Three Pyrazolyl Boron / Cyclopentadienyl (silicon Amino) Mixed-rare Earth Complexes

Tris(pyrazolyl)borate anion (Tp^*) ligands are currently attracting considerable attention due to their stable electronic geometry, facile steric modification, versatile bonding-mode, and their outstanding performance in conferring organometallic complexes higher reactivity and new reaction patterns. This thesis focus mainly on investigating on the synthesis and reactivity of lanthanide derivatives with the tris(3,5-dimethylpyrazolyl)borate ligand (Tp^Me2), wherein 27 new lanthanide complexes with the Tp^Me2 are synthesized and the structures of 26 compounds are determined through X-ray single crystal diffraction analysis. Moreover, several new reactivity patterns of tris(3,5-dimethylpyrazolyl)borate lanthanide complexes are established. This thesis is composed of three chapters.In Chapter 1, preface, the development of the synthesis and reactivity of lanthanide complexes containing the poly(pyrazolyl)borate ligands are introduced. Reaction chemistry of lanthanide(Ⅱ) complexes with tris(3,5-dimethylpyrazolyl)borate ligand is also described.In Chapter 2, We have developed an effective and versatile method to synthesis of Cp₂LnTp^Me2 and (Tp^Me2)CpLnCl(THF) complexes directly from Cp₃Ln, Cp₂LnCl, and CpLnCl₂ precursors. An unusual solvent-dependent reactivity pattern of Cp₂LnCl is observed. Furthermore, we find that the Cp ligands of Cp₂LnTp^Me2 are readily replaced step by step by other organic and inorganic ligands, such as pyrazolate, triazolate and 2-pyridylamino, via a protonation and thus demonstrate that these mixed Tp^Me2/Cp lanthanide complexes would be of great synthetic potential. During the investigation on the reactivity of complex Cp(Tp^Me2)Er[2-NC₅H₄NC(NHⁱPr)NⁱPr], a unusual double ligand-exchange product Cp(Tp^Me2)Er[2-NC₅H₄NC(NHⁱPr)NⁱPr] is obtained.In Chapter 3, we synthesized a series of bis(trimethylsilyl)amide lanthanide complexes with the tri(3,5-dimethylpyrazolyl)borate ligands from mono-Tp^Me2 lanthanides chlorides Tp^Me2LnCl₂, and found that three series of products can be obtained depending on the ratio of Tp^Me2LnCl₂ and KN(SiMe₃)₂, [(Tp^Me2)₂Er] [(N(SiMe₃)₂)₂Er(CH₂SiMe₂N(SiMe₃))], [(Tp^Me2)₂Er] [((Me₃Si)₂N)₃ErCl], [(Tp^Me2)₂Er] [((Me₃Si)₂N)₂Er₂Cl₂(μ-Cl)₂K] , Furthermore, a novel sterically induced C-H active -tion (γ-deprotonation) of lanthanide bis(trimethylsilyl)amide complexes has been achieved. We also realized their double C-H activation when excess of KN(SiMe₃)₂ was used.