Synthesis And Characterization Of Rare-Earth Pyrazolato And1,2,4-Triazolato Complexes

After CMOS technology comes into sub-45nm, high-K gate dielectric will become the promisingcandidate of SiO2to release the unacceptable and huge gate leakage current. Recently, rare earthoxides have received much focus, because they are the most promising high-K material. The key toachieve high quality rare earth oxide thin films is atomic layer deposition （ALD） technology. However,in order to design suitable precursors for ALD, rare earth chemists still have a considerable problemto address: the large radius of the lanthanide ions, and consequent requirement for high coordinationnumbers to satisfy steric demands. In this paper, we designed and synthesized pyrazolato and1,2,4-triazolato lanthanide complexes. The steric demands of these two series of complexes could beadjusted by the size of substituent groups. This thesis consists of the following three parts:Part1: synthesis of trisamido lanthanide complexes and lanthanide borohydrides.The synthesis of La[N（SiMe₃）₂]₃was optimized firstly, through improving the method of activationof LaCl₃. The ultrasonic activation method of LaCl₃could shorten the activation time and improve theyield. The salt metathesis reaction of La（BH₄）₃（THF）₃and NaN（SiMe₃）₂was also studied.Part2: synthesis and characterization of pyrazolato lanthanide complexes:Heteroleptic pyrazolato lanthanide complexes （R₂Pz）_nL_n[N（SiMe₃）₂]₃-n（Ln=La, Gd; R=Me, t-Bu,Ph; Pz=C₃HN₂; n=1,2,3） were synthesized by protolysis of Ln[N（SiMe₃）₂]₃with pyrazole. Thecomplexes obtained were characterized by1H NMR,13C NMR, elemental analysis and X-ray singlecrystal analysis, respectively. The ligand redistribution of these complexes was also discussed.Part3: synthesis and characterization of1,2,4-triazolato lanthanide complexes:Homoleptic1,2,4-triazolato lanthanide complexes （R2Tz）₃Ln（THF）x（Ln=La, Gd; R=Me, n-Pr,n-Bu, Ph; Tz=C₂N₃; x=0,3） were synthesized by protolysis of Ln[N（SiMe₃）₂]₃with1,2,4-triazole.The complexes obtained were characterized by1H NMR,13C NMR, elemental analysis and X-raysingle crystal analysis, respectively. The influence of intramolecular edge-to-face C-H···π interactionson coordination geometries and the bond length of La-N bonding were also investigated.