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A new ortho-dimethylaminomethylphenyl-tetramethylcyclopentadienyl ligand C5Me4H-C6H4-o-CH2NMe2 (HL) and a series of rare-earth metal complexes bearing this ligand were synthesized. Of these complexes, two binuclear alkyl complexes [(C5Me4-C6H4-o-CH2N(Me)CH2-μ)Ln(CH2SiMe3)]2 (Ln = Sc (1a) and Y (1b)) were obtained from the alkane elimination reaction of the free ligand with Ln(CH2SiMe3)3(THF)2, followed by an intramolecular C–H activation process of a NMe group in the ligand with a CH2SiMe3 group, two binuclear dichloro complexes (C5Me4-C6H4-o-CH2NMe2)2Y2Cl4[LiCl(THF)2] (2a) and [(C5Me4-C6H4-o-CH2NMe2)LuCl(μ-Cl)]2 (2b) were synthesized by the reaction of anhydrous yttrium or lutetium trichloride with the lithium salt of the ligand LiL, and the binuclear bis(borohydrido) complexes [(C5Me4-C6H4-o-CH2NMe2)Ln(μ-BH4)BH4]2 (Ln = Sm (3a) and Nd (3b)) were synthesized by the reaction of Ln(BH4)3(THF)3 (Ln = Sm and Nd) with the lithium salt of the ligand. The molecular structures of all complexes 1a, 1b, 2a, 2b, 3a and 3b were determined by single-crystal X-ray crystallography. Upon activation with AlR3/Ph3CB(C6F5)4, MAO or MMAO, the binuclear alkyl complexes 1a and 1b show good catalytic activity for isoprene cis-1,4 enriched regioselective polymerization and moderate catalytic activity for 1-hexene polymerization. Complexes 3a and 3b were studied as catalysts for methyl methacrylate polymerization reaction under different conditions and were found to show moderate to high catalytic activity. [ABSTRACT FROM AUTHOR]

A number of new sulfur-bridged tridentate [OSO] bisphenolato-based ligand precursors S(2-CH2-4-tBu-6-R-C6H2OH)2 [R = CMe3 (H2L1), CMe2Ph (H2L2), CMePh2 (H2L3), CPh3 (H2L4), and C(p-Tol)3 (H2L5)] were synthesized by reactions of Na2S·9H2O with 2 eq. of the corresponding 2-(bromomethyl)-4-(tert-butyl)-6-R-phenol. Their neutral titanium complexes [S(2-CH2-4-tBu-6-R-C6H2O)2]TiCl2 [R = CMe3 (1), CMe2Ph (2), CMePh2 (3), CPh3 (4), and C(p-Tol)3 (5)] were synthesized in high yields by direct HCl-elimination reactions of TiCl4 with the corresponding ligand precursors in toluene. Ionic titanium complexes [NHEt3][S(2-CH2-4-tBu-6-R-C6H2O)2TiCl3] [R = CMe3 (6), CMePh2 (7)] and [NH2Et2][S(2-CH2-4-tBu-6-R-C6H2O)2TiCl3] [R = CMe3 (8) and CMePh2 (9)] were obtained in high yields from the reactions of TiCl4 with the corresponding ligand precursors in the presence of 2 eq. of triethylamine or diethylamine. Neutral zirconium complexes [S(2-CH2-4-tBu-6-R-C6H2O)2]ZrCl2(THF) [R = CMe2Ph (10·THF), and CMePh2 (11·THF)] were synthesized by reactions of ZrCl4 with 1 eq. of the dilithium salt of the corresponding ligand precursors Li2L in THF. The new titanium and zirconium complexes were characterized by 1H and 13C NMR, IR and elemental analyses. The molecular structures of complexes 4, 6 and 10·THF were determined by single-crystal X-ray diffraction analysis. The X-ray crystallography analysis reveals that titanium complex 4 has a five-coordinating environment surrounding the central metal atom, while the titanium complex 6 and the THF-solvated zirconium complex 10·THF possess a six-coordinating pseudo-octahedral environment around the central metal atom. Upon activation with MAO or AliBu3/Ph3CB(C6F5)4, all these titanium and zirconium complexes exhibit moderate to high catalytic activities for ethylene polymerization and ethylene/1-hexene copolymerization with moderate to high comonomer incorporation, and the ionic titanium complexes 6, 7, 8 and 9 show lower catalytic activity than their corresponding neutral complexes under similar conditions. [ABSTRACT FROM AUTHOR]

A series of new half-sandwich secondary amine-coordinated dichlorochromium complexes chelated by 2-(tetramethylcyclopentadienyl)benzylamine ligands, 2-Me4CpC6H4CH2(R)NHCrCl2 [R = iPr (1), Cy (2), Ph (3), 4-MePh (4), 2,6-Me2Ph (5), 2,6-Et2Ph (6)], have been synthesized from the reactions of CrCl3(THF)3 with the dilithium salts of the corresponding ligands in THF, followed by the addition of 1/2 eq. of H2O to the reaction mixtures. The isolated yields of the chromium complexes were found to increase with the increase in the amount of H2O introduced and reach the highest values (66–76%) when 1/2 eq. of H2O is added. Attempts to isolate the 2-(tetramethylcyclopentadienyl)benzylamidochromium complexes, 2-Me4CpC6H4CH2(R)NCrCl, were not successful. The new dichlorochromium complexes were characterized by IR, 1H NMR, EPR, and UV/Vis spectroscopy and elemental analyses, and the molecular structures of complexes 1, 5 and 6 were determined by X-ray crystallography. The X-ray crystallographic analysis reveals that these chromium complexes possess a three-legged piano-stool geometry with the amine N atom in a mitered six-membered chelating ring and the two chloride atoms as the legs. Upon activation with AlR3 and Ph3CB(C6F5)4, complexes 1–6 exhibit reasonable catalytic activity for ethylene polymerization and copolymerization with 1-hexene, producing polyethylenes with moderate to high molecular weights and poly(ethylene-co-1-hexene)s with moderate comonomer incorporation which are typical linear low-density polyethylenes (LLDPE). Complex 4 was found to show higher catalytic activity for ethylene homo- and co-polymerization than other complexes under similar conditions, while complex 3 produced poly(ethylene-co-1-hexene)s with the highest comonomer incorporation. [ABSTRACT FROM AUTHOR]