Synthesis Of Half-Sandwich Yttrium Complexes Supported By Amidinate Ligands And Their Catalytic Behavior For Polar Vinyl Monomers

In this paper, a series of momo(amidinate) half-sandwich yttrium complexes were synthesized by two synthetic strategies. These complexes were characterized by nuclear magnetic resonance spectroscopy and some of them were characterized by single crystal X-ray diffraction. We have used them as catalysts for the polymerization of polar vinyl monomers.1. The target products were prepared by insertion reaction between carbodiimide and half-swandwich yttrium complexes.(n5:Ti1-C5Me4SiMe2C6H4)Y[(iW)2CCH2SiMe3](THF) and (C5Me4SiMe3)Y[NRiC(CH2SiMe3)NR2](CH2SiMe3)(Ri=R2=/Pr; Rx=Et, R2=’Bu; Ri=R2=Cy; Ri=R2=’Bu) were synthesized by this strategy. Single-crystal structure of (Y|5:r|1-CsMe4Si Me2C6H4)Y[(1PrN)2CCH2SiMe3](THF) revealed that the complex was linked half-sandwich yttrium complex supported by amidinate ligand.2. The other target products were prepared by acid-base reaction between cyclopentadiene and mono(amidinate) yttrium complexes.(C5H5)Y[RC(N-2,6-1Pr2C6H3)2](CH2SiMe3)(THF)(R=Ph, CH2SiMe3) were synthesized by mis strategy. And single-crystal structures were got about the two complexes.3. The series of complexes had highly activity for the polymerizations of methyl methacrylate (MMA), tert-butyl acrylate (’BA), dimethyl acryamide (DMAA), diphenyl acryamide (DPAA),2-vinylpyridine (2VP), which could get syndio-rich PMMA (rr=49.3%-80.7%).4. The polymerization of MMA was living polymerization in toluene at room temperature, catalyzed by complex (C5H5)Y[Me3SiCH2C(N-2,6-/Pr2C6H3)2](CH2SiMe3)(THF). And the complex could catalyze copolymerization of methyl methacrylate and ally methacrylate.