18039-90-2Relevant articles and documents
Titanium(III) alkoxy-N-heterocyclic carbenes and a safe, low-cost route to TiCl3(THF)3
Jones, Natalie A.,Liddle, Stephen T.,Wilson, Claire,Arnold, Polly L.
, p. 755 - 757 (2008/10/09)
A new, facile method for the synthesis of [TiCl3-(THF) 3 is reported; THF extraction from the commercially widely available and cheap compound 3TiCl3·AlCl3 affords aluminum-free [TiCl3(THF)3] in excellent yield as a blue microcrystalline solid. Treatment of [TiCl3(THF)3] with 3 equiv of the potassium alkoxy carbene KL[K{OCMe2CH 2(1-C[NCHCH-NPri])}] affords the homoleptic, octahedral Ti(III) tris(carbene) complex [TiL3] in high yield, which is shown to form as the mer-isomer by a single-crystal X-ray diffraction study.
Reduction of titanium supported by a σ-/π-bonded tripyrrole ligand: Ligand C-N bond cleavage and coordination of olefin and arene with an inverse sandwich structure
Nikiforov, Grigory B.,Crewdson, Patrick,Gambarotta, Sandro,Korobkov, Ilia,Budzelaar, Peter H. M.
, p. 48 - 55 (2008/10/09)
The formally Ti(I)/Ti(II) mixed-valence toluene complex {2,5-[(C 4H3N)CPh2]2[C4H 2N(Me)]}Ti (μ,η6-C7H8)Ti[{2, 5-[(C4H3N)CPh2]2[C4H 2N(Me)]}][K(DME)2]·toluene (1) with an inverse sandwich type of structure has been obtained from the reduction of {2,5-[(C 4H3N)CPh2]2[C4H 2N(Me)]}TiCl with potassium in toluene. The bridging molecule of toluene in the paramagnetic 1 shows a visible distortion due to a substantial amount of metal-to-ring back-bonding. Complex 1 was always the only detectable product, even in cases when lower than stoichiometric amounts of reductant were employed. DFT calculations have been carried out to elucidate the electronic structure of the mixed-valence 1 in order to clarify the reason for its apparent thermodynamic stability. The most energetically favorable model comprises two divalent Ti centers connected to an organic radical anion. The olefin adducts {2,5-[(C4H3N)CPh2]2-[C 4H2N]}Ti(η2-trans-PhHC=CHPh)[K(DME)] (2) and {2,5-[(C4H3N)CPh2]2[C 4H2N (Me)]}Ti(η2-trans-PhHC=CHPh) (3) were obtained from identical reactions carried out in the presence of trans-stilbene. Complexes 2 and 3 may be regarded as the result of the oxidative addition of a transient divalent species to the trans-stilbene molecule. In the case of 2 however, the reaction is accompanied by the cleavage of the C-N bond of the π-bound alkylated pyrrole ring.
Substituent effects. Synthesis and structural characterization of group 4 metallacarboranes containing (C6H5CH2) 2C2B9H92- and [o-C 6H4(CH2)2]C2B 9H92- ligands
Kwong, Wai-Chuen,Chan, Hoi-Shan,Tang, Yong,Xie, Zuowei
, p. 4301 - 4307 (2008/10/09)
Substituants on the carborane cage carbons affect not only bonding interactions between the group 4 metal ion and the carboranyl of the C 2B9 system but also the reactivity pattern of the resulting metal complexes. Treatment of MCI4(THF)2 with 1 equiv of [(C6H5CH2)2C 2B9H9]Na2(THF),x in THF at room temperature gave the bis(carboranyl) complexes {n4:n 2-[(C6H5CH2)2C 2B9H9]2MCI(THF)}{Na(THF) 3} (M = Zr (1), Hf (2)). Under the same reaction conditions, interaction of TiCl4(THF)2 with 1 equiv of [(C 6H5CH2)2C2B 9H9]Na2(THF)x led to the isolation of a small amount of TiCl3(THF)3 and B-substituted zwitterionic compound (C6H5CH2) 2C2B9H9(THF) (4). Reaction of 1 with 1 equiv of Li[N(SiMe3)2] resulted in the replacement of a Na+ by a Li+, giving the ionic complex [n 3:n2-{(C6H5CH2) 2C2B9H9}2ZrCl-(THF)] [Li(THF)4] (3). ClZr[N(SiMe3)2]3 was isolated from the reaction of 1 with excess Li-[N(SiMe3) 2]. An equimolar reaction between M(NEt2)4 and (C6H5CH2)2B9H 11 afforded the monocarboranyl complexes [n2-(C 6H5CH2)2C2B 9H9]M(NEt2)2(NHEt2) (M = Ti (5), Zr (6)). It is believed that the additional N(p π)→M(dπ) interactions stabilize this type of complex. Treatment of MCl4(THF)2 with 1 equiv of less bulky yet rigid [{o-C6H4(CH2) 2}C2B9H9]Na2-(THF) x generated a bent-metallocene type of complex, [{o-C 6H4(CH2)2}C2B 9H9]2M(THF)2 (M = Zr (7), Hf (8)). These metallacarboranes were all fully characterized by various spectroscopic techniques and elemental analyses. Molecular structures of 1 and 3-5 were confirmed by single-crystal X-ray analyses.
The first structurally characterized nonorganometallic titanium(III) alkoxo-bridged dinuclear complexes
Utko, Jozef,Przybylak, Szymon,Jerzykiewicz, Lucian B.,Mierzwicki, Krzysztof,Latajka, Zdzislaw,Sobota, Piotr
, p. 267 - 269 (2008/10/08)
The reaction of [Ti4(OMe)14Cl2] (1) with an excess of AlMe3 gave the cocrystallite [Ti2(μ-OMe)2(μ-Cl)Cl3 (thf)3]·[Ti2(μ-OMe)3 Cl3(thf)3] (2·3) species in a 1:1 ratio. Similar to 2, [Ti2(μ-OEt)2(μ-Cl)Cl3- (thf)3] (4) was obtained in the reaction of an equimolar mixture of TiCl4 and Ti(OEt)4 with Al/AlMe3. The short distance [2.543(1)av A in 2.3 and 2.599(1) A in 4] between Ti(+3) atoms, their diamagnetism, and ELF analysis indicate the presence of a Ti-Ti bond.
Reduction-induced cyclization and redox reactions of fully methylated titanocene dichlorides bearing pendant alkenyldimethylsilyl groups, [TiCl2{η5-C5Me4(SiMe2 R)}2] (R = vinyl and allyl)
Luke?ová, Lenka,?těpni?ka, Petr,Fejfarová, Karla,Gyepes, Róbert,Císa?ová, Ivana,Horá?ek, Michal,Kubi?ta, Ji?í,Mach, Karel
, p. 2639 - 2653 (2008/10/08)
The reactions initiated by the magnesium reduction of silicon-modified titanocene dichlorides [TiCl2(η5-C5Me4SiMe2 R)2] were reported. The features in subsequent oxidative addition reactions due to the presence of the silylene groups and different lengths of the silylalkenyl groups were showed. Pendant double bonds were used as reactive functionalities for modification of the parent bent metallocene structures.
- the Wet Chemical Route to a Highly Reactive Titanium Hydride
Becker, Beate,Bogdanovic, Borislav
, p. 476 - 482 (2007/10/02)
The reaction between catalytically prepared magnesium hydride (MgH2*) and in a molar ratio of 1.5:1 in THF yields a highly pyrophoric, X-ray amorphous titanium hydride precipitate with the composition (2).This novel titanium hydride precipitate with the composition (2).This novel titanium hydride has been characterized through hydrolysis and iodolysis, as well as through thermolysis to Ti* and H2 in the solid state and in organic solvents. 2 is slightly soluble in THF and proves itself as an active reagent in a variety of reactions. - Keywords: Magnesium Hydride, Titanium Hydride, McMurry-Reaction, Titanium
x - a highly reactive titanium hydride and an active species in the McMurry reaction
Aleandri, Lorraine E.,Becke, Sigurd,Bogdanovic, Borislav,Jones, Deborah J.,Roziere, Jacques
, p. 97 - 112 (2007/10/02)
The complex reacts with catalytically-prepared solid magnesium hydride (MgH2*) or dissolved magnesium hydride (MgH'2) with evolution of hydrogen to give a highly reactive titanium hydride, x (1).The well-known low valent titanium species, obtained by reduction of TiCl3 with LiAlH4, utilized in the McMurry reaction, has been shown to be 1.An X-ray absorption spectroscopy study (EXAFS) of 1 reveals that the Ti absorber is surrounded by O (from THF) and Cl atoms plus two types of Ti neighbors.Possible structural models for 1 compatible with the EXAFS results are proposed.Complex 1 is an active reagent for the coupling reaction of benzophenone to give tetraphenylethene.During the reaction hydrogen is liberated and the inorganic side product has been shown to be titanium(III) oxychloride; thus the McMurry reaction employing 1 as the reagent can be described by . On the basis of these results, a new interpretation of the mechanism for the McMurry reaction is presented.Complex 1 also undergoes a number of carbenoid type reactions, which may proceed via a "titanium carbenoid" intermediate 9a-c. Key words: Titanium; Hydride; Magnesium; EXAFS
Mono-η-cycloheptatrienyltitanium Chemistry: Synthesis. Molecular and Electronic Structures, and Reactivity of the Complexes (L = Tertiary Phosphine, O- or N-donor Ligand; X = Cl or Alkyl)
Davies, Cathryn E.,Gardiner, Ian M.,Green, Jennifer C.,Green, Malcolm, L. H.,Hazel, Nicholas, J.,et al.
, p. 669 - 684 (2007/10/02)
Bis(η-toluene)titanium reacts with cycloheptatriene in the presence of (AlEtCl2)2 at >60 deg C to form and at room temperature 2> (thf = tetrahydrofuran) is also formed.The crystal structure of the latter has b
Reductive Preparation of Bis(arene)metal Complexes from Metal Halides in Solution using Potassium Atoms
Hawker, Pelham N.,Timms, Peter L.
, p. 1123 - 1126 (2007/10/02)
Some known bis(arene) complexes of zerovalent Ti, V, Cr and Mo have been synthesised in a new way by stepwise reduction of solutions of the metal chlorides in tetrahydrofuran and arene, using K atoms condensed into the solutions at -110 deg C under vacuum in a rotary reactor.The extent of reduction was followed by observing colour changes in the solutions.With Ti and V, the initial products were anionic forms of the bis(arene) complexes, which were oxidised to give the zerovalent compounds.The method is a useful way of making 0.1-1 g samples of some bis(arene)titanium complexes and bis(naphthalene) complexes of V, Cr, and Mo which are otherwise accessible only by using the transition-metal atoms as reagents.
