Reaction Of TiCl4 Research Articles

Titanium(IV) complexes with amidinate and/or hydrazido ligands

The complex [Ti 2Cl 4(NNMe 2) 2(py) 3] ( 1) has been prepared via the reaction of TiCl 4 with LiN(H)NMe 2, followed by treatment with pyridine. Preparation of the complex [TiCl(PhC{N(SiMe 3) 2} 2) 2(MeNNMe 2)] ( 2) was carried out by treatment of TiCl 4 with Li[PhC{N(SiMe 3) 2}]tmeda, followed by reaction with LiN(Me)NMe 2. The structures of 1 and 2 were determined by single crystal X-ray diffraction. The single crystal X-ray structure of Li[PhC{N(SiMe 3) 2}]tmeda ( 3) has also been determined.

Synthesis and Kinetics for Nanocrystalline Titanium Carbide upon Metallothermic Reduction of Liquid Chlorides

Nanosized titanium carbide particles were synthesized by the reaction of liquid magnesium and vaporized TiCl4 + CxCl4 (x = 1, 2) solution. Fine titanium carbide particles about 50 nm in size were successfully produced by combining Ti and C atoms released by the chloride reduction of magnesium, and a vacuum was then used to remove the residual phases of MgCl2 and excess Mg. Small amounts of impurities such as O, Fe, Mg, and Cl were detected in the product, but such a problem can be solved by more precise control of the process. The lattice parameter of the product was 0.43267 nm, which is near the standard value. With respect to the reaction kinetics, the activation energy for the reactions of TiCl4 + C2Cl4 and Mg was found to be 69 kJ/mol, which was about half of the value of the reaction with TiCl4 + CCl4, and the higher reactivity of the former contributed to an increase in the stoichiometry to the level of TiC0.96 and to a decrease in the free carbon content to below 0.3 wt %.

Preparation and Crystal Structures of a Series of Titanium(III) 9-BBN Hydroborate Complexes Containing Ti···H Agostic Interactions

9-BBN hydroborate complexes Ti{(mu-H)2BC8H14}3(THF)2 (1), Ti{(mu-H)2BC8H14}3(OEt2) (2), and [K(OEt2)4]-[Ti{(mu-H)2BC8H14}4] (4) were formed from the reaction of TiCl4 with K[H2BC8H14] in diethyl ether or THF. Ti{(mu-H)2BC8H14}3(PhNH2) (3) was isolated from the reaction of 2 with aniline in diethyl ether. In the formation of these complexes, Ti(IV) is reduced to Ti(III). The coordinated diethyl ether in 2 can be displaced by the stronger bases THF and aniline, to form 1 and 3, respectively. All of the compounds were characterized by single-crystal X-ray diffraction analysis. In complex 1, which contains two coordinated THF ligands, the titanium possesses a 17 electron configuration and there is no evidence for agostic interaction. Complexes 2 and 3 contain only one coordinated ether or aniline ligand, and the titanium possesses a 15 electron configuration. In these compounds, a C-H hydrogen on an alpha carbon on the BC8H14 unit of a 9-BBN hydroborate ligand forms an agostic interaction with the titanium. Criteria for assessing the existence of agostic interactions are discussed. As the potassium salt, the anion of complex 4 is more stable than the complexes 1-3. Organometallic anions of the type [ML4]- for titanium(III) are rare.

Trimethylsilyl-Substituted Indenyl-TiCl3 Half-Sandwich Complexes: Synthesis, Solid-State Structure, and Analysis of Substituent Effects

The regioselective synthesis of (η5:2-Me3SiC9H6)TiCl3 (4) was effected by the reaction of TiCl4 with 1,2-(Me3Si)2C9H6 (3). The solid-state structure of 4 is reported and compared with those of (η5:1-Me3SiC9H6)TiCl3 (6) and (η5:C9H7)TiCl3 (5). To investigate the position-dependent effect of the Me3Si group, UV−vis spectroscopic and cyclic voltammetric studies were carried out. The results obtained give an insight into the relative energy levels of the frontier molecular orbitals of the respective indenyl titanium trichlorides. Quantum-chemical modeling studies were carried out on 4−6 to demonstrate the influence of the Me3Si substituent effect with respect to the structural changes in the indenyl ligand and the Ti−D interaction (D = centroid of the five-membered ring of the indenyl moiety).

Titanium Complexes of Chelating, Dianionic O,S,O‐Bisphenolato Ligands: Syntheses, Characterisation, and Catalytic Activity

Titanium complexes based on 2,2′-thiobis[4-(1,1,3,3-tetramethylbutyl)phenolato] (tbop) are prepared by reaction of TiCl4 or Ti(NMe2)4 with the parent biphenol. Three new complexes are reported: [Ti2(μ-tbop-κ3O,S,O)(μ-tbop-κ2O,O)-(tbop-κ3O,S,O)Cl2] (1)·2 CH3CN, [Ti2(μ-tbop-κ3O,S,O)2Cl4] (2) and [Ti(tbop-κ3O,S,O)2] (3). Substitution of the chlorides in 1 and 2 by 2,6-diisopropylphenolato and imido (NtBu) ligands generates the new compounds [Ti2(μ-tbop-κ3O,S,O)2-Cl2(dipp)2] (4)·Et2O and [Ti2(μ-tbop-κ3O,S,O)2(NtBu)2-(NH2tBu)2] (5), respectively. Treatment of 5 with crude Me3-SiCl, containing Me3SiOH, produces [Ti(tbop-κ3O,S,O)Cl(OSiMe3)(NH2tBu)] (6). Reaction of 2 with an excess of NHiPr2 provides a mixture of compounds: ionic [NH2iPr2][Ti(tbop-κ3O,S,O)Cl3] (7)·CH2Cl2 and molecular [Ti2(μ-tbop-κ3O,S,O)2-Cl2(NiPr2)2] (8). The structures of 1–8 were confirmed by NMR spectroscopy; complexes 1, 5, 6 and 7 were further investigated by X-ray crystallography. Compounds 1, 2, 4 and 5, when supported on MgCl2 and activated with alkylaluminiums, effectively polymerise ethene. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)

New anilinotropone-based titanium complexes: synthesis, characterization and application as catalysts for olefin polymerization

New titanium(IV) dichloride complexes containing 2-anilinotropone ligands have been synthesized and characterized. Bis(ligand)titanium dichloride complexes 1 and 2 were synthesized from reaction of TiCl4(THF)2 with 2 equivalents of the corresponding sodium salts of 2-(2,6-diisopropylanilino)tropone (L1) and 2-(2,3,4,5,6-pentafluoroanilino)tropone (L2), respectively. The mixed cyclopentadienyl-anilinotropone compound 3 was synthesized by reaction of the lithium salt of with CpTiCl3. The Cp-mixed micro-O bimetallic complex 4 was also isolated as a by-product owing to the adventitious presence of moisture. The molecular structures 1-4 of have been determined by single-crystal X-ray diffraction studies. Complexes 1 and 2 are isostructural and exhibit a C2-symmetric octahedral geometry, with a trans(N,N), cis(O,O) arrangement in complex 1, but with a trans(O,O), cis(N,N) arrangement in complex 2. The Cp-mixed complex 3 has a distorted square-pyramidal structure with the Cp ligand in the apical position. Bimetallic complex 4 shows a similar coordination geometry for the five-coordinate titanium atom and a pseudo-tetrahedral coordination for the second metallic centre. All new complexes, when activated with methylaluminoxane, are active in the polymerization of ethylene and propene.

Synthesis of Uniform Titanium Nitride Nanocrystalline Powders via a Reduction–Hydrogenation–Dehydrogenation–Nitridation Route

A novel reaction of TiCl4 and NaNH2 at 450°–500°C for 12–24 h was performed for the preparation of TiN nanocrystalline powders. Powder XRD patterns indicated that the as‐synthesized powder was cubic‐phase TiN with a lattice constant a=4.225 Å. Transmission electron microscopy images showed that the TiN powders consisted of uniform particles with an average diameter of 10–20 nm. The binding energies of Ti2p3/2 and N1s core levels at the position of 455.50 and 396.96 eV, respectively, were detected by X‐ray photoelectron spectra. Four peaks, related to transverse acoustic, longitudinal acoustic, second‐order acoustic, and transverse optical (TO) modes of TiN, respectively, were observed in the Raman spectra of TiN particles. A very reasonable formation mechanism of TiN nanocrystalline powders was proposed.

Synthesis, Structures, and Reactions of Titanium, Scandium, and Yttrium Complexes of Diamino-bis(phenolate) Ligands: Monomeric, Dimeric, Neutral, Cationic, and Multiply Bonded Derivatives

New groups 3 and 4 organometallic and coordination compounds supported by the tetradentate diamino-bis(phenolate) ligands O2tBuNN‘ and O2MeNN‘ are reported [H2O2RNN‘ = (2-C5H4N)CH2N(2-HO-3,5-C6H2R2)2 where R = tBu or Me] along with some comparative studies with the tridentate amino-bis(phenolate) ligand O2tBuN (H2O2tBuN = nPrN(2-HO-3,5-C6H2tBu2)2). Reaction of Na2O2tBuNN‘ with ScCl3 and pyridine in THF gave monomeric Sc(O2tBuNN‘)Cl(py) (2), whereas Na2O2MeNN‘ gave the dimeric phenoxy-bridged Sc2(O2MeNN‘)2Cl2 (3). Reaction of Na2O2tBuNN‘ and YCl3 in neat pyridine gave the chloride-bridged, seven-coordinate dimer Y2(O2tBuNN‘)2(μ-Cl)2(py)2 (4). Reaction of M(CH2SiMe3)3(THF)2 (M = Sc or Y) with H2O2tBuNN‘ afforded M(O2tBuNN‘)(CH2SiMe3)(THF). The one-pot reaction of ScCl3 with Na2O2RNN‘ (R = tBu or Me) and Li[PhC(NSiMe3)2] gave the fluxional benzamidinate derivatives Sc(O2RNN‘){PhC(NSiMe3)2}. Treatment of Ti(NMe2)4 with H2O2RNN‘ gave the corresponding Ti(O2RNN‘)(NMe2)2 (R = tBu (11) or Me); 11 in turn reacts with HS-4-C6H4Me to give Ti(O2tBuNN‘)(NMe2)(S-4-C6H4Me). One-pot reactions of TiCl4(THF)2 with MeLi (2 equiv) followed by H2O2RNN‘ affords Ti(O2RNN‘)Cl2 (R = tBu (9) or Me (10)), which are cleanly methylated with MeMgBr to yield the corresponding Ti(O2RNN‘)Me2 (R = tBu (14) or Me (15)). The terminal imidotitanium compounds Ti(O2tBuNN‘)(NR)(py) (R = tBu or 2,6-C6H3Me2) were formed from the respective Ti(NR)Cl2(py)3 reagents and Na2O2tBuNN‘, and these react with CO2 by imido group transfer to yield the μ-oxo dimer Ti2(O2tBuNN‘)2(μ-O)2 (18) and RNCO. The related five-coordinate compounds Ti(O2tBuN)(NR)(py) (R = tBu, 2,6-C6H3Me2 (20) or 2,6-C6H3iPr2 (21)) were prepared in an analogous manner. These do not give identifiable metal products with CO2. Treatment of the dimethyl compounds 14 or 15 with B(ArF)3 or [CPh3][B(ArF)4] (ArF = C6F5) gave the fluxional, dimeric phenoxy-bridged cations [Ti2(O2RNN‘)2Me2]2+, which show very sluggish 1-hexene polymerization behavior. The compounds 2, 3, 4, 11, 9, 10, 16, 18, 20, and 21 have been crystallographically characterized.

Synthesis and catalytic activity of dinuclear imido titanium complexes: the molecular structure of [Ti(NPh)Cl(μ-Cl)(THF) 2] 2

Reaction of TiCl 4 with the reagents RN(SiMe 3) 2 in dichloromethane precipitates red to black powders (R = 1-adamantyl, phenyl, pentafluorophenyl, 3,5-bis(trifluoromethyl)phenyl), which on treatment with tetrahydrofuran gives the new THF adducts [Ti(NR)Cl(μ-Cl)(THF) 2] 2. The complexes are dimeric in the solid state with bridging chloride and terminal imido ligands. Activation with MAO (methylaluminoxane) gives ethene polymerisation catalysts with productivities of up to 31 kg PE [(mol complex) h bar] −1.

Influence of the structural characteristics of Ti1−xSnxO2 nanoparticles on their photocatalytic activity for the elimination of methylcyclohexane vapors

In the present work, we have used Ph3SnOH as precursor for the synthesis of highly active Ti1−xSnxO2 nanosized photocatalysts. This new preparation route is based on the reaction of TiCl4 with the organometallic compound in an organic medium to yield an amorphous precipitate of TiO2 which contains adsorbed tin species. Subsequent crystallisation of the precipitate under thermal or hydrothermal conditions determines the phase composition (rutile/anatase ratio) and the particle size of the final material. Characterisation data reveal that the incorporation of Sn promotes the anatase to rutile transformation but reduces the size of rutile crystallites. The activity of these samples has been tested for the photocatalytic oxidation of methylcyclohexane (MCH) vapors in an oxygen flow. This hydrocarbon can be considered representative of the volatile organic chemicals (VOC) present in urban atmospheres. The results obtained indicate that the Ti1−xSnxO2 materials obtained under thermal conditions present higher specific photoactivity than the reference material TiO2 P25, especially when the reaction is performed in a stream of humid oxygen. On the other hand, the comparison with undoped TiO2 prepared in similar conditions shows that the incorporation of Sn significantly increases the photocatalytic oxidation rate. High crystallinity and an adequate anatase to rutile ratio seem to be beneficial for the removal of MCH. In contrast, pure rutile Ti1−xSnxO2 nanoparticles prepared by autoclaving the amorphous precursor in HCl shows a quite limited photoactivity, despite its high surface area.

A Room-Temperature Synthesis of Titanium Nitride Hollow Spheres

Titanium nitride hollow spheres were synthesized by the reaction of TiCl4 and NaNH2 at room temperature. X-ray powder diffraction (XRD) pattern could be indexed as cubic TiN with the lattice constants of a = 4.236 A. Transmission electron microscopy (TEM) images showed hollow spheres with diameter about 200 nm. A possible formation mechanism of TiN hollow spheres was discussed.

Novel synthesis of nanocrystalline TiC hollow polyhedrons

Nanocrystalline TiC hollow polyhedrons have been prepared at 500 °C by the reaction of TiCl 4 and CaC 2. Crystalline CaC 2 particles with high melting point act not only as the reactant but also as the templates. X-ray powder diffraction indicates that the product is cubic TiC with a lattice constant a=4.314 Å. Transmission electron microscopy manifests that the polyhedrons are 30–60 nm in size. The formation mechanism of the polyhedrons is discussed.

Growth of silicon nitride whisker from polytitanosilazane

A novel process has been developed for producing silicon nitride whiskers. The process uses polytitanosilazane (PTSZ) as precursors. The precursors are prepared by reaction of TiCl 4 and silazane lithium salts. The whisker was formed by a vapor–liquid–solid mechanism and its morphology of the products was analyzed by scanning electron microscopy and its composition was determined by elemental analysis. The whiskers are about 10–100 nm in diameter, and variable lengths. The characterization of the ceramic, which was obtained from polytitanosilazane, was performed by IR, scanning electron microscope (SEM) and X-ray diffraction (XRD).

The Ti(IV) Complex of a Benzannulated N-Heterocyclic Carbene

The yellow titanium(IV) carbene complex [TiCl4(1)], 2 (1 = N,N’-bis(2,2-dimethylpropyl)benzimidazol-2-ylidene) was synthesized by reaction of TiCl4 and the benzannulated carbene 1 in toluene. The X-ray structure analysis revealed a mononuclear complex with a titanium(IV) center coordinated in a distorted trigonal-bipyramidal fashion by the carbene ligand in an equatorial position and four chloro ligands

Synthesis and Reactivity of d0Alkyl, Silyl, and Hydride Complexes of Titanium and Zirconium Featuring an Aryl-Substituted Tripodal Triamido Ligand Derived fromcis,cis-1,3,5-Triaminocyclohexane

Zirconium and titanium complexes containing the new chelating triamido ligand [cis,cis-1,3,5-(3,5-tBu2C6H3N)3C6H9]3- (1) are reported. The chloride complexes [cis,cis-1,3,5-(3,5-tBu2C6H3N)3C6H9]TiCl (2) and [cis,cis-1,3,5-(3,5-tBu2C6H3N)3C6H9]ZrCl (3) were prepared by reaction of TiCl4(THF)2 and ZrCl4, respectively, with [1]Li3 (prepared in situ). The diethyl ether adduct of 3 (3·OEt2) was crystallographically characterized. The alkyl complexes [cis,cis-1,3,5-(3,5-tBu2C6H3N)3C6H9]ZrCH2SiMe3 (4) and [cis,cis-1,3,5-(3,5-tBu2C6H3N)3C6H9]ZrCH2Ph (5) were prepared by reaction of the triamine ([1]H3) with Zr(CH2SiMe3)4 and Zr(CH2Ph)4, respectively. The aryl complexes [cis,cis-1,3,5-(3,5-tBu2C6H3N)3C6H9]ZrPh (6) and [cis,cis-1,3,5-(3,5-tBu2C6H3N)3C6H9]ZrMes (7, Mes = 2,4,6-Me3C6H2) were prepared by the reaction of 3 with PhLi and MesLi, respectively. Similarly, [cis,cis-1,3,5-(3,5-tBu2C6H3N)3C6H9]TiMe (8) was prepared by the reaction of 2 with MeMgBr. The alkyl and aryl complexes 4−8 did not react with hydrosila...

Synthesis and Structure of the First Homoleptic 1-Aza-1,3-diene Titanium Complex: A Tightrope Walk between Ligand Coordination and Ligand Coupling

The reaction of TiCl4(THF)2 or ZrCl4(THF)2 with Mg in the presence of 1-aza-1,3-dienes (1) has been investigated. Reduction of TiCl4(THF)2 with 2 equiv of Mg in the presence of 2 equiv of (R1)NCHC(R2)CH(Ph) yields the first homoleptic 1-aza-1,3-diene complex, [Ti{N(R1)CHC(R2)CH(Ph)}2] (7), but only if the 1-aza-1,3-diene is substituted by a sterically demanding group at the nitrogen atom (1b: R1 = C6H3-2,6-iPr2, R2 = H). X-ray crystallography indicates a σ2,π coordination of the heterodienes, which are reduced to 1-azabut-2-ene-1,4-diyl dianions to form folded 1-aza-2-titanacyclopent-4-ene rings. As a byproduct, the bicyclic complex [{N(R1)CHC(R2)CH(Ph)}Ti{N(R1)CHC(R2)CH(Ph)CH{C(R2)CH(Ph)}N(R1)] (8) was isolated, which is believed to arise from CN insertion of 1b into the Ti−C bond of the intermediate [{N(R1)CHC(R2)CH(Ph)}TiCl2], followed by the coordination of a further 1-aza-1,3-diene ligand. The analogous bicyclic zirconium complex [{N(R1)CHC(R2)CH(Ph)}Zr{N(R1)CHC(R2)CH(Ph)CH{C(R2)CH(Ph)}N(R1)] (6: R1 = cyclo-C6H11, R2 = Me) is the only available product when the reduction of ZrCl4(THF)2 is performed in the presence of the 1-aza-1,3-diene (cyclo-C6H11)NCHC(Me)CHPh (1a), which is substituted by a sterically less demanding group at the terminal nitrogen atom. Addition of 2 equiv of benzophenone to 7 affords the titanium complex [Ti{OCPh2CH(Ph)C(R2)CHN(R1)}2] (9). The solid-state structure of 9 shows the titanium in a distorted-tetrahedral environment, being the center of two folded oxazatitanacycloheptene rings.

Synthesis of titanium-TADDOLate complexes containing bidentate nitrogen donors and the asymmetric ethylation of benzaldehyde

Reaction of TiCl 2(TADDOLate)L 2 (L=THF ( 1) or AcOEt ( 2)) with a bidentate nitrogen-containing ligand such as 2,2 ′-bipyridine (bipy) or 1,10-phenanthroline (phen) affords six-coordinate complexes TiCl 2(TADDOLate)(L 2) (L 2=bipy ( 3) or phen ( 4)). Complexes 3 and 4 can also be obtained from reaction of 1.3 eq. of TiCl 4 with a TADDOL (α,α,α ′,α ′-tetraphenyl-1,3-dioxolane-4,5-dimethanol) ligand in diethyl ether followed by the addition of the bidentate ligand. The complex 3 reacts further with 2.2 eq. of MeLi in toluene to give the mono-methyl complex TiCl(Me)(TADDOLate)(bipy) ( 5). Complexes 3 and 4 were subjected to X-ray structural analyses and both structures reveal the same C 2 molecular symmetry with the bidentate bipy or phen ligand trans to the TADDOLate ligand. In the asymmetric reaction of diethylzinc addition to benzaldehyde, the monomeric metal complex 3 or 4 alone shows good catalytic reactivities with low to moderate enantioselectivities of 31% or 52% ee, respectively. However, with the addition of excess Ti(O- i-Pr) 4, the reaction gives nearly quantitative yields of the desired product with good enantioselectivities up to 88% ee.

A facile one-step route to nanocrystalline TiB 2 powders

Nanocrystalline titanium diboride (TiB 2) has been prepared by the reaction of TiCl 4 with NaBH 4 in the temperature range of 500–700 °C in an autoclave. X-ray powder diffraction (XRD) patterns can be indexed as hexagonal TiB 2 with the lattice constants of a=3.032 and c=3.229 Å. Transmission electron microscopy (TEM) image shows particle morphology, with average size of 15 nm for the powder obtained at 600 °C. Selected area electron diffraction (SAED) pattern confirms the prepared hexagonal TiB 2. The oxidation behavior of TiB 2 is studied by thermogravimetric analysis (TGA) and differential thermal analysis (DTA).

A novel catalyst for the glycolysis of poly(ethylene terephthalate)

AbstractPoly(ethylene terephthalate) waste materials were depolymerized by ethylene glycol (EG), diethylene glycol (DEG), and propylene glycol (PG) in the presence of a novel catalytic system: titanium (IV)‐phosphate. The new catalyst was synthesized through a reaction of TiCl4 with triethyl phosphate (C2H5O)3P(O). It was found that the depolymerization of poly(ethylene terephthalate) fiber proceeds faster in the presence of titanium (IV)‐phosphate compared with compounds traditionally used in this process like Zn(OOCCH3)2. The oligomer distribution in the glycolysis products was studied by size‐exclusion chromatography. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 1148–1152, 2003

Synthesis, Spectroscopic Properties, and Crystal Structure of the Oxonium Acid [H(OEt2)2]+[Ti2Cl9]–

The oxonium acid [H(OEt2)2]+[Ti2Cl9]− (1) was obtained by the reaction of TiCl4 with Et2O in n-pentane and subsequent partial hydrolysis. Suitable single crystals of 1 were obtained by sublimation at 5° C ([H(OEt2)2]+[Ti2Cl9]−, P212121 (no. 19), Z = 4, a = 1101.08(8), b = 1328.4(2), c = 1525.0(2) pm, T = 193(2) K, 4489 independent reflections, 197 parameters, R1 = 0.049). The cation is made up from two independent Et2O molecules and one disordered proton on two split positions. Both ether molecules exhibit a W form, and their molecular planes include an angle of 74.1(7)°. Thus a distorted tetrahedron is formed by the four methyl carbon atoms of the two ether molecules. The distance O···O amounts to 237.7(1) pm. The proton of the cation was characterized both by 1H NMR (CDCl3, T = 23 °C: δ = 11.7 ppm, w1/2 = 100 Hz) and IR spectroscopy (3120 cm−1, ν vbr). The [Ti2Cl9]− ion consists of two face sharing octahedra. 47Ti and 49Ti NMR spectra were recorded in solution (CH2Cl2, T = 23 °C: δ 49Ti = 137 ppm, w1/2 = 175 Hz; δ 47Ti = −124 ppm, w1/2 = 250 Hz). The absence of a signal for TiCl4 at δ 49Ti = 0 ppm indicates the stability of the dinuclear anion in solution.