Synthesis And Catalytic Properties Of Base Metal Complexes Supported By Trimethylphosphine And N-Heterocyclic Silylenes

The kind of transition metal hydrides is a very important component in organometallic complexes.In the field of catalysis,it combines many advantages,such as mild reaction conditions,high yields and high substrate selectivity to become a powerful weapon for catalytic activation of small molecule compounds.In recent years,chemists had discovered that the structure and characteristics of metal hydrides had a crucial influence on their catalytic activity.If we can understand the effect of the steric hindrance and electrical properties of the metal hydrides on the catalytic efficiency,it will be more beneficial to the selection of the optimal catalyst in the catalytic reaction.As an analogue of carbene and organophosphorus ligand,silylene has stronger?-donating/?-accepting and unique steric hindrance,which made some low-cost silylene is better for organometallic complexes than the general carbene and organophosphorus ligand.At present,the report of base metal hydrides coordinated by silylene was very limited and there are few studies on its application in the field of catalysis.So the research on the synthesis and catalytic properties of silylene-coordinated metal hydrides is very considerable.Our group has made many reports on the synthesis and properties of[S,PPh2],[Se,PPh2]chelated metal complexes.On this basis,the main research content of this paper is to report the effect of the catalytic efficiency of phosphorus-chalcogen chelated iron hydrides and compare the differences in structure and properties between the silylene coordinated metal complexes and organophosphorus ligand coordinated metal complexes.In addition,the application of the silylene coordinated metal complex in catalytic reaction was also explored.The specific research content is as follows:1.Novel[O,PiPr2]chelated iron hydrides 4,5 and[S,PiPr2]chelated Fe complex 8 were synthesized.We compared the electrical properties and steric hindrance of[O,P],[S,P]and[Se,P]chelated iron hydrides by changing coordinated atoms,phosphine ligands and substituent groups on the benzene ring to affect the catalytic reaction of dehydration of primary amides to nitriles.2.Complex 5 reacted with chlorosilylene to synthesize novel silylene-coordinated Fe complexes 10 and 11.The effect of reaction solvents were studied,and the possible mechanism of the reaction was proposed.3.Novel[O,PiPr2]double-chelated Co and Ni complexes 12 and 13 were synthesized.The application of two metal complexes in the hydrosilylation of olefins was studied.4.The silylene-coordinated iron hydrides 14 was used in the catalytic reaction of hydrosilylation of aldehydes and ketones.Then we explored the advantages of silylene-coordinated metal complexes in this catalytic reduction reaction compared with traditional phosphorus ligand coordinated metal complexes.