Synthesis And Catalytic Properties Of Cobalt Complexes Supported By Trimethylphosphine Via C-H Bond Activation And Si-H Bond Activation

Phosphine ligands have a strong ability to stabilize transition metal complexes.In organometallic chemistry,people usually tune the structure and property in order to change the electron density of transition metal complex.Trimethylphosphine is such kind of ligand and utilized in building transition metal complexes because of its small steric hindence,strong coordination effect and unique spectroscopic characteristics.C-H bond exists widely in organic compounds.The cleavage of C-H bond and transformation to other functional group under certain conditions can be highly efficient and atomic economic in organic synthesis and shorten the procedure.Comparing to traditional methods the transition metal complexes have their own potential.The C-H bond in aldehyde group can be easily activated by TM complexes and undergo decarbonylation reaction subsequently.As a kind of special aldehydes,the C=O bond and C=C bond in ?,?-unsaturned aldehyde can be activated and interact with transition metal complexes.In recent years,various kinds of noble transition-metal complexes,such as ruthenium,rhodium,osmium,iridium and platinum have been used in activating C-H bond of aldehyde.However,research on cheap transition metal such as iron,cobalt and nickel are rare.Comparing to noble transition metal,cheap transition metal has advantages in price,toxicity,environmental friendship.In recent years,silyl transition metal complexes have also attracted much attention.The activation of Si-H bond by transition metal complexes is a significant method to synthesize such compounds.Focusing on silyl metal complexes will deepen the comprehension of the mechanism participated by transition metal.Among those studies the activation of Si-H bond in NSiN pincer ligand by transition metal complexes is a novel synthetic method.In this dissertation,our work contains three parts.First,we performed activation reactions of cinnamaldehyde derivatives with low-valent cobalt complexes supported by trimethylphosphine and obtained complex 1-3 with ?4 structure and complex 4-8 with ?2 structure.The structures of complex 1,2,3,4 and 8 were confirmed by single crystal X-ray diffraction.In the second part we synthesized silyl transition metal complex 9-10.The structure of complex 10 was confirmed by single crystal X-ray diffraction.At last hydrosilation reaction of phenylaldehyde with trimethoxylsilane catalyzed by complex 10 was studied.However the conversion was not very good and the condition need further exploring.