The compound Na2Ti(CF3COO)6(CF3COOH)2 was synthesized as colorless crystals, extremely unstable in air, by the reaction of TiCl4 with trifluoroacetic acid and sodium trifluoroacetate. Crystallographic studies have shown that this sodium trifluoroacetatotitanate is the first example of a tetravalent titanium carboxylate [Ti(RCOO)6]2– containing titanium in an octahedral environment of oxygen atoms of carboxylate groups. Thermal decomposition of Na2Ti(CF3COO)6(CF3COOH)2 in an argon atmosphere results in the complex fluoride Na2TiF6. 相似文献
Syntheses of titanatranes containing [(O-2,4-Me2C6H2-6-CH2)2-{O(CH2)nCH2}]N3− (n = 1,2) have been explored. Catalytic activity for ethylene polymerization by Ti2(OiPr)2{[(O-2,4-Me2C6H2-6-CH2)2(µ2-OCH2-CH2)]N}2 ( 1a ) - MAO catalyst increased at high temperature; the activity also increased upon addition of AlMe3. Ti(O- 2,6-iPr2C6H3){[(O-2,4-Me2C6H2-6-CH2)2(OCH2CH2)]N} ( 1c ) showed higher activity than 1a under the same conditions. Ti{[(O-2,4-Me2C6H2-6-CH2)2(HOCH2CH2CH2)]N}2 was isolated from the reaction of Ti(OiPr)4 with bis(2-hydroxy-3,5-dimethylbenzyl)-propanolamine; the structure was determined by X-ray crystallography. 相似文献
A series of Cp2Ti(SB)Cl complexes, whereSB is the anion of bidentate Schiff bases derived from salicylaldehyde and different primary aminesviz o-anisidine,m-anisidine,o-phenetidine,o-chloroaniline,m-chloroaniline,m-nitroaniline, α-naphthylamine and benzylamine, have been synthesised by the reaction of dichloro-bis(cyclopentadienyl) titanium(IV),
Cp2TiCl2, and bidentate Schiff base (sbh) in a 1:1 molar ratio in refluxingthf in the presence of triethylamine. The new derivatives have been characterised on the basis of their elemental analyses, conductance
measurements and spectral (IR,1Hnmr and electronic) studies 相似文献
The molecular structure of enigmatic “poly(aluminium-methyl-methylene)” (first reported in 1968) has been unraveled in a transmetalation reaction with gallium methylene [Ga8(CH2)12] and AlMe3. The existence of cage-like methylaluminomethylene moieties was initially suggested by the reaction of rare-earth-metallocene complex [Cp*2Lu{(μ-Me)2AlMe2}] with excess AlMe3 affording the deca-aluminium cluster [Cp*4Lu2(μ3-CH2)12Al10(CH3)8] in low yield (Cp*=C5Me5). Treatment of [Ga8(CH2)12] with excess AlMe3 reproducibly gave the crystalline dodeca-aluminium complex [(CH3)12Al12(μ3-CH2)12] (MAM-12). Revisiting a previous approach to “poly(aluminium-methyl-methylene” by using a (C5H5)2TiCl2/AlMe3 (1 : 100) mixture led to amorphous solids displaying solubility behavior and spectroscopic features similar to those of crystalline MAM-12. The gallium methylene-derived MAM-12 was used as an efficient methylene transfer reagent for ketones. 相似文献
Perfluoroalkyl (RF) titanocene reagents [Cp2TiIIIRF] synthesized via [Cp2TiIIICl] rather than [Cp2TiII] show new types of perfluoroalkylation reactions. The [Cp2TiIIIRF] reagents exhibit a wide variety of reactivity with carbonyl compounds including esters and nitriles, and selectivities far higher than those reported for conventional RFLi and RFMgX reagents. 相似文献
The polycondensation of bis(hydroxyethylene) terephthalate and its oligomers to PET catalyzed by different chelated and non‐chelated titanium catalysts in a lab‐scale stirred‐tank reactor and differential scanning calorimeter were investigated. Different titanium compounds showed different activity and selectivity. The nature of catalyst ligands plays an important role in catalyst efficiency. Non‐chelated titanium derivatives were more active and less selective. Reaction progress is characterized by an initial inhibition period depending on the type of catalyst. The original titanium compounds used are precursors and are probably activated by a ligand exchange reaction.
Titanium(IV) in sulphuric, perchloric and hydrochloric acid media reacts with 3-hydroxy-2-methyl-1-(4-tolyl)-4-pyridone (HY) to give a complex which is extractable into chloroform. The composition of the extractable complex depends on the acidity of the aqueous phase and on which mineral acid is used. The mixed titanium-perchlorate-HY complex which is formed in the presence of excess of perchlorate is the most suitable for the spectrophotometric determination of titanium. The molar absorptivity of the complex is 1.6×1041·mole–1·cm–1 at 355 nm. The optimum titanium concentration range is 0.5–6,g/ml. The method has been successfully applied to the determination of titanium in samples of bauxite and alumina refractory. 相似文献
Abstract Spectrometric studies on the complexation of Ti(IV) with a new organic reagent obtained by coupling 3-methyl-1-phenyl-5-pyrazolone with diazotized 3-amino-4-hydroxy-benzene-sulphonic acid were carried out. A 1:2 Ti(IV):reagent complex, which is soluble in water, is formed at pH 5–6.2. The maximum absorbance of the complex lies at λ =520nm, where the absorbance of the reagent is very low. The molar absorptivity at this wavelength is 5 × 103 L mol?1 cm?1; the value of log K is 8.0 ± 0.2. at 20 ± 1°C and pH=5.6. 相似文献