•The titanium and zirconium complexes based on thioether substituted β-carbonylenamine were synthesized.•X-ray analysis proved the molecular structure of the corresponding titanium and zirconium complexes.•The titanium complexes could promote styrene syndiotactic polymerization smoothly at 90 °C for at least 4 h.•The introduction of a CF3-group results in an improved catalytic activity in the styrene polymerization at 90 °C.The titanium and zirconium complexes based on thioether substituted β-carbonylenamine were prepared and characterized. In the presence of MMAO, the titanium complexes showed good activity in syndiospecific styrene polymerization with high syndioselectivity, and performed good thermal stability. Electron withdrawing group on ligands is beneficial to the styrene polymerization. [1,3-diphenyl-3-(2-(isopropylthio)ethylimino)prop-1-en-1-olate]2ZrCl2(IV) could also polymerize styrene to give syndiotactic polymer, however in low activity and with low syndioselectivity.The titanium and zirconium complexes based on thioether substituted β-carbonylenamine were prepared and characterized. In the presence of MMAO, the titanium complexes showed good activity in syndiospecific styrene polymerization with high syndioselectivity, and performed good thermal stability. Electron withdrawing group on ligands is beneficial to the styrene polymerization.

•(ArO)TiR3 (X = NMe2, Cl, CH2Ph) complexes for highly syndiospecific styrene polymerization were synthesized.•ArOTiX3 could promote the styrene syndiotactic polymerization smoothly at high temperature (110–130 °C) for at least 4 h.•(2-(Tert-butyl)-6-dimethylphenoxy)titanium(IV) trichlorides gave the highest activity (1.95 × 105 g sPS/mol(Ti) h) in the styrene polymerization at 110 °C.•It provides a potential way to develop thermal stable styrene syndiospecific polymerization catalyst.A kind of (ArO)TiR3 (ArO = 2,6-(R′)2-4-methylphenolate, R′ = Me, tBu, CH2SPh, CH2N(iPr)2, CH2NPh2) complexes was synthesized and characterized. X-ray analysis of 6a and 7 shows that neither CH2SPh (6a) nor CH2N(iPr)2 group (7) coordinates to titanium. Large bond angles C(Ar)-O(1)-Ti(1) angel (152.9(2)° in 6a and 175.33° in 7 indicate that the bond have partial sp-hybridized character. Upon treatment with modified methylaluminoxane (MMAO), the titanium complexes exhibit significant thermal stability, and prove useful as styrene syndiotactic polymerization catalysts. Comparisons between different complexes on the styrene polymerization were discussed. Steric instead of electronic properties at 2,6-positions of phenol affect the polymerization activity. (2-tert-Butyl)-4-methylphenoxytitanium(IV) chloride 5e was established the most efficient one. High activity (1.11 × 105 g sPS/mol(Ti) h) was achieved when styrene polymerization was carried out in the presence of 5e/MMAO at 130 °C for 2 h.Phenolate (ArO)TiR3 (ArO = 2,6-(R′)2-4-methylphenolate, R′ = Me, tBu, CH2SPh, CH2N(iPr)2, CH2NPh2) complexes were synthesized. The complexes prove useful to catalyze styrene syndiospecific polymerization and exhibit good thermostability in the presence of MMAO. High activity (105 g sPS/mol(Ti) h) are achieved when styrene polymerization is carried out at 130 °C for 2 h.

A series of titanium complexes bearing [ONX] tridentate ligands have been synthesized and characterized. The complexes containing sulfur or phosphine donors showed high activity in the copolymerization of ethylene with 9-decen-1-ol (up to 1.3 × 108 g polymer (mol Ti)−1 h–1) with an incorporation ratio of up to 8.8 mol %. Moreover, they have also shown excellent capability for copolymerization of ethylene with AlBui3 (or tert-butylchlorodimethylsilane) pretreated 4-penten-1-ol, ω-alkenoic acid, and ω-alkenoic ester, as well as unprotected tertiary amine.

Several new nickel complexes are prepared by the treatment of the stabilized ylide benzoylmethylenetri(2-alkoxylphenyl)phosphorane with Ni(cod)2 in the presence of PPh3. X-Ray diffraction studies reveal that a distorted square planar geometry around Ni(II) is adopted. Upon treatment with Ni(cod)2, the nickel complexes are sufficiently robust for ethylene polymerization. The existence of 2-alkoxyl-aryl substituents on phosphorus improves the catalytic activities. The highest activity (2.1 × 106 g mol−1 h−1) is achieved when tri(2-isopropoxy-phenyl)phosphorane is employed (5e), which is one order higher than the corresponding SHOP catalyst. NMR analysis shows that the polyethylene mainly contains terminal double bonds and is highly linear.

Several new nickel complexes are prepared by the treatment of the stabilized ylide benzoylmethylenetri(2-alkoxylphenyl)phosphorane with Ni(cod)2 in the presence of PPh3. X-Ray diffraction studies reveal that a distorted square planar geometry around Ni(II) is adopted. Upon treatment with Ni(cod)2, the nickel complexes are sufficiently robust for ethylene polymerization. The existence of 2-alkoxyl-aryl substituents on phosphorus improves the catalytic activities. The highest activity (2.1 × 106 g mol−1 h−1) is achieved when tri(2-isopropoxy-phenyl)phosphorane is employed (5e), which is one order higher than the corresponding SHOP catalyst. NMR analysis shows that the polyethylene mainly contains terminal double bonds and is highly linear.