Syntheses, Characterization, and the Ethylene (Co-)Polymerization Screening of 2-Benzimidazolyl-N-phenylquinoline-8-carboxamide Half-Titanocene Chlorides

Abstract

A series of 2-benzimidazolyl-N-phenylquinoline-8-carboxamide half-titanocene chlorides, CpTiLCl (C1−C6: Cp = η5-C5H5; L = 2-(1H-benzo[d]imidazol-2-yl)-N-(2,6-R1-4-R2-phenyl)quinoline-8-carboxamide derivatives; C1: R1 = i-Pr, R2 = H; C2: R1 = Et, R2 = H; C3: R1 = Me, R2 = H; C4: R1 = Me, R2 = Me; C5: R1 = H, R2 = H; C6: R1 = F, R2 = H), have been synthesized by the stoichiometric reaction of half-titanocene trichlorides with the corresponding potassium 2-benzimidazolyl-N-phenylquinoline-8-carboxamide. All complexes are fully characterized by elemental and NMR analyses, as well as single-crystal X-ray diffraction for complexes C1, C2, and C6. In addition, the oxo-bridged dinuclear complex C7 was separated from the solution of C6 in air. These complexes, C1−C6, activated with methylaluminoxane (MAO), exhibit high catalytic activities toward both ethylene polymerization and copolymerization of ethylene with α-olefins. According to the catalytic system of C1/MAO, both elevating the reaction temperature and increasing the ratio of MAO to titanium precursor enhance the productivities; however, the molecular weights of the resultant polymers obtained decrease against their higher activities. Moreover, copolymerizations of ethylene with either 1-hexene or 1-octene effectively produce copolymers with incorporated comonomers of 2.0−5.0% mol.

Nickel halide complexes bearing 2-benzimidazolyl-N-arylquinoline-8-carboxamide derived ligands: Synthesis, characterization and catalytic behavior towards ethylene oligomerization and the vinyl polymerization of norbornene

“…All 2-(benzimidazol-2-yl)-N-phenylquinoline-8-carboxamide ligands (L1eL6) were prepared according to our previous procedure [73]. As shown in Scheme 1, the nickel halide complexes (Ni1eNi12) were synthesized in high yield as yellow powders by the stoichiometric reaction of NiCl 2 $6H 2 O or (DME)NiBr 2 with the corresponding ligand (L1eL6) in ethanol at room temperature.…”

“…Methylaluminoxane (MAO, a 1.46 M solution in toluene) and modified methylaluminoxane (MMAO, 1.93 M in heptane, 3A) were purchased from Akzo Nobel Corp. Diethylaluminium chloride (DEAC, 0.50 M in toluene) was obtained from Beijing Yansan Petrochemical Co. The 2-(benzimidazol-2-yl)-N-phenylquinoline-8-carboxamide derivatives used as ligands (L1eL6) were prepared according our previous procedures [73]. Other reagents were purchased from Acros Chemicals or local suppliers.…”

“…Investigations using the same ligands but with different metals is attractive from the point of view of comparative studies, particularly in terms of catalysis. Recently, 2-benzimidazolyl-N-phenylquinoline-8-carboxamide ligands were deployed in half-titanocene pre-catalysts and were found to perform with high activity during ethylene (co-)polymerization [73], and also in chromium pre-catalysts which showed high activity for ethylene oligo-/polymerization [74]. Herein, the title nickel complexes are synthesized and fully characterized.…”

Half-titanocene 5-t-butyl-2-(1-(arylimino)methyl)quinolin-8-olate chlorides: Synthesis, characterization and ethylene (co-)polymerization behavior

“…These observations were consistent to previously reported results. 17 Employing the optimum conditions of Al/Ti ratio 3000 at 40°, all complexes C1-C5 were investigated for ethylene polymerization (Table 3), which indicated the best performance was for complex C2 with an activity of 4.8 × 10 5 g•mol -1 (Ti)•h -1 . In comparison with the catalytic results obtained for the titanium 2-iminoquinolin-8-olates, 13,14,15 especially the half-titanocene 2-iminoquinolin-8olates, 13,14,15b for the current complex pre-catalysts, the presence of the additional t-butyl group did not have a positive influence.…”

Living polymerization of 1,3-butadiene catalyzed by half-titanocene complex bearing dibenzhydryl-substituted aryloxide ligand

“…The solid state structure of 2c is similar to our previously reported bulky aryloxide half-titanocene complexes, which adopts three-legged distorted tetrahedral geometry around the metal center [23] . The selected Ti-C (in the Cp ring) bond lengths of the complexes are ranging from 0.2323 nm to 0.2405 nm and the observed singlet of Cp ring in the NMR spectra indicates their conjugated characteristics [26] . [27] .…”