- Synthesis and molecular structure of titanium complexes containing a reduced TEMPO radical
-
Two titanium compounds containing monoanionic ligands derived from TEMPO were synthesized and structurally characterized, demonstrating the flexibility of the coordination modes adopted by the ligand.
- Mahanthappa, Mahesh K.,Huang, Kuo-Wei,Cole, Adam P.,Waymouth, Robert M.
-
-
Read Online
- ELECTRONIC TRANSITIONS IN alpha - AND beta -TITANIUM TRICHLORIDE.
-
The reflectance spectrum of alpha -TiCl//3 has been investigated in the range of photon energy between 1. 8 and 10. 4 ev. The optical constants have been obtained by a Kramers-Kronig analysis of the near normal incidence reflectance. The absorption spectrum of beta -TiCl//3 crystalline films in the same energy region is presented. The results are interpreted by means of a model containing both localized and one-electron band states. The low energy peaks of alpha - and beta -TiCl//3 (between 2 and 4 ev) are assigned to localized interionic transitions between d states of neighboring Ti ions. The strong bands beyond 4 ev are ascribed to charge transfer and band-to-band transitions. It is suggested that the interband gap between the anion 3p and the cation 4s bands is around 7. 5 ev in alpha -TiCl//3 and 6. 9 ev in beta -TiCl//3.
- Pollini
-
-
Read Online
- DETERMINATION OF STRUCTURES OF MOLECULES OF LOWER HALIDES OF TRANSITION ELEMENTS BY GAS ELECTRON-DIFFRACTION ANALYSIS. I. TITANIUM TRICHLORIDE
-
A method for the electron-diffraction investigation of unstable halides of transition elements with lower valences is described.The relative pressures of TiCl4, TiCl3, TiCl2, and TiCl vapors in the TiCl4 + Ti system at 400-2000 deg K were calculated.Electron-diffraction patterns of gaseous TiCl3 at 1100 deg K were obtained.The effective geometrical and vibrational parameters of the TiCl3 molecule were determined.The equilibrium structure with D3h symmetry was found within the harmonic approximation, and the vibrational frequencies and force constants were evaluated.
- Mamaeva, G. I.,Romanov, G. V.,Spiridonov, V. P.,Troyanov, S. I.
-
-
Read Online
- Reduction of dinitrobenzenes by electron-carrying catalysts in the electrosynthesis of diaminobenzenes
-
The interaction of isomeric dinitrobenzenes (DNBs) with titanium(III), tin(II), and vanadium(II) chlorides, which are reducing agents used as electron carriers in the electrosynthesis of diaminobenzenes, has been studied. Rate constants of the reduction of isomeric DNBs and nitrophenylhydroxylamines by SnCl2 and TiCl3 in a 2 M water-alcohol solution (10 vol.% C2H5OH) of HCl were measured, and activation energies of the reduction of isomeric DNBs were determined. The rates of interaction of DNBs with the listed mediators increase in the series SnCl2 3 2. It is shown that the electrolysis of DNBs in the presence of an excess of these mediators makes it possible to obtain the corresponding diaminobenzenes with a yield of 60–90%.
- Abakumov, M. V.,Leonova, M. Yu.,Mikhalchenko, L. V.,Novikov, V. T.,Zaplavin, A. P.
-
p. 1927 - 1933
(2021/11/05)
-
- Fundamental study on synthesis and enrichment of titanium subchloride
-
In order to establish a new high-speed/(semi-)continuous titanium production process based on the magnesiothermic reduction of titanium subchlorides (subhalide reduction process), a novel synthetic process for obtaining titanium subchlorides (TiClx, x = 2, 3) by the reaction of titanium tetrachloride (TiCl4) with titanium metal at 1273 K was investigated. It was demonstrated that the efficiency of the TiClx formation improved drastically when molten salts were used as the reaction medium as compared with that of the synthesis by employing the direct reaction of TiCl4 gas with solid titanium. The feasibility of the enrichment process of TiClx in molten salt was also demonstrated. The method for producing the titanium subchlorides investigated in this study can be applied to the new high-speed production process of titanium.
- Takeda, Osamu,Okabe, Toru H.
-
p. 376 - 383
(2009/02/01)
-
- Redox reactions with bis(η6-arene) derivatives of early transition metals
-
The reactivity of M(η6-arene)2 derivatives of early transition metals (M = Ti, Cr, Mo, arene = MeC6H5; M = V, Nb, arene = 1,3,5-Me3C6H3) has been investigated and the syntheses of new and known compounds are described. The derivatives M(CH3COO)3, M = Ti, V, Nb, Cr; M(CF 3COO)3, M = Ti, Nb, Cr; M(acac)3, M = Ti, V, Mo, acac = acetylacetonato, and M(F6acac)3, F 6acac = hexafluoroacetylacetonato, M = V, Nb have been prepared by reaction of the metal bis(arene) derivatives with the appropriate Lewis acid. The crystal and molecular structure of V(F6acac)3 has been determined. Hydrogen halides or halogens react with M(η6-arene) 2 with formation of metal halides, a highly reactive form of VCl 3 being obtained from V(η6-1,3,5-Me3C 6H3)2 and hydrogen chloride in heptane. TiCl4 oxidizes Ti(η6-arene)2 with complete loss of the arene ligands. An electron transfer process affording ionic derivatives of formula [M(η6-MeC6H5) 2][TiCl4(THF)2], M = Cr (structurally characterized), Mo, has been observed between the THF-adduct of TiCl4 and the appropriate metal-arene derivative of Group 6.
- Calderazzo, Fausto,Englert, Ulli,Pampaloni, Guido,Volpe, Manuel
-
p. 3321 - 3332
(2007/10/03)
-
- Change in regioselectivity in the monoreduction of 2,4,6-trinitrotoluene with titanium(III) and vanadium(II) ions in the presence of iron(II) and copper(II) salts
-
Small additives of iron(II) or copper(II) salts change the regioselectivity of 2,4,6-trinitrotoluene monoreduction with titanium(III) chloride affording predominantly less accessible 2-amino-4,6-dinitrotoluene over 4-amino-2,6-dinitrotoluene (from 25% when the reduction occurs in the absence of the iron and copper salts to 70% in the presence of these salts). A possible mechanism of the process is discussed.
- Leibzon,Michalchenko,Leonova,Gultyai
-
p. 1203 - 1207
(2007/10/03)
-
- Solid state metathesis reactions in various applications
-
Solid state metathesis reactions have been studied in fused silica tubes, by differential thermal analysis, and by X-ray powder diffraction. A selection of reactions between metal (La, Nb, and Ni) chlorides and lithium nitride or lithium acetylide were investigated to get more insight into reaction pathways and intermediate reaction stages that may be adopted on course of the formation of metal nitrides or carbides. Intermediate compounds are considered to be important because they can control the reactivity of a system. Such compounds were traced by changing the molar ratios of reaction partners away from the salt-balanced binary metal nitride or carbide target compositions. New preparative perspectives are discovered when metal chlorides were reacted with lithium nitridoborate or lithium cyanamide. Due to their reductive nature towards several d-block metal chlorides, (BN2)3- and (CN2)2- react to form metals or metal nitrides plus X-ray amorphous BN, and probably C3N4. With lanthanum chloride they can react to form nitridoborates and nitridocarbonates. The metathesis reaction between lithium cyanamide and cyanuric chloride (C3N 3Cl3) instead of metal chloride was studied for the synthesis of C3N4.
- Gibson, Katharina,Stroebele, Markus,Blaschkowski, Bjoern,Glaser, Jochen,Weisser, Martina,Srinivasan, Radhakrishnan,Kolb, Heinz-Juergen,Meyer, Hans-Juergen
-
p. 1863 - 1870
(2008/10/08)
-
- Synthesis and reactivity of cyclopentadienyl and indenyl ligands bearing ω-fluorinated pendant groups. Crystal structure of (ortho-F-C6H4)-CPh2-C5H 4SiMe3
-
A series of cyclopentadienes and indenes with ω-fluorinated pendant groups have been synthesised and their reactivity towards metallating agents n-BuLi, NaH, TIOEt, Me3SiCl, Me3SnCl, TiHal4, ZrX4 (X = Cl, NMe2) has been investigated. The crystal structure of 1-trimethylsilyl-3-(diphenyl-ortho-fluorophenyl-methyl)-cyclopentadiene (3) was determined.
- Khvorost,Lemenovskii,Ustynyuk,Rufanov,Kipke
-
p. 1207 - 1214
(2007/10/03)
-
- Crystal Structures of Transition-Metal Halides TiCl4, α-TiCl3, WCl4, and TiI2
-
The crystal structures of halides TiCl4, α-TiCl3 (low-temperature modification), WCl4, and TiI2 are determined. The crystals of TiCl4 are built of tetrahedral molecules with Ti-Cl distances of 2.156-2.172 A?. The phase transition in the three-layered modification α-TiCl3 below 220 K is accompanied by the distortion of the symmetry to triclinic and formation of the Ti?Ti pairs spaced by 3.43 A?. The structure of WCl4 contains linear chains of WCl6 octahedra that share opposite edges with the distances of 2.69 A? in the W-W pairs. In the layered structure of TiI2, the titanium atoms occupy the octahedral cavities in the two-layer packing of iodine atoms with a Ti-I distance of 2.903 A?.
- Troyanov,Snigireva
-
p. 580 - 585
(2008/10/08)
-
- Kinetics Study of Propene Polymerization with Porous Titanium Trichloride
-
Two types of high performance porous titanium trichloride catalysts wereprepared. One catalyst (Catalyst A) was converted from the solid obtain ed by the reduction of titanium tetrachloride with alkylaluminum followed by the treatment with dibuthyl ether and hexachloroethane. The other catalyst (Catalyst B) was prepared from the solid reduced from titanium tetrachloride with alkylaluminum by treating with ether and titanium tetrachloride successively. The kinetics of propene polymerization with these two catalysts were studied and these catalysts compared with ball-milled titanium trichloride catalyst (AA-type titanium trichloride catalyst). Though the properties of polymerization sites on these three types of catalysts are almost the same, the polymerization sites on high performance catalysts were about ten times that on AA-type titanium trichloride catalyst. As a result, porous titanium trichloride catalysts showed higher activities than AA-type titanium trichloride catalyst. Catalyst B suffered from a more significant decrease in activity than Catalyst A. Thisseems to be due to TiCl4 which remains in catalyst B and causes deactiv ation of polymerization sites.
- Ueno, Hiroshi,Imanishi, Kunihiko,Ueki, Satoshi,Kohara, Tadanao
-
-
- Preparation and surface science characterization of model Ziegler-Natta catalysts. Role of undercoordinated surface magnesium atoms in the chemisorption of TiCl4 on MgCl2 thin films
-
Two new synthetic routes for the preparation of model Ziegler-Natta catalysts under UHV conditions are described. The exposure of metallic magnesium to TiCl4 produced titanium chloride films with Ti in the 4+, 3+, 2+, and 0 oxidation states. Stable titanium chloride films could also be obtained by TiCl4 and Mg codeposition on MgCl2 and Au. A TiCl4/TiCl2 film was obtained in this case. The reaction of these systems with AlEt3 produced model catalysts for the polymerization of both ethylene and propylene. XPS is a proper technique for the characterization of the oxidation state of Ti in a variety of titanium chloride surface species. The stability of MgCl2 surfaces with a high concentration of undercoordinated Mg atoms was studied in UHV by Mg gas-phase deposition on a MgCl2 multilayer film. The Mg adatoms were readily coordinated by the Cl ions diffusing from the halide bulk to the surface. Mg-containing MgCl2 faces are thermodynamically unstable, and the fast diffusion of the Cl ions in the MgCl2 matrix allows the recovery of the chlorine termination to lower the system surface energy. The high mobility of the chlorine ions is of central importance for the molecular level understanding of the dynamic equilibrium among the MgCl2 surface, TiCl4, and the electron donors used in the synthesis of high performance microporous Ziegler-Natta catalysts. The deposition of MgCl2 in the presence of TiCl4 was studied for the stabilization of high Miller index faces during the MgCl2 film growth. The interaction between the two halides is too weak to influence the MgCl2 deposition, and TiCl4 could not be chemisorbed at 300 K.
- Magni, Enrico,Somorjai, Gabor A.
-
p. 8788 - 8795
(2007/10/03)
-
- Influences of Nuclear Mass, Size, Shape and Spin on Chemical Isotope Effect of Titanium
-
Titanium isotopes of Ti (III) or Ti (IV) were fractionated by liquid-liquid extraction system using dicyciohexano-18-crown-6. The nuclear size and shape effect and the nucicar spin effect resulted in the breakdowns of the linear dependency of the enrichment factors to the mass difference. The nuclear mass effect, the nuclear size and shape effect and the nucicar spin effect were calculated by the isotope pair evaluation method. The nuclear mass effects were O.OOO634 for 48-46Ti(111) and 0.000559 for 48Ti-46Ti (IV). where the total enrichment factor were 0.000989 and -0.000166, respectively. The nuclear size and shape effects were O.000356 for anc -0.000725 for 46Ti-46Ti(IV). The nuclear spin effects were 0.000180 for 47Ti(III), 0.000369 for 49Ti (III), -0.000303 for 47Ti (IV) and -0.000526 for 49H (IV). The ratio of chemical effect given by the field shift of 3d-orbital to that of 4s-orhital was -1.54. which had same direction and quantity with the field shift ratio of 3d-orbital to 4s-orbitai in Ti 1 in atomic spectra. This showed that the nuclear size and shape effect on the chemical isotope effect directly reflected the field shifts of Ti 1. The nucicar spin effect was the function of the number of the hyperfine splitting vihrational energy leveis and the coordination number. This effect was found when the coordination numbers differ nonstoichiometrically between the aqueous phase and the organic phase. WILEY-VCH Verlag GmbH. 1998.
- Fujii, Toshyuki,Inagawa, Jim,Nishixawa, Kazushige
-
p. 1880 - 1885
(2008/10/08)
-
- Shock tube study of the reaction of H atoms with TiCl4
-
The reaction of H atoms with TiCl4 was studied behind reflected shock waves at temperatures between 1190 and 1500 K and pressures around 1.5 bar by applying atomic resonance absorption spectrometry for time-resolved measurements of H atoms at the Lα line. The thermal decomposition of ethyl iodide (C2H5I) served as the H atom source. By using a high excess of TiCl4, the consumption of H could be modeled by pseudo first-order kinetics. For the reaction TiCl4 + H → TiCl3 + HCl a temperature-independent rate coefficient of k1 = 3.5 ± 0.9 × 1013 cm3 mol-1 s-1 was found for the temperature range of the present experiments.
- Herzler,Roth
-
p. 9341 - 9343
(2007/10/03)
-
- Gaseous Species in the Ti-Al-Cl System and Reaction with H2O
-
Chemical species in the Ti-Al-Cl system at elevated temperatures were studied by effusion-beam mass spectrometry up to 1400 K.Gaseous TiAlCl5 and TiAlCl6 were identified as products of the reaction of TiCl4(g) and a Ti-Al mixture above about 900 K, for which AlCl3, TiCl2, and TiCl3 were also present.No evidence was found for TiAlCl7.When gaseous TiCl4, AlCl3, and H2O and admitted simultaneously, TiOCl2, Al(OH)Cl2, and TiAl(OH)Cl5 were observed.All ion species showed the correct isotopic distribution.The results confirm earlier indications that AlCl3 forms gaseous complexes with divalent and trivalent Ti, but not with tetravalent Ti.
- Hildenbrand, D. L.,Lau, K. H.
-
p. 3435 - 3437
(2007/10/02)
-
- LASER-INDUCED VAPOUR-PHASE SYNTHESES OF BORON AND TITANIUM DIBORIDE POWDERS.
-
Small diameter boron and titanium diboride powders were synthesized from vapor phase reactants heated with infrared radiation from a Co//2 laser. Boron powders were synthesized from BCl//3 plus H//2 gas mixtures from B//2H//6. TiCl//4 plus B//2H//6 gas mixtures yielded TiB//2 powder. BCl//3 plus H//2 plus TiCl//4 gas mixtures yielded TiCl//3 powder but no TiB//2. Novel equipment designed to vaporize TiCl//4 liquid is described. Detailed characterizations of the product powders are presented.
- Casey,Haggerty
-
p. 737 - 744
(2008/10/08)
-
- Sequence distribution of aluminum(3+) and titanium(3+) ions in β-phase (TiCl3)(AlCl3)0.33
-
For the first time, the sequence distribution concepts applied for understanding organic copolymer microstructures are used to determine the microstructure of an inorganic copolymer, β-(TiCl3)(AlCl3)0.33, consisting of TiCl3 and AlCl3 sequences or repeat units. Whereas organic copolymer sequence distributions are invariably determined from interpretation of 13C NMR spectra, we have determined the TiCl3, AlCl3 sequence distributions in this inorganic copolymer by magnetic methods (electron spin resonance spectroscopy and magnetic susceptibility) sensitive to unpaired electrons. The magnetic behavior of this material is consistent with a periodic sequence distribution in which Al3+ and Ti3+ ions have fixed, alternating runs of one and three units, respectively. This sequence distribution gives rise to 0.33 spin/Ti. Other sequence distributions that have longer Al3+ and/or Ti3+ runs and give rise to only 0-0.20 spin/Ti can be discounted.
- Brant, Patrick,Tornqvist, Erik G. M.
-
p. 3776 - 3779
(2008/10/08)
-
- Jahn-Teller effect of Ti3+ in octahedral coordination: A spectroscopic study of TiCl63- complexes
-
Compounds A2A′TiCl6 (A, A′ = alkali-metal ions) with cubic elpasolite structures have been investigated by means of ligand field, EPR, and Raman spectroscopy as well as susceptibility measurements and structural methods with respect to the Jahn-Teller instability of the octahedral 2T2g ground state. A strong dynamic coupling of the vibrational ε mode of the TiCl63- octahedra with this state is derived from the EPR data (EJT ≈ 400 cm-1). Though the Ti3+ concentration is very large, no indication of a cooperative effect with a dynamic to static transition has been found down to 4.2 K. The phase transitions at 210 and 155 K for A, A′ = Cs, K and Rb, Na, respectively, are caused by geometric packing forces and induce a tiny tetragonal distortion of the TiCl63- octahedra (D4h compression), which superimposes on the otherwise dominating dynamic Jahn-Teller coupling. The splitting of the excited 2Eg state in the ligand field spectra is also due to the ε mode. The vibronic interaction is much larger in this case (EJT ≈; 1800 cm-1), because the 2Eg state is σ antibonding and hence more strongly coupled to the ligand environment than the only π-antibonding 2T2g ground state.
- Ameis,Kremer,Reinen
-
p. 2751 - 2754
(2008/10/08)
-
