Reaction Of TiCl4 Research Articles

Antidiabetic and antioxidant studies of novel synthesized titanium (IV) complex: Design, synthesis, in‐silico docking and in‐vitro studies

[{TiCl3}2(C3N3S3H)] (where C3N3S3H is Trithiocyanuric acid) was designed and synthesized by the reaction of TiCl4 and trithiocyanuric acid in 2:1 M ratio under stirring and refluxing condition using THF solvent. The synthesized Titanium (IV) complex was characterized by various spectroscopic techniques like FT‐IR, NMR, MASS, XRD, UV–visible spectrophotometer and elemental analysis (CHNSO). Moreover, in‐silico docking studies of the ligand and its Ti (IV) complex were carried out by AutoDockTools‐1.5.6 to study interactions of the complex under study with the receptor protein. Afterwards, both ligand and synthesized Ti (IV)complex were screened for the antioxidant and antidiabetic potential by in‐vitro method. The antioxidant potential was investigated by using DPPH (2,2‐diphenyl‐1‐picrylhydrazyl) radical scavenging assay where ligand exhibited moderate activity while Ti (IV) complex presented significant antioxidant activity. Following, alpha‐amylase enzyme inhibition was investigated using iodine‐starch inhibition assay. It was found that the ligand was inactive (showed no α‐amylase inhibition activity) while the Ti (IV)complex was a potent α‐amylase inhibitor. Furthermore, the experimentally obtained results were also complimented by the in‐silico results.

Modeling the Structural Heterogeneity of Vicinal Silanols and Its Effects on TiCl4 Grafting onto Amorphous Silica

Molecular metal complexes such as MClx react readily with hydroxyl-terminated surfaces to produce some of the “single-atom” catalysts used in important large-scale commercial reactions, including olefin metathesis, polymerization, and epoxidation. While the local oxide environment can vary at each metal site, the manner and degree to which these differences impact the catalytic activities of individual sites are poorly understood. In this work, we develop a computational framework to model the grafting of metal complexes onto amorphous supports and apply the framework to examine TiCl4 grafting onto amorphous silica. We use density functional theory (DFT) to calculate free energies for TiCl4 reactions at vicinal silanol sites. The kinetics and thermodynamics depend on the dihedral angle between the silanols. Vicinal silanol pairs with small dihedral angles are predicted to yield bipodal [(≡SiO)2TiCl2] sites initially, but they react further with TiCl4 vapor to give vicinal pairs of monopodal sites, [ ≡ SiOTiCl3]. In contrast, silanol pairs with large dihedral angles yield vicinal pairs of monopodal Ti sites directly. The DFT results were used to construct a population balance model to describe the kinetics of TiCl4 grafting onto nonuniform sites of an atomistic model for amorphous silica. The solution of the population balance model predicts that the majority of the vicinal pairs graft as bipodal [(≡SiO)2TiCl2] sites first and then slowly convert to monopodal [≡SiOTiCl3] sites. The predictions provide a plausible explanation for the variability in the populations of monopodal and bipodal sites previously reported for TiCl4 grafting.

Synthesis, crystal structure and thermal properties of Na2Ti(CF3COO)6(CF3COOH)2

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.

Ionic Liquid-Based Low-Temperature Synthesis of Crystalline Ti(OH)OF·0.66H2O: Elucidating the Molecular Reaction Steps by NMR Spectroscopy and Theoretical Studies.

We present an in-depth mechanistic study of the first steps of the solution-based synthesis of the peculiar hexagonal tungsten bronze-type Ti(OH)OF·0.66H2O solid, using NMR analyses (1H, 13C, 19F, and 11B) as well as modeling based on density functional theory (DFT) and ab initio molecular dynamics (AIMD) simulation. The reaction uses an imidazolium-based ionic liquid (IL, e.g., Cxmim BF4) as a solvent and reaction partner. It is puzzling, as the fluorine-rich crystalline solid is obtained in a “beaker chemistry” procedure, starting from simple compounds forming a stable solution (BF4–-containing IL, TiCl4, H2O) at room temperature, and a remarkably low reaction temperature (95 °C) is sufficient. Building on NMR experiments and modeling, we are able to provide a consistent explanation of the peculiar features of the synthesis: evidently, the hydrolysis of the IL anion BF4– is a crucial step since the latter provides fluoride anions, which are incorporated into the crystal structure. Contrary to expectations, BF4– does not hydrolyze in water at room temperature but interacts with TiCl4, possibly forming a TiCl4 complex with one or two coordinated BF4– units. This interaction also prevents the heavy hydrolysis reaction of TiCl4 with H2O but—on the other side—spurs the hydrolysis of BF4– already at room temperature, releasing fluoride and building F-containing Ti(OH)xCl4–xFy complexes. The possible complexes formed were analyzed using DFT calculations with suitable functionals and basis sets. We show in addition that these complexes are also formed using other titanium precursors. As a further major finding, the heating step (95 °C) is only needed for the condensation of the Ti(OH)xCl4–xFy complexes to form the desired solid product but not for the hydrolysis of BF4–. Our study provides ample justification to state a “special IL effect”, as the liquid state, together with a stable solution, the ionic nature, and the resulting deactivation of H2O are key requirements for this synthesis.

Facile synthesis hierarchical porous structure anatase–rutile TiO2/g-C3N4 composite for efficient photodegradation tetracycline hydrochloride

The anatase–rutile TiO2/g-C3N4 (denoted as ARC) photocatalyst with hierarchical porous structure is synthesized via an impregnation-calcination method utilizing TiCl4 and melamine as precursor. The content of g-C3N4, and the relative content of the anatase and rutile in ARC can be regulated via controlling the dosage of melamine. Furthermore, the highly acidic environment producing by hydrochloric acid which is generated via hydrolysis reaction of TiCl4 has significantly impact for forming the hierarchical porous structure of ARC. Comparing with g-C3N4, the specific surface area of ARC-5 (61.2 m2·g−1) is 7.2 times than that of g-C3N4. Among all the resultant composites, the ARC-5 exhibits the highest visible-light photocatalytic property for degrading tetracycline hydrochloride (TC-HCl, 10 mg·L-1). The degradation rate of TC-HCl is 92% in 60 min with ARC-5 as photocatalyst, and the kinetic constant (k) of ARC-5 is 4.4 times than that of g-C3N4. The favorable catalytic property of ARC-5 should be attributed to the close-knit interface contact and high surface area, which could broaden the spectra absorption range, facilitate the carriers separation, provide more active sites and enhance the transfer rate of reactant and product. Moreover, radical trapping experiments shows that h+ and •O2– have vital function for degrading TC-HCl.

Ti(fpin)3]2−: a structurally characterized transition metal tris(perfluoropinacolato) complex

AbstractThe reaction of TiCl3 ⋅ 3THF with perfluoropinacol (H2fpin), triethylamine and silver nitrite in acetonitrile yielded in the formation of the first tris(perfluoropinacolato) complex with a transition metal, (HNEt3)3[TiIV(fpin)3]NO2 (1). The compound was fully characterized with IR and UV‐vis spectroscopy as well as elemental analysis and single crystal X‐ray diffraction. The structure of 1 is compared with that of known homoleptic titanium(IV) compounds and the only other structurally resolved tris(perfluoropinacolato)metallate, the stannate(IV) (HNEt3)2[Sn(fpin)3] ⋅ 2acetone.

Reaction mechanisms of chlorine reduction on hydroxylated alumina in titanium nitride growth: First principles study

The nature of the electronic interaction of precursor molecules with functionalized surfaces are still uncertain. Here, DFT calculations were performed to study the dissociative reactions of TiCl4 on non-hydroxylated and hydroxylated α-Al2O3 (0 0 0 1) surface based on DFT calculation. For non-hydroxylated α-Al2O3 (0 0 0 1) surface, residual Cl atoms from the dissociative reactions hinder another TiCl4 molecule to be adsorbed on non-hydroxylated α-Al2O3 surface, which are known to greatly degrade the performance of memory devices. We found that the removal of those Cl adatoms is energetically difficult on the non-hydroxylated α-Al2O3 (0 0 0 1) surface due to the strong bonding nature of ClAl bond, which was additionally confirmed by charge density difference and Bader charge analysis. In contrast, hydroxyl functional group worked as a catalysis for the dissociative reactions of TiCl4 molecules by lowering activation energy for the successive removal process of Cl adatoms as HCl gas on the hydroxylated surface. These results imply that the electronic interaction between highly reactive molecule and surface functional group should be deeply understood in order to design the ALD process of future memory devices.

Synthesis, Structural, and Physicochemical Characterization of a Ti6 and a Unique Type of Zr6 Oxo Clusters Bearing an Electron-Rich Unsymmetrical {OON} Catecholate/Oxime Ligand and Exhibiting Metalloaromaticity.

The chelating catechol/oxime ligand 2,3-dihydroxybenzaldehyde oxime (H3dihybo) has been used to synthesize one titanium(IV) and two zirconium(IV) compounds that have been characterized by single-crystal X-ray diffraction and 1H and 13C NMR, solid-state UV-vis, and ESI-MS spectroscopy. The reaction of TiCl4 with H3dihybo and KOH in methanol, at ambient temperature, yielded the hexanuclear titanium(IV) compound K2[TiIV6(μ3-O)2(μ-O)3(OCH3)4(CH3OH)2(μ-Hdihybo)6]·CH3OH (1), while the reaction of ZrCl4 with H3dihybo and either nBu4NOH or KOH also gave the hexanuclear zirconium(IV) compounds 2 and 3, respectively. Compounds 1-3 have the same structural motif [MIV6(μ3-Ο)2(μ-Ο)3] (M = Ti, Zr), which constitutes a unique example with a trigonal-prismatic arrangement of the six zirconium atoms, in marked contrast to the octahedral arrangement of the six zirconium atoms in all the Zr6 clusters reported thus far, and a unique Zr6 core structure. Multinuclear NMR solution measurements in methanol and water proved that the hexanuclear clusters 1 and 3 retain their integrity. The marriage of the catechol moiety with the oxime group in the ligand H3dihybo proved to be quite efficient in substantially reducing the band gaps of TiO2 and ZrO2 to 1.48 and 2.34 eV for the titanium and zirconium compounds 1 and 3, respectively. The application of 1 and 3 in photocurrent responses was investigated. ESI-MS measurements of the clusters 1 and 3 revealed the existence of the hexanuclear metal core and also the initial formation of trinuclear M3 (M = Ti, Zr) building blocks prior to their self-assembly into the hexanuclear M6 (M = Ti, Zr) species. Density functional theory (DFT) calculations of the NICSzz scan curves of these systems revealed that the triangular M3 (M = Ti, Zr) metallic ring cores exhibit pronounced metalloaromaticity. The latter depends upon the nature of the metallic center with NICSzz(1) values equal to -30 and -42 ppm for the Ti (compound 1) and Zr (compound 2) systems, respectively, comparable to the NICSzz(1) value of the benzene ring of -29.7 ppm calculated at the same level of theory.

New insight into reaction mechanisms of TiCl4 for the synthesis of TiO2 nanoparticles in H2O-assisted atmospheric-pressure CVS process

Crystalline anatase TiO2 nanoparticles were synthesized in the gas phase using an H2O-assisted atmospheric-pressure CVS process. Simultaneous oxidation/hydrolysis of TiCl4 in the H2O-assisted APCVS process demonstrates the feasibility of facile fabrication and the designed synthesis of TiO2 nanoparticles in atmospheric pressure. Kinetics and thermodynamics studies of TiCl4 reactions in the gas phase illustrated oxidation or hydrolysis domination theoretically and were confirmed by experimental runs. Effects of H2O/O2 ratio on the reactions mechanisms, phase formation, size characteristics, morphology, and purity of TiO2 nanoparticles were experimentally studied using various analytical techniques including TEM, XRD, SAED, and TG-DTA. The synthesized particles were significantly finer with higher crystallinity than those produced by the solitary oxidation process. The average size of TiO2 nanoparticles was 12 ± 4 nm under simultaneous oxidation/hydrolysis, while that was 34 ± 5 nm without hydrolysis. Hydrolysis dominates in lower temperatures caused by lower activation energy and higher kinetics of hydrolysis reaction.

Optically Transparent Colloidal Dispersion of Titania Nanoparticles Storable for Longer than One Year Prepared by Sol/Gel Progressive Hydrolysis/Condensation.

The molecular catalyst sensitized system (MCSS), where an excited molecular catalyst adsorbed on a semiconductor such as TiO2 injects electrons to the conduction band of the semiconductor leading to hydrogen evolution/CO2 reduction coupled with an oxidation of water on the molecular catalyst, has been one of the most probable candidates in the approach to artificial photosynthesis. For a full utilization of visible light, however, a serious light scattering of the aqueous suspension of TiO2 in the visible region, which is generally experienced, should be avoided. Here, we report a preparation of optically transparent colloidal dispersion of TiO2 by the sol/gel reaction of TiCl4 through progressive hydrolysis/condensation under the basic condition without any calcination processes. The TiO2 nanoparticles (TiO2(NPs)) obtained were characterized as an amorphous particle (∼10-15 nm) having a microcrystal domain of anatase within several nm by XRD, Raman spectroscopies, XRF, XAFS, TG/DTA, and HRTEM, respectively. The energy-resolved distribution of carrier electron traps in TiO2(NPs) as a fingerprint of TiO2 was characterized through reversed double-beam photo-acoustic spectroscopy to have a close similarity to that of TiO2(ST-01) as well as the observation of carrier traps by transient absorption spectroscopy. Though the powder TiO2(NP) itself was not dispersed well in aqueous solution, the wet TiO2(NPs) as prepared before being dried up provided a completely transparent aqueous dispersion under the acidic condition (1 M HCl). Addition of methanol enabled the colloidal dispersion (TiO2(NPs, MeOH/H2O, 0.1 M HCl)) to keep the optical transparency for longer than 1 year (550 days), which is the first example of TiO2 dispersion storable for such a long period. TiO2(NPs, MeOH/H2O) exhibited a moderate photocatalytic reactivity of H2 evolution with a quantum yield of ∼2.6% upon 365 nm light irradiation. An optically transparent thin film of TiO2(NPs, MeOH/H2O) was also successfully prepared on a glass plate to exhibit an enhanced hydrophilicity upon UV light irradiation.

Green approach and ease synthesis of C/N-codoped TiO2 nanocrystals for photodegradation of endocrine

Carbon species and nitrogen–codoped anatase TiO2 (C/N-codoped TiO2) nanocrystals with uniform particle size and high crystallinity were synthesized, employing hexamethylenetetramine (HMTA) as a nitrogen and carbon source throughout solvothermal reaction of TiCl4 and HMTA at different contents (0.5 g, 1 g, 1.5 g, and 2 g HMTA). The synthesized photocatalysts were assessed by photocatalytic degradation of resorcinol as a probe of potent endocrine-disrupting chemicals (EDCs) compared with commercial P-25 photocatalyst. Raman spectra and XRD results confirmed that the obtained C/N-codoped TiO2 is anatase TiO2 phase with 10–20 nm nanocrystallite sizes. For resorcinol photo-oxidation in aerated aqueous solution, C/N-codoped TiO2 nanocrystals synthesized at 0.5 g HMTA (H0.5) showed the superior photocatalytic efficiency among all synthesized photocatalysts. H0.5 photocatalyst exhibited the outstanding photocatalytic performance, which is 1.2 and 2 times greater than that of commercial P-25 and pure TiO2. In addition, the rate constant of the H0.5 sample was enhanced 7.5 and 3 times than that of commercial P-25 and pure TiO2, respectively. The C/N-codoped TiO2 nanocrystals achieved high photocatalytic efficiency of up to 96% within 90 min. In contrast, the photocatalytic efficiency based on the commercial P-25 was 54%. The photocatalytic efficiency of C/N-codoped TiO2 was considerably enhanced, owing to its increase of photogenerated charge separation rate, smaller crystal size, narrower bandgap energy, and stronger light harvesting in wide visible region. Detailed mechanistic and kinetic studies through photodegradation of resorcinol in water were addressed.

SrCO3-modified brookite/anatase TiO2 heterophase junctions with enhanced activity and selectivity of CO2 photoreduction to CH4

Utilizing the abundant solar energy to chemically convert CO2 into high-energy chemical fuels such as CO, CH4 or CH3OH offers a way to address the serious concerns about the increasing atmospheric CO2 levels and the depletion of fossil fuels. Herein, a series of SrCO3-modified TiO2 composites have been synthesized by adding SrCl2 into a TiCl4 hydrothermal reaction solution. It is found that brookite TiO2quasi nanocubes with high phase purity (denoted as pristine TiO2) can be derived from the TiCl4 reaction solution, and the additive Sr2+ ions lead to the formation of SrCO3-modified TiO2 heterophase junctions (HPJs) containing brookite nanorods and anatase nanoparticles. When used the SrCO3-modified TiO2 HPJs (hereafter denoted as SrCO3/HPJs) as photocatalyst for CO2 photoreduction, significantly enhanced activity and selectivity for CO2 photoreduction to CH4 can be achieved as compared to the pristine TiO2. Especially, 1.0% SrCO3/HPJs composite shows CH4/CO production activities of 19.66/2.64 μmol g−1 h−1 with an overall photoactivity of 162.6 μmol g−1 h−1, which is 12.3 times of the pristine TiO2 that shows an overall photoactivity of 13.2 μmol g−1 h−1 with CH4/CO production activities of 0.79/3.46 μmol g−1 h−1. The brookite/anatase TiO2 HPJs can effectively promote the photogenerated charge separation and restrain the interfacial charge recombination, and the SrCO3 species on the TiO2 HPJs can act as an efficient synergistic catalyst to improve the CO2 adsorption and activation abilities, and thus cause the enhanced activity and selectivity for CO2 photoreduction to CH4. This work represents the first example of coupling TiO2 HPJs with alkaline earth metal carbonates for efficient CO2 photoreduction.

Crystallographic Insights into the Behavior of Highly Acidic Metal Cations in Ionic Liquids from Reactions of Titanium Tetrachloride with [1-Butyl-3-Methylimidazolium][X] Ionic Liquids (X = Chloride, Bromide, Tetrafluoroborate).

Highly charged metal ions are difficult to investigate in weakly coordinating ionic liquids (ILs) because of the insolubility of their solid forms, but the molecular liquid TiCl4 offers a way to react tetravalent metal ions in an IL. Reactions of TiCl4 with 1-butyl-3-methylimidazolium ([C4mim]+)-based ILs containing chloride or bromide lead to mixtures of highly metastable amorphous solids and small amounts of crystalline chlorotitanate salts including [C4mim]2[TiCl6] and two polymorphs of [C4mim]2[Ti2Cl10] in a manner not well correlated with stoichiometry or anion identity. The reaction of TiCl4 with [C4mim][BF4] yields crystals of the mixed fluoro-chloro complex [C4mim]2[Ti4F6Cl12], indicating spontaneous reaction of the IL ions to generate HF in situ. These unusual behaviors are explained in terms of the exceptionally high acidity of Ti4+ and the unusual behavior of TiCl4 among metal halides as a nonpolar molecular compound.

Synthesis and spectroscopic characterization of titanium pyridylanilido complexes as catalysts for the polymerization of 1,3-butadiene and isoprene

A series of titanium(IV) complexes of general formula TiCl3[N,N-(pyridin-2-ylalkyl)anilido, TiCl3L, 8–13, were prepared by reactions of TiCl4 with substituted (pyridin-2-ylalkyl)anilines, LH, and characterized by analytical and spectroscopic methods. Compound 10 was obtained by using TiI4 as titanium precursor. In the case of LH = 2,6-diisopropyl(pyridin-2-ylmethyl)aniline, 1, and 2,6-diisopropyl(pyridin-2-ylethyl)aniline, 2, the intermediate formation of TiCl4LH, 6–7, was detected, undergoing HCl elimination on heating to finally give 8 and 9. The products are not stable in coordinating solvents (thf, CH3CN). Ligand dissociation was observed from TiCl3(N,N-2,6-diisopropyl(pyridin-2-ylmethyl)anilido, 8, resulting in the formation of Ti2OCl6(CH3CN)4 and 2-(2,6-diisopropyl-phenylaminomethyl)pyridinium hexachlorotitanate. By reaction of TiCl3(thf)3 or TiI3 with 1 and 2 at ca 100 °C, the air sensitive derivatives TiCl2L, 14, and TiI2L, 15, were afforded.All titanium complexes were evaluated as catalysts for the polymerization of 1,3-butadiene and isoprene, in association with methylaluminoxane (MAO). The results indicate that the catalytic activity is strictly dependent on the nature of the ligands and the oxidation state of the metal, while the nature of the titanium complex has negligible influence on the selectivity.

Tuning Texture and Morphology of Mesoporous TiO₂ by Non-Hydrolytic Sol-Gel Syntheses.

The development of powerful synthetic methodologies is paramount in the design of advanced nanostructured materials. Owing to its remarkable properties and low cost, nanostructured TiO2 is widely investigated for applications such as photocatalysis, energy conversion or energy storage. In this article we report the synthesis of mesoporous TiO2 by three different non-hydrolytic sol-gel routes, and we investigate the influence of the synthetic route and of the presence and nature of the solvent on the structure, texture and morphology of the materials. The first route is the well-known ether route, based on the reaction of TiCl4 with iPr2O. The second and third routes, which have not been previously described for the synthesis of mesoporous TiO2, involve the reaction of Ti(OiPr)4 with stoichiometric amounts of acetophenone and benzoic anhydride, respectively. All materials are characterized by XRD, N2 physisorption and SEM. By playing with the non-hydrolytic route used and the reaction conditions (presence of a solvent, nature of the solvent, calcination), it is possible to tune the morphology and texture of the TiO2. Depending on the reaction conditions, a large variety of mesoporous TiO2 nanostructures could be obtained, resulting from the spontaneous aggregation of TiO2 nanoparticles, either rounded nanoparticles, platelets or nanorods. These nanoparticle networks exhibited a specific surface area up to 250 m2 g−1 before calcination, or up to 110 m2 g−1 after calcination.

Thermal atomic layer etching of HfO2 using HF for fluorination and TiCl4 for ligand-exchange

Thermal atomic layer etching (ALE) can be accomplished using sequential fluorination and ligand-exchange reactions. HF has been a typical fluorination reactant. Various metal reactants have been used for ligand-exchange, such as Sn(acac)2, Al(CH3)3, AlCl(CH3)2, and SiCl4. This study explored TiCl4 as a new metal chloride reactant for ligand-exchange. Thermal HfO2 ALE using HF and TiCl4 as the reactants was studied using in situ quartz crystal microbalance (QCM) measurements from 200 to 300 °C. The HfO2 films were etched linearly versus the number of HF and TiCl4 reaction cycles. The sequential HF and TiCl4 reactions were also self-limiting versus reactant exposure. The QCM studies observed a mass change per cycle (MCPC) of −10.2 ng/(cm2 cycle) at 200 °C and −56.4 ng/(cm2 cycle) at 300 °C. These MCPCs correspond to HfO2 etch rates of 0.11 Å/cycle at 200 °C and 0.59 Å/cycle at 300 °C. To explore the selectivity of thermal ALE using HF and TiCl4 as the reactants, spectroscopic ellipsometry (SE) measurements were also employed to survey the etching of various materials. The SE results revealed that HfO2 and ZrO2 were etched by HF and TiCl4. In contrast, Al2O3, SiO2, Si3N4, and TiN were not etched by HF and TiCl4. The etching selectivity can be explained by the reaction thermochemistry and the stability and volatility of the possible etch products. Al2O3 can also serve as an etch stop for HfO2 ALE.

Chiral Titanium(IV) Complexes Containing Polydentate Ligands Based on α-Pinene. Catalytic Activity in Sulfoxidation with Hydrogen Peroxide

The reaction of TiCl4–n(OiPr)n (n = 0, 2, 4) with various terpenoid preligands based on α-pinene, C7H6Me3(OH)(NCH2CH2G) (G = NH2, I; NHMe, II; OH, III), stereoselectively affords a series of new chiral titanium(IV) complexes. Such complexes are either octahedral, [TiCl2X(OC7H6Me3NCH2CH2G-κ3N,N,O)] (X = Cl, G = NH2, 1; X = OiPr, G = NH2, 2; G = NHMe, 3), or trigonal bipyramidal, [Ti(OiPr)3(OC7H6Me3NCH2CH2G-κ2N,O)] (G = NH2, 4; NHMe, 5) and [TiX(OiPr)(OC7H6Me3NCH2CH2O-κ3N,O,O*)] (X = Cl, 6; OiPr, 8), depending on the acidity of titanium, the reaction conditions and the nature of the pendant ending group of the terpenoid ligand. Density functional theory (DFT) calculations have been carried out to assess the stability of the multiple possible diastereoisomers allowing us to propose structural suggestions. The new titanium complexes efficiently catalyze the selective oxidation of various types of sulfides to either sulfoxides or sulfones using aqueous hydrogen peroxide, under mild conditions. All compounds ha...

Investigation of carbon phase evolutions in titanium nitride-carbon nanocomposites prepared in supercritical benzene with respect to their lithium storage capacity

Titanium nitride-carbon nanocomposites have been synthesized by the reaction of TiCl4 and NaN3 in supercritical benzene medium that also serves as a carbon source. The as-prepared precursor has been subjected to different heat treatments under ammonia and nitrogen atmospheres. The structure and chemical composition of the synthesized TiN-C nanocomposites are studied by X-ray diffraction (XRD) and CHN elemental analysis. Meanwhile, the nature of carbonaceous species and the respective carbon phase transitions during supercritical process and following heat treatments are further investigated by Raman spectroscopy, time of flight secondary ion mass spectrometry (ToF-SIMS), and their charge-discharge characteristics with respect to lithium storage. After 10 h NH3-treatment at 1000 ˚C carbonaceous phase transforms to graphene layered structure. The highly efficient mixed TiN conducting network and the internal defects between G layers induced by nitrogen doping improve rate capability and cycling performance of G sheets and provides a specific capacity of 381 mAh g-1 at charge/discharge (C/D) rate of 0.2 C. The enhanced electrochemical performance of the SIV nanocomposite is mainly due to improving the electronic/ionic conductivity and reducing charge transfer coefficient and increasing electrochemical surface area that are resulted from anchoring of TiN nanoparticles on graphene sheets.

Synthesis of ArOTiCl 3 complexes and their application for ethylene polymerization and copolymerization

In this article, novel olefin polymerization catalyst with lower cost and simple synthetic process were developed, ArOTiCl3 complexes [(2-OMeC6H4O)TiCl3(C1), (2,4-Me2C6H3O)TiCl3(C2), TiCl3(1,4-OC6H4O)TiCl3 (C3), TiCl3(1,4-OC6H2O-Me2-2,5) TiCl3(C4)] and corresponding (ArO)2TiCl2 complexes [TiCl2(OC6H4-OMe-2)2(C5) and TiCl2(OC6H3-Me2-2,6)2(C6)] have been synthesized by the reaction of TiCl4 with phenol, all these complexes were well characterized with 1H NMR,13C NMR, MASS and EA. When combined with methylaluminoxane (MAO), the ArOTiCl3 / MAO system shows high activity for ethylene copolymerization with 1-octene and copolymer was obtained with broaden molecular weight distribution (MWD). The 13C NMR result of polymer indicates that the 1-octene incorporation in polymer reached up to 8.29 mol%. The effects of polymerization temperature, concentration of polymerization monomer and polymerization time on the catalytic activity have been investigated.

Imines in the Titanium Coordination Sphere - Transformation of Imidoyl Chlorides to Nitrilium Ions

In the reaction of TiCl4 in benzene as solvent with the imidoyl chloride p-Tolyl(Cl)C=NPh (1) the abstraction of the chloride substituent is observed, leading to the nitrilium salt [p-Tolyl–C≡N–Ph]+[Ti2Cl9]– (2) in quantitative yield. The highly electrophilic salt 2 is characterized by IR- and NMR spectroscopy. The observed band for the C≡N stretching mode of 2 clearly indicates the formation of a nitrilium ion. Especially a characteristic line broadening of the 13C{1H}-NMR signals related to carbon atoms next to the nitrogen is observed. By 15N,1H-HMBC NMR experiments it is shown that the nitrogen signal of 2 is significantly shifted to high-field in relation to nitriles and imines. The molecular structure of 2 was confirmed by single-crystal X-ray diffraction. The C≡N bond length and the linearity of the C–C≡N–C unit in 2 confirm the triple bond character of this bond.