Syntheses, Characterization and Crystal Structures of Two Novel Oxazoline Based Titanium Complexes

Two novel titanium compounds [（E）-N＇-（2,6-diisopropylphenyl）-N-（2-（4,4-dimethyl-4,5-dihydrooxazol-2-yl）phenyl）benzimidamido]titanium trichloride（1） and [N-（2-（4,4-dimethyl-4,5-dihydrooxaz-ol-2-yl）phenyl）-6-（2,4,6-triisopropyl-phenyl） pyridin-2-amido]titanium trichloride（2） were synthesized by reacting the corresponding ligand with diethylaminetitaniumtrichloride in equal molar ratios. The compounds were characterized with 1H, 13 C NMR, elemental analysis and single-crystal X-ray diffraction analysis. The geometry of both compounds is distorted octahedron. The three nitrogen and one chlorine atoms are in the equatorial plane. Compound 1 crystallizes in orthorhombic system, space group P212121 with a = 10.3520（4）, b = 16.5750（7）, c = 17.1530（7） , Z = 4 and V = 2943.2（2）3. Compound 2 crystalizes in the monoclinic system, space group P21/n with a = 15.6400（11）, b = 10.12.60（7）, c = 22.9120（14）, Z = 4 and V = 3558.5（4）3. The synthesized compounds were employed for ethylene polymerization catalysis. Both complexes showed moderate activity when activated with dry methylaluminoxane（d MAO） and complex 1 produced very high molecular weight polyethylene.

Fe-doped TiO_2/SiO_2 nanofibrous membranes with surface molecular imprinted modification for selective photodegradation of 4-nitrophenol

In this study, Fe-doped TiO2/SiO2 （Fe@TS） nanofibrous membranes with molecular imprinted modification, were fabricated by a combination of sol-gel process, electrospinning, calcination and liquid phase deposition techniques, The precursor sol was prepared from one-pot condensation of poly （vinylpyrrolidone）, ferric chloride hexahydrate, tetraethyl orthosilicate and titanium n-butoxide in the mixture solvents of N,N-dimethylformamide and ethyl alcohol. Fibrous membrane wasthen fabricated by electrospinning, followed by calcination to form the Fe@TS composite. The physicochemical properties of Fe@TS were characterized. Thereafter, 4-nitrophenol （4NP） was used as the template to deposit onto nanofibrous Fe@TS membranes, with a thin layer of molecular imprinted polymer in liquid phase. The photodegradation capabilities of 4NP and methyl orange wereexamined in both single and binary systems. The results demonstrated that molecular imprinted Fe@TS membranes exhibited excellent selectivity for photodegradation of 4NP.

Trichlorozirconium η~2-Hydrazonides： Synthesis, Characterization and Their Catalytic Behavior toward Ethylene Polymerization

The trichlorozirconium η~2-hydrazonides（R=H, A; R=CH_3, B） were synthesized through the finely controlled stoichiometrical reactions of anhydrous zirconium tetrachloride with the lithium salt of either 1-（furan-2-ylmethylene）-2-phenylhydrazonide or 1-（furan-2-ylethylidene）-2-phenyl hydrazonide in the solvent tetrahydrofuran（THF）, respectively. These complexes were highly sensitive to air and moisture due to solely using less bulky ligand of hydrazonides. The molecular structures of the title complexes, determined by means of single crystal X-ray diffraction, were found to be the distorted pentagonal bipyramid geometry around zirconium atom, with three chlorides and the hydrazonato ligand acting as the η~2-coordination mode as well as two incorporated THF molecules. Upon activation with either methylaluminoxane（MAO） or modified methylaluminoxane（MMAO）, both complexes A and B exhibited catalytic activities toward ethylene polymerization, producing polyethylenes with ultra-high molecular weights.