Synthesis, Structural Characterization, And Properties Of Nickel, Silver And Gold Complexes Supported By N-Heterocyclic Carbenes

Recently,N-heterocylic carbenes(NHCs) have become an important class of ligands in organometallic chemistry and catalysis due to their excellentσ-donor properties,ease of synthesis,and variable steric bulk.They have been found tremendous application in the field of catalysis,new type of luminescent material, antibacterial and liquid crystal material.We have synthesized a series of air-stable nickel,gold and silver NHCs complexes via reactions of corresponding imidazolium salts with Ag₂O and transmetallations.This dissertation mainly includes two parts:In part one,but-2-yne-1,4-diyl linked bis-NHC-silver complexes have been prepared via the simple deprotonation reactions of imidazolium salts with Ag₂O. Then they were treated with Ni(PPh₃)₂Cl₂,and the CC'C pincer-like nickel complexes were synthesized through carbene transfer reactions.X-ray diffraction studies show that the distorted square-planar nickel(â…¡) complexes are supported by anionic terdentate ligands with two imidazolylidenes and one vinyl carbon donor originated from chloronickelation of the triple bond.Further studies suggest that the nickel complexes are excellent in catalyzing Kumada-Corriu coupling reactions of aryl chlorides even at room temperature.In part two,we have synthesized mixed-multinuclear silver- and gold-NHCs complexes supported by but-2-yne-1,4-diyl linked NHCs and pyridine functional group NHCs.Their structures were characterized by X-ray crystallography. Luminescent properties are investigated,and these silver- and gold-NHCs copmlexes exhibit emission band in between 410-460 nm.The cell cytotoxicity are also studied,and the toxicity order is consistent with the silver content in these complexes.These datas may provide useful clues for the design of coinage metal anti-tumor drugs.