Heterometallic Clusters With Rare Earth Metal-Metal Bonds

Molecular clusters featuring metal-metal bonds have been fascinating scientists for decades because of their fundamental importance in the understanding of structure and bonding,catalysis,magnetism and the chemistry of metal surfaces.In the past few decades,studies on metal-metal bonds have mainly focused on d-block transition metals.This thesis mainly focuses on the synthesis and characterization of complexes containing rare earth(RE)metal-metal bonds,and also has made some preliminary attempts on other topics in the field of rare earth organometallic chemistry.In the first chapter,the examples of complexes containing RE-M bonds with various metals are summarized,and the synthesis methods and properties of the RE-M bonds are emphasized.Moreover,the progresses of RE-ligand multiple bonds and RE-promoted dinitrogen activation are briefly introduced.In the second chapter,a series of heterometallic clusters with RE-M bonds were synthesized by the reaction of Pd(PPh₃)₄ or[Rh Cl(COD)]₂ with RE complexes(RE=Ce,La and Nd)supported by N₄P₃ ligand.These clusters were characterized by X-ray single crystal diffraction,NMR,elemental analysis and XPS.We found that the reaction of triamidoamine type RE complexes with zero-valent Pd(PPh₃)₄ can generate heterometallic clusters containing multiple RE-Pd bonds.The triamidoamine type RE complex reacts with the monovalent[Rh Cl(COD)]₂ to obtain the Cl-bridged heterometallic clusters,which are then reduced by potassium graphite(KC₈)to obtain the heterometallic clusters containing multiple RE-Rh bonds.In the third chapter,we try to construct RE-N multiple bonds and RE-promoted dinitrogen activation.A series of diamine type Ce^?and Ce^?complexes were synthesized and thus the Ce-amine complexes were successfully isolated by amine elimination and salt elimination.However,try to synthesize the expected complex with Ce-N multiple bonds was unsuccessful.In addition,RE-promoted dinitrogen activation was attempted under reduction conditions.