical properties were studied.The specific contents are as follows:1?We treated 2-(imidazol-1yl)-pyridine as the base,and synthesized a series of imidazolium salts.Then coppoer powder and bis(2-diphenylphosphinophenyl)ether(POP)were used to react with these imidazolium salts.The corresponding Cu(I)complexes were obtained,and they was noted as A1,A2,A3,A4.As a result,the UV-visible absorption spectras of these complexes have little difference.Maybe,it was because that the changed substituent groups couldn't make differences in the spectras.And this phenomenon was consistent with our theoretical results.Their emission located in the green light region.The fluorescence quantum yield of P1 and P2 was 38.3% and 43%,and they were good yellow-green light-emitting materials.2?We synthesized a series of benzimidazolium salt on the basic of1-(2-pyridyl)-benzimidazole.And we used the same way to obtain their corresponding Cu(I)-NHC complexes which were recorded as P5,P6,P7,P8.The substituent groups had no effect on their UV-visible absorption spectras,which were supported by theoretical calculations.Compared with the first series,their emission had a red shift,which was resuled form the expansion of the conjugated struceure.The fluorescence efficiences of P6 and P7 were 34.9% and 41.0%,and they could be used as good optical material of yellow light.3?We changed the base to 1-picolyl benzimidazole,and got a new series of compounds which were named P9,P10,P11,P12.Similarly,there was little difference among their UV-visible absorption spectras.A methylene was put betweentwo aromatic rings,and cause an emitting blue-shift of this series compared with the former two series.P9 and P10 had good quantum yields(35.2% and 38.3%),and they emitted at 513 nm and 511 nm,respectively.These two complexes were good blue-green light-emitting materials.