| Design and develop novel metal complexes to create novel polymerization catalysts play crucial role in the field of organometallic chemistry and polymeric chemistry. The steric and electronic configuration around the center metals has profound effect on the polymerization activity and the stereo- and regio-selectivity of the resulting polymers. In this research, employing amidinate ancillary ligands, a series of aluminum methyl complexes were prepared by alkane elimination reaction, and a large spectrum of rare earth metal amide complexes were synthesized by metathesis reaction. These complexes were characterized by elemental analysis, NMR, FT-IR. Some of these complexes were subjected to single crystal structural determination. It was found that amidinate aluminum methyl complexes could initiate the ring-opening polymerization ofε-caprolactone, and bis(amidinate)ligated rare earth metal amide complexes were active towards the ring-opning polymerization of L-lactide.1.A series of mono(amidinate) metal alumium bis(methyl) complexes and bridged-amidinate-ligated metal alumium tetra(methyl) complexes [Me2Al[(N-2,6-iPr2C6H3)2C]C6H4[C(N-2,6-iPr2C6H3)2]AlMe2] (1),[Me2Al[(N-2,6-Me2C6H3)2C]C6H4[C(N-2,6-Me2C6H3)2]AlMe2] (2),[Me2Al[(N-2,6-iPr2C6H3)2C]Cy[C(N-2,6-iPr2C6H3)2]AlMe2] (3),[Me2Al[(N-2,6-Me2C6H3)2C]Cy[C(N-2,6-Me2C6H3)2]AlMe2] (4),[PhC(N-2,6-iPr2C6H3)2]AlMe2 (5),[PhC(N-2,6-Me2C6H3)2]AlMe2 (6),[CyC(N-2,6-iPr2C6H3)2]AlMe2 (7) and [CyC(N-2,6-Me2C6H3)2]AlMe2 (8) were synthesized by alkane elimination reaction. These complexes were characterized by elemental analysis, IR spectroscopy, 1H NMR spectroscopy and 13C NMR spectroscopy. X-ray diffraction of complex 1, 3, 5 and 7 revealed that each aluminum is surrounded by one amidinate lingand and two methyl to display a distorted tetrahedron. These complexes showed activity towardsε-caprolactone polymerization.2.Bis(amidinate) rare earth metal amide complexes [PhC(N-2,6-Me2C6H3)2]2YN(SiMe3)2 (9),[PhC(N-2,6-Me2C6H3)2]2NdN(SiMe3)2 (10),[CyC(N-2,6-Me2C6H3)2]2YN(SiMe3)2 (11) and [CyC(N-2,6-Me2C6H3)2]2NdN(SiMe3)2 (12) were synthesized in high yields by one-pot salt metathesis reaction of anhydrous LnCl3, amidinate lithium salt [RC(N-2,6-Me2C6H3)2]Li [R = iPr, Me], and NaN(SiMe3)2 in THF at room temperature. These complexes were characterized by elemental analysis, IR spectroscopy, 1H NMR spectroscopy and 13C NMR spectroscopy, Single crystal structural determination of complexes 9, 10 and 12 revealed that the central metals adopt distorted pyramidal geometry. These complexes showed activity towards L-lactide polymerization in the presence of isopropanol.3.Mono(amidinate) rare earth metal bis(amide) complexes [PhC(N-2,6-Me2C6H3)2]Y[N(SiMe3)2]2] (13),[CyC(N-2,6-Me2C6H3)2]Y[N(SiMe3)2]2] (14) and [CyC(N-2,6-Me2C6H3)2]Lu[N(SiMe3)2]2(μ-Cl)Li(THF)3] (15) were synthesized in high yields by one-pot salt metathesis reaction of anhydrous LnCl3, amidinate lithium salt [RC(N-2,6-Me2C6H3)2]Li [R = Ph, Cy] or [CyC(N-2,6-R2C6H3)2]Li [R = iPr, Me], and 2 equiv. of NaN(SiMe3)2 in THF at room temperature. These complexes were characterized by elemental analysis, IR spectroscopy, 1H NMR spectroscopy, 13C NMR spectroscopy and X-ray diffraction. Single crystal structural determination of complexes 13 and 14 revealed that the central metals adopt a four-coordinated distorted tetrahedron, complexes 15 revealed that the central metals adopt a five-coordinated distorted pyramidal geometry.
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