Syntheses,Characterization And Reactivity Of Metal Complexes With Polydentate Amine N-heterocyclic Carbene Ligands

Since the N-heterocyclic carbene(NHCs)was firstly isolated in 1991,this kind of ligands with strong ?-donating ability have attracted much attention.NHC ligands can form stable complexes with a variety of metal and non-metal elements,which have found many applications in metal-organic catalysis,organocatalysis,luminescence and medicine.There are various types of NHC-containing ligands,including monodentate,bidentate and polydentate ones.NHC unit can form bidentate and polydentate functionalized NHC ligands with other donors such as nitrogen,oxygen,sulfur and phosphorous atoms.The most of nitrogen-functionalized NHC ligands contains unsaturated amines such as pyridine groups.In contrast,those with saturated amine have been relatively less studied.In general,NHCs can remain stable under normal circumstances.However,recent years have witnessed an increasing number of the reported examples on the novel reactions involved in the NHC unit including hydrolytic ring-opening and ring expansion.The research of this Dissertation focuses on the synthesis of several precursors of polydentate amine N-heterocyclic carbene ligands,macrocyclic amine N-heterocyclic carbene ligands and nine new metal complexes of polydentate amine N-heterocyclic carbene complexes.An interesting ring-opening reaction has been observed.It mainly includes the following three aspects:1)Several precursors of polydentate amine N-heterocyclic carbene ligands and macrocyclic amine N-heterocyclic carbene ligands were synthesized using multi-step methods including protection,deprotection,and ion exchange.These ligands were characterized by NMR,ESI-MS and elemental analysis.2)Nine nickel,palladium,and iridium complexes with the pentadentate amineN-heterocyclic carbene ligands have been synthesized by deprotonation with weak bases and transmetalation of silver complex.Necessary characterization of the complexes were performed by NMR,elemental analysis,ESI-MS and X-ray single crystal diffraction.3)A novel ring-opening reaction of NHCs has been discovered.The mechanism of the ring-opening reaction was studied and a possible reaction mechanism was proposed.