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Four new binuclear aluminum chloride complexes {(1)AlCl}2 (5), {(2)AlCl}2 (6), {(3)AlCl}2 (7) and {(4)AlCl}2 (8) have been prepared in good yields by alkane elimination from the reaction of AlEt2Cl and chiral biaryl-based N2O ligands, (S)-2-(pyridine-2-ylmethylamino)-2′-hydroxy-1,1′-binaphthyl (1H2), (S)-5,5′,6,6′,7,7′,8,8′-octahydro-2-(pyrrol-2-methyleneamino)-2′-hydroxy-1,1′-binaphthyl (2H2), (S)-5,5′,6,6′,7,7′,8,8′-octahydro-2-(pyridine-2-ylmethylamino)-2′-hydroxy-1,1′-binaphthyl (3H2) and (S)-2-(pyrrol-2-methyleneamino)-2′-hydroxy-6,6′-dimethyl-1,1′-biphenyl (4H2), which are derived from (S)-2-amino-2′-hydroxy-1,1′-binaphthyl or (S)-2-amino-2′-hydroxy-6,6′-dimethyl-1,1′-biphenyl, respectively. Complexes 5–8 have been characterized by various spectroscopic techniques, elemental analyses, and X-ray diffraction analyses. The complexes 5–8 have a similar C2 quasi-symmetric ClN2AlO2AlN2Cl core structure, and they are active catalysts for the polymerization of rac-lactide in the presence of propylene oxide (PO), leading to the heterotactic-rich polylactides.

The new chiral NHC–iridium complex 3 has been prepared in CH3CN from the reaction between [Ir(COD)Cl]2, NaOAc, KI, and dibenzimidazolium salt 2 which is derived from (S)-2,2′-diamino-6,6′-dimethyl-1,1′-biphenyl. Complex 3 has been characterized by various spectroscopic techniques, elemental analyses, and X-ray diffraction analysis. It has a distorted-octahedral IrC2N2IH core structure, and shows good catalytic activity for the asymmetric hydrosilylation of arylmethyl ketones, leading to 1-arylethanol with moderate ee values.

A new chiral tetrameric zinc complex [(1)ZnEt]4 (2) has been readily prepared via alkane elimination between ZnEt2 and a chiral azetidine derivative, (2R,3R)-1-[(1S)-1-(4-methoxyphenyl)ethyl]-2-phenyl-3-hydroxyazetidine (1H). Complex 2 has been characterized by various spectroscopic techniques, elemental analyses, and X-ray diffraction analysis. Complex 2 has a cubane-like Zn4O4 core structure, and is an active catalyst for the polymerization of rac-lactide, leading to the heterotactic-rich polylactides.

Treatment of ThCl4(tmeda)2 with 3 equiv of [η5-1,3-(Me3C)2C5H3]K in toluene under reflux gives the tris-Cp chloride complex [η5-1,3-(Me3C)2C5H3]3ThCl (1) in 75% yield. The chlorine atom can be replaced by other groups via metathesis reactions. For example, reaction of 1 with an excess of KH in toluene under reflux affords the hydride complex [η5-1,3-(Me3C)2C5H3]3ThH (2) in 68% yield. Complexes 1 and 2 have been characterized by various spectroscopic techniques, elemental analyses, and X-ray diffraction analyses. Complex 2 is an active catalyst for the polymerization of rac-lactide, leading to the atactic polylactides with high molecular weights and narrow molecular weight distributions.

Five group 4 metal complexes (1)2Zr(NMe2)2 (5), (2)2Ti(NMe2)2 (6), (2)2Zr(NMe2)2 (7), (3)2Zr (8) and (4)2Ti(NMe2)2 (9) have been readily prepared from the reaction between M(NMe2)4 (M = Ti, Zr) and chiral binaphthyldiamine-based ligands, (R)-2,2′-bis(diphenylthiophosphoramino)-1,1′-binaphthyl (1H2), (R)-5,5′,6,6′,7,7′,8,8′-octahydro-2,2′-bis(diphenylthiophosphoramino)-1,1′-binaphthyl (2H2), (R)-5,5′,6,6′,7,7′,8,8′-octahydro-2,2′-bis(methanesulphonylamino)-1,1′-binaphthyl (3H2), and C1-symmetric ligand, (R)-2-(mesitylenesulphonylamino)-2′-(dimethylamino)-1,1′-binaphthyl (4H). All the complexes have been characterized by various spectroscopic techniques, elemental analyses and X-ray diffraction analyses. The zirconium amides are active catalysts for the asymmetric hydroamination/cyclization of aminoalkenes, affording cyclic amines in good yields with moderate ee (enantiomeric excess) values.

The chiral biaryl-based N4-ligands, (R)-5,5′,6,6′,7,7′,8,8′-octahydro-2,2′-bis(pyrrol-2-ylmethyleneamino)-1,1′-binaphthyl (1H2) and (S)-2,2′-bis(pyrrol-2-ylmethyleneamino)-6,6′-dimethyl-1,1′-biphenyl (2H2), can effectively stabilize the chiral rare earth metal chloride complexes such as 1-YCl(dme) (3) and 2-YCl(dme) (4), which offers important intermediates for the preparation of chiral rare earth catalysts containing the M–C or M–X (X = heteroatom) bonds. For example, treatment of 3 with half equiv of 1Na2 in THF gives the binuclear complex 1-Y(thf)-1-Y(thf)-1 (5) in 70% yield. These complexes have been characterized by various spectroscopic techniques, elemental analyses, and X-ray diffraction analyses. The complex 5 is an active catalyst for the ring-opening polymerization of rac-lactide, affording isotactic-rich polylactides.

Treatment of the chloride metallocene [η5-1,3-(Me3C)2C5H3]2ThCl2 or [η5-1,2,4-(Me3C)3C5H2]2ThCl2 with 2 equiv of PhCH2K in diethyl ether at room temperature gives, after recrystallization from a benzene solution, the benzyl metallocenes [η5-1,3-(Me3C)2C5H3]2Th(CH2Ph)2 (1) and [η5-1,2,4-(Me3C)3C5H2]2Th(CH2Ph)2 (2), respectively, in good yields. Complexes 1 and 2 have been characterized by various spectroscopic techniques, elemental analyses, and X-ray diffraction analyses. They are active catalysts for the polymerization of rac-lactide, leading to the atactic polylactides with high molecular weights and narrow molecular weight distributions.

Two new chiral organoyttrium amidate complexes 1 -Y[N(SiMe3)2]2 ( 3 ) and 2 -Y[N(SiMe3)2]2·C6H12 ( 4 ·C6H12) have been readily prepared in good yields by silylamine elimination reaction between Y[N(SiMe3)2]3 and chiral binaphthyl-based amidate ligands, (R)-2,2′-bis(mesitoylamino)-1,1′-binaphthyl (1) and (S)-2-(mesitoylamino)-2′-(dimethylamino)-1,1′-binaphthyl (2) , respectively. Complexes 2 and 3 have been characterized by various spectroscopic techniques, elemental analyses, and X-ray diffraction analyses. Complexes 3 and 4 are active catalysts for the polymerization of rac-lactide, leading to the isotactic-rich polylactides.