Reaction Of TiCl4 Research Articles

Syntheses, Characterization, and Ethylene Polymerization of Titanium Complexes with Double-Duty Tridentate [ONN] Ligands

A series of titanium complexes containing the tridentate [ONN] ligands La–Lf were synthesized and characterized. The ligands Lb (8-quinolinolato-CH2NHAr; Ar = 2,6-diisopropylphenyl) has been prepared by the reduction of the corresponding imino-quinolinol compound La(8-quinolinolato-CH═NAr; Ar = 2,6-diisopropylphenyl) with LiAlH4 in high yield. Ligands Lc–Lf were synthesized by a procedure similar to that used to prepare ligand Lb. Reaction of TiCl4 with imino-quinolinol ligand La affords the six-coordinate trichloride titanium complex 1. The selective synthesis of tri- and dichlorotitanium complexes containing ligand Lb was achieved by changing the base for deprotonation. When it is deprotonated by NaH, ligand Lb can be used as a tridentate monoanionic ligand to synthesize trichlorotitanium complex 2. While deprotonated by nBuLi, it can be used as a tridentate dianionic ligand to synthesize dichlorotitanium complex 3. Other dichlorotitanium complexes 4–7 were synthesized by a procedure similar to that used to prepare complex 3. All complexes have been characterized by 1H NMR spectra and elemental analysis. The molecular structures of ligand Lb and complex 1 have been characterized by single-crystal X-ray diffraction analyses. XANES and EXAFS spectroscopy performed on the representative complexes 2 and 3 reveals the different coordination geometries. When they are activated by excess methylaluminoxane (MAO), all of the titanium complexes can be used as catalysts for ethylene polymerization and exhibit moderate to good activities. It was found that the catalytic behaviors of the title complexes were highly affected by the coordination entironment of the metal center and the effect of substituent groups on ligands.

Highly Active Ethylene Polymerization and Regioselective 1-Hexene Oligomerization Using Zirconium and Titanium Catalysts with Tridentate [ONO] Ligands

A series of tridentate dianionic ligands [4-(t)Bu-6-R-2-(3-R'-5-(t)Bu-2-OC(6)H(2))N=CH C(6)H(2)O](2-) (L) [R = R' = (t)Bu (L1); R = CMe(2)Ph, R' = (t)Bu (L2); R = adamantyl, R' = (t)Bu (L3); R = R' = CMe(2)Ph (L4); R = SiMe(2)(t)Bu, R' = CMe(2)Ph (L5)] were synthesized. Reactions of TiCl(4) with 1 equiv of ligands L1-L5 in toluene afford five-coordinate titanium complexes with general formula LTiCl(2) [L = L1 (1); L2 (2); L3 (3); L4 (4); L5 (5)]. The addition of tetrahydrofuran (THF) to titanium complex 5 readily gives THF-solvated six-coordinate complex 6, which also was obtained by reaction of TiCl(4) with 1 equiv of ligand L5 in THF. Reactions of ZrCl(4) with 1 or 2 equiv of ligands L1-L5 afford six-coordinate zirconium mono(ligand) complexes LZrCl(2)(THF) [L = L2 (7); L4 (8); L5 (9)], and bis(ligand) complexes L(2)Zr [L = L1 (10); L4 (11)]. The molecular structures of complexes 2, 8, and 11 were established by single-crystal X-ray diffraction studies. Upon activation with methylaluminoxane, complexes 1-9 are active for ethylene polymerization. The activities and half-lifes of the catalyst systems based on zirconium complexes are more than 10(6) g of polyethylene (mol Zr)(-1) h(-1) and 6 h, respectively. Complex 9 is more active and long-lived, with a turnover frequency (TOF) of 2.6 × 10(5) (mol C(2)H(4)) (mol Zr)(-1) h(-1), a half-life of >16 h, and a total turnover number (TON) of more than 10(6) (mol C(2)H(4)) (mol Zr)(-1) at 20 °C and 0.5 MPa pressure. Even at 80 °C, complex 9/MAO catalyst system has a long lifetime (t(1/2) > 2 h), as well as high activity that is comparable with that at 20 °C. When activated with methylaluminoxane (MAO), complex 9 also show moderate catalytic activity and more than 99% 2,1-regioselectivity for 1-hexene oligomerization.

Oxide Removal and Selective Etching of In from InSb(100) with TiCl4

The reaction of TiCl4 with a native oxide-covered InSb(100) film grown epitaxially on GaAs(100) was investigated using X-ray photoelectron spectroscopy, scanning electron microscopy, and atomic force microscopy. At room temperature and low pressure (∼3 × 10–7 Torr), TiCl4 reacted with In and Sb oxides, producing a stable indium chloride overlayer and removing a small amount of Sb, likely as SbCl3, after a subsequent vacuum annealing step at 500 K. About 25% of the O was removed, likely as TiOCl2, and a submonolayer of TiO2 was deposited, which competed with oxide etching. When TiCl4 was dosed with the substrate temperature maintained at 470–560 K, the etching reaction prevailed, resulting in complete removal of the native oxide without depositing TiO2. Heating alone could not account for the results because the oxide desorption onset was 550 K and some oxide was present even after annealing in vacuum to 650 K. TiCl4 exposure at elevated temperatures not only removed the native oxide but also preferentially etched substrate In atoms by forming volatile indium chlorides. Residual indium chlorides remained on the surface in the 470–530 K range but were completely removed at 500–560 K. The depletion of In from the surface promoted the out-diffusion of In from the substrate, allowing bulk etching and accumulation of at least a 72 Å thick Sb layer. Accumulation of Sb on the surface is consistent with a higher kinetic barrier for chlorination of Sb compared to In. The atomic ratio of Ti to Sb in elemental states was 0.43–0.46, suggesting TiSb2 alloy formation. Surface height modulations on the order of 100 nm and the presence of pits and grain boundaries were observed.

Surface reactions of TiCl4 and Al(CH3)3 on GaAs(100) during the first half-cycle of atomic layer deposition

GaAs(100) was exposed to pulses of trimethylaluminum (TMA, Al(CH3)3) and titanium tetrachloride (TiCl4) to mimic the first half-cycle of atomic layer deposition (ALD). Both precursors removed the 9.0±1.6Å-thick mixed oxide consisting primarily of As2O3 with a small Ga2O component that was left on the surface after aqueous HF treatment and vacuum annealing. In its place, TMA deposited an Al2O3 layer, but TiCl4 exposure left Cl atoms adsorbed to an elemental As layer. This suggests that oxygen was removed by the formation of a volatile oxychloride species. A small TiO2 coverage of approximately 0.04 monolayer remained on the surface for deposition temperatures of 89°C to 135°C, but no TiO2 was present from 170°C to 230°C. The adsorbed Cl layer chemically passivated the surface at these temperatures and blocked TiO2 deposition even after 50 full ALD cycles of TiCl4 and water vapor. The Cl and As layers desorbed simultaneously at higher temperature producing peaks in the temperature programmed desorption spectrum in the range 237–297°C. This allowed TiO2 deposition at 300°C in single TiCl4 pulse experiments. On the native oxide-covered surface where there was a higher proportional Ga oxide composition, TiCl4 exposure deposited TiO2.

Synthesis and structures of adamantyl-substituted constrained geometry cyclopentadienyl–phenoxytitanium complexes and their catalytic properties for olefin polymerization

A number of new constrained geometry titanium complexes, [η 5: η 1-2-C 5Me 4-4-R-6-Ad-C 6H 2O]TiCl 2 [Ad = adamantyl, R = Me ( 8), t Bu ( 9)] and [η 5: η 1-C 5H 2Ph 2-4- t Bu-6-Ad-C 6H 2O]TiCl 2 ( 10), were synthesized from reactions of TiCl 4 either directly with corresponding free ligands, 2-C 5Me 4H-4-R-6-Ad-C 6H 2OH [R = Me ( 5), t Bu ( 6)], or with the dilithium salt of the free ligand 2-C 5H 3Ph 2-4- t Bu-6-Ad-C 6H 2OH ( 7). These new titanium complexes were fully characterized by 1H and 13C NMR spectroscopy and elemental analyses, and the molecular structures of 8 and 9 were determined by single-crystal X-ray crystallography. Upon activation with Al i Bu 3 and Ph 3CB(C 6F 5) 4 (TIBA/B), these complexes exhibit high catalytic activity for 5-ethylidene-2-norbornene (ENB) polymerization as well as ethylene/1-hexene and ethylene/ENB copolymerization with good tacticity-control ability for the ENB polymerization and high comonomer incorporation ability for the copolymerization reactions. It was found that the bulky adamantyl substituent at the ortho position of the phenoxy group in the ligands of these complexes apparently influences the molecular weight and the microstructure of the resultant polymers.

Syntheses, reactions, and ethylene polymerization of titanium complexes with [N,N,S] ligands

Tridentate dianionic arylsulfide free ligands [ArNHCH(2)C(6)H(4)NHC(6)H(4)-2-SPh] (Ar = Ph (3a); Ar = 2,4,6-trimethylphenyl (3b); Ar = 2,6-diisopropylphenyl (3c)) have been prepared by reduction of the corresponding imine compounds [ArN[double bond, length as m-dash]CHC(6)H(4)NHC(6)H(4)-2-SPh] (Ar = Ph (2a); Ar = 2,4,6-trimethylphenyl (2b); Ar = 2,6-diisopropylphenyl (2c)) with LiAlH(4) in high yields. Reactions of TiCl(4) with the tridentate dianionic arylsulfide free ligands (3a-3c) afford five-coordinate and four-coordinate titanium complexes [κS, κ(2)N-(ArNHCH(2)C(6)H(4)NHC(6)H(4)-2-SPh)TiCl(2)] (Ar = Ph (4a); Ar = 2,4,6-trimethylphenyl (4b)] and [κ(2)N-(ArNHCH(2)C(6)H(4)NHC(6)H(4)-2-SPh)TiCl(2)] (Ar = 2,6-diisopropylphenyl (4c)], respectively. The molecular structures of compounds 2b, 2c, 3b and 3c·HCl have been characterized by single crystal X-ray diffraction analyses. Complexes 2a-4c are characterized by IR,(1)H-NMR spectra, and elemental analysis. EXAFS spectroscopy performed on complexes 4b and 4c reveals the expected different coordination geometry due to steric hindrance effect. When activated by excess methylaluminoxane (MAO), 4a-4c can be used as catalysts for ethylene polymerization and exhibit moderate to good activities.

New Titanium Complexes with Symmetric or Asymmetric cis-9,10-Dihydrophenanthrenediamide Ligands Formed through Sequential Intramolecular C−C Bond-Forming Reactions

A series of new titanium(IV) complexes with symmetric or asymmetric cis-9,10-dihydrophenanthrenediamide ligands, cis-9,10-PhenH(2)(NR)(2)Ti(O(i)Pr)(2) [PhenH(2) = 9,10-dihydrophenanthrene, R = 2,6-(i)Pr(2)C(6)H(3) (2a), 2,6-Et(2)C(6)H(3) (2b), 2,6-Me(2)C(6)H(3) (2c)], cis-9,10-PhenH(2)(NR(1))(NR(2))Ti(O(i)Pr)(2) [R(1) = 2,6-(i)Pr(2)C(6)H(3), R(2) = 2,6-Et(2)C(6)H(3) (2d); R(1) = 2,6-(i)Pr(2)C(6)H(3), R(2) = 2,6-Me(2)C(6)H(3) (2e)], and [cis-9,10-PhenH(2)(NR(1))(2)][o-C(6)H(4)(CH=NR(2))]TiO(i)Pr [R(1) = 2,6-(i)Pr(2)C(6)H(3), R(2) = 2,6-Et(2)C(6)H(3) (3a); R(1) = 2,6-(i)Pr(2)C(6)H(3), 2,6-Me(2)C(6)H(3) (3b)], have been synthesized from the reactions of TiCl(2)(O(i)Pr)(2) with o-C(6)H(4)(CH=NR)Li [R = 2,6-(i)Pr(2)C(6)H(3), 2,6-Et(2)C(6)H(3), 2,6-Me(2)C(6)H(3)]. The symmetric complexes 2a-2c were obtained from the reactions of TiCl(2)(O(i)Pr)(2) with 2 equiv of the corresponding o-C(6)H(4)(CH=NR)Li followed by intramolecular C-C bond-forming reductive elimination and oxidative coupling processes, while the asymmetric complexes 2d-2e were formed from the reaction of TiCl(2)(O(i)Pr)(2) with two different types of o-C(6)H(4)(CH=NR)Li sequentially. The complexes 3a and 3b were also isolated from the reactions for complexes 2d and 2e. All complexes were characterized by (1)H and (13)C NMR spectroscopy, and the molecular structures of 2a, 2b, 2e, and 3a were determined by X-ray crystallography.

Easy and Selective Method for the Synthesis of Various Mono-O-functionalized Calix[4]arenes: De-O-functionalization Using TiCl4

An efficient and selective method for the monofunctionalization of p-tert-butylcalix[4]arene is described. A mono-de-O-functionalization of disubstituted p-tert-butylcalix[4]arenes using titanium tetrachloride was developed to synthesize a series of monosubstituted p-tert-butylcalix[4]arenes with the pendant functions being ethoxycarbonylmethyloxy, 3-ethoxycarbonylpropyloxy, cyanomethyloxy, 3-cyanopropyloxy, 4-bromobutyloxy, 3-hydroxypropyloxy, propyloxy, 2-methylpropyloxy, 3-butynyloxy, and 3-cyanopropyloxy groups. The reaction mechanism of the formation of 5,11,17,23-tetra-tert-butyl-26,27,28-trihydroxy-25-(3-ethoxycarbonylpropyloxy) calix[4]arene was studied by (1)H NMR and GC/mass spectroscopy monitoring. Reaction of TiCl4 with the disubstituted p-tert-butylcalix[4]arene produced the corresponding dioxocalix[4]arene titanium dichloride complex, which undergoes elimination of ethyl 4-chlorobutyrate, leading to a trioxocalix[4]arene titanium dichloride complex and to monosubstituted calix[4]arene after hydrolysis. These two complexes were also synthesized, isolated, and fully characterized.

ChemInform Abstract: Reductive Coupling of Aromatic Aldehydes and Imines by the Low Valent Titanium Species Generated in the Reaction of TiCl4 with Et3N.

Abstract Aromatic aldehydes and imines are converted to the corresponding diols and diamines using the low valent titanium species generated by the reaction of TiCl 4 with triethylamine.

Direct Synthesis of Titanium Complexes with Chelating cis‐9,10‐Dihydrophenanthrenediamide Ligands through Sequential CC Bond‐Forming Reactions from o‐Metalated Arylimines

A series of new titanium(IV) complexes with o-metalated arylimine and/or cis-9,10-dihydrophenanthrenediamide ligands, [o-C(6)H(4)(CH=NR)TiCl(3)] (R=2,6-iPr(2)C(6)H(3) (3 a), 2,6-Me(2)C(6)H(3) (3 b), tBu (3 c)), [cis-9,10-PhenH(2)(NR)(2)TiCl(2)] (PhenH(2)=9,10-dihydrophenanthrene; R=2,6-iPr(2)C(6)H(3) (4 a), 2,6-Me(2)C(6)H(3) (4 b), tBu (4 c)), [{cis-9,10-PhenH(2)(NR)(2)}{o-C(6)H(4)(HC=NR)}TiCl] (R=2,6-iPr(2)C(6)H(3) (5 a), 2,6-Me(2)C(6)H(3) (5 b), tBu (5 c)), have been synthesised from the reactions of TiCl(4) with o-C(6)H(4)(CH=NR)Li (R=2,6-iPr(2)C(6)H(3), 2,6-Me(2)C(6)H(3), tBu). Complexes 4 and 5 were formed unexpectedly from the reactions of TiCl(4) with two or three equivalents of the corresponding o-C(6)H(4)(CH=NR)Li followed by sequential intramolecular C-C bond-forming reductive elimination and oxidative coupling reactions. Attempts to isolate the intermediates, [{o-C(6)H(4)(CH=NR)}(2)TiCl(2)] (2), were unsuccessful. All complexes were characterised by (1)H and (13)C NMR spectroscopy, and the molecular structures of 3 a, 4 a-c, 5 a, and 5 c were determined by X-ray crystallography.

Syntheses, X-ray structures and CVD of titanium(iv) arsine complexes

Five titanium arsine compounds have been synthesised via the reaction of TiCl(4) with AsPh(3) (1 : 1 and 1 : 2 equivalents), or one equivalent of Ph(2)AsCH(2)AsPh(2), (t)BuAsH(2) and As(NMe(2))(3). In general, 1 : 1 and 1 : 2 adducts of the type [TiCl(4)(L)(n)] (n = 1, L = AsPh(3), Ph(2)AsCH(2)AsPh(2), and (t)BuAsH(2); n = 2, L = AsPh(3)), were isolated and characterised. However, the reaction of TiCl(4) with As(NMe(2))(3) resulted in a novel exchange between a Cl and an NMe(2) group, yielding the product [TiCl(3)(NMe(2))(mu-NMe(2))(2)AsCl]. The crystal structure of [TiCl(3)(NMe(2))(mu-NMe(2))(2)AsCl] has been determined and showed that the titanium and arsenic atoms are linked via two bridging NMe(2) groups. Additionally, crystal structures for the 1 : 1 and 1 : 2 adducts, [TiCl(4)(AsPh(3))] and [TiCl(4)(AsPh(3))(2)] have been obtained, with Ti-As bond lengths of 2.7465(13) and 2.7238(7) A observed respectively. The decomposition of the compounds has been investigated using thermogravimetric analysis, aerosol-assisted and low pressure chemical vapour deposition.

Preparation of SrTiO3 nanomaterial by a sol–gel-hydrothermal method

A new synthetic route to obtain high-purity strontium titanate, SrTiO3, using the sol–gel-hydrothermal reaction of TiCl4 and a SrCl2 solution in an oxygen atmosphere has been developed. In the synthesized products the SrTiO3 nanoparticles are nearly spherical and decrease in size with the reaction time (48 h) down to a diameter of about 40 nm. The microstructure and composition of the as-synthesized samples were investigated by X-ray diffraction (XRD), high-resolution TEM (HRTEM), Raman spectroscopy, atomic force microscopy (AFM), and energy-dispersive X-ray spectroscopy (EDX). All the samples were identified as cubic perovskite phase.

Ring‐shaped [(TiCl2)(1,3‐P2S8)]2 Molecules Containing Uncommon [P2S8]2– Anions

AbstractIntensely red, moisture‐sensitive crystals of [(TiCl2)(1,3‐P2S8)]2 were obtained by the reaction of TiCl4 and P4S10 at room temperature. The crystal structure determination revealed molecules formally consisting of two units of the anion [1,3‐P2S8]2– connected with two [TiCl2]2+ cations resulting in the ring‐shaped [(TiCl2)(1,3‐P2S8)]2. The thiophosphate [1,3‐P2S8]2– forms a six‐membered ring and has a rather uncommon constitution among the multitude of anionic phosphorus sulfides and selenides.

Syntheses, Structures and Theoretical Investigations of [Li(thf)4]2[Ti2Cu8S4(SPh)10] and [Ti2Ag6S6Cl2(PPhiPr2)6

AbstractThe reaction of CuOAc (OAc = acetate) with TiCl4·2thf and LiSPh in thf leads to the formation of tiny deep‐red crystals of [Li(thf)4]2[Ti2Cu8S4(SPh)10]. The silver/titanium cluster complex [Ti2Ag6S6Cl2(PPhiPr2)6] was synthesized by the reaction of TiCl4·2thf with AgPhCO2 and S(SiMe3)2 in the presence of PPhiPr2. The crystal structures of the compounds were determined by X‐ray analysis of single crystals. Additionally, theoretical investigations were performed to assign the proper chlorine/sulfur atomic positions and to rationalize the bonding situation in 1 and 2. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)

Highly regio- and chemoselective silylation of diethyl α-hydroxyphosphonates, alcohols and phenols in the presence of solid TiCl3(OTf) as a catalyst with hexamethyldisilazane (HMDS) at room temperature in the absence of solvent

Abstract Solid trichlorotitanium(IV) trifluoromethanesulfonate [TiCl3(OTf)] is an easily prepared compound from the reaction of TiCl4 with trifluoromethanesulfonic acid. This solid Ti(IV) based compound is used as a catalyst for highly efficient silylation of diethyl α-hydroxyphosphonates, alcohols and phenols with hexamethyldisilazane (HMDS) at room temperature under solvent-free conditions. Chemo- and regioselectivity for masking different hydroxyl functional groups were observed in the presence of this catalyst.

In situ polymerization of polyethylene/clay nanocomposites using a novel clay‐supported Ziegler‐Natta catalyst

AbstractPolyethylene/clay nanocomposites (PECNC) were synthesized via in situ Ziegler‐Natta catalyst polymerization. Activated catalyst for polymerization of ethylene monomer has been prepared at first by supporting of the cocatalyst on the montmorillonite (MMT) smectite type clay and then active complex for polymerization formed by reaction of TiCl4 and aluminum oxide compound on the clay. Acid wash treatment has been used for increasing hydroxyl group and porosity of the clay and subsequently activity of the catalyst. The nanostructure of composites was investigated by X‐ray diffraction (XRD) and transmission electron microscopy (TEM). Obtained results show that silica layers of the mineral clay in these polyethylene/nanocomposites were exfoliated, intercalated, and uniformly dispersed in the polyethylene matrix even at very high concentration of the clay. Thermogravimetric analysis (TGA) shows good thermal stability of the PECNCs. Differential scanning calorimeter (DSC) results reveal considerable decrease in the crystalline phase of the PECNC samples. Results of permeability analysis show an increase in barrier properties of PECNC films. POLYM. COMPOS., 2009. © 2009 Society of Plastics Engineers

Syntheses, characterization, and ethylene polymerization of titanium and zirconium complexes with [N, O] ligands

Bidentate monoanionic ligands 2-(benzo[d]thiazol-2-yl) phenol (La), 2-(benzo[d]thiazol-2-yl)-6-methylphenol (Lb), 2-(benzo[d]thiazol-2-yl)-6-tert-butyl-4-methylphenol (Lc), 2-(benzo[d]thiazol-2-yl)-6-chlorophenol (Ld), and 2-(benzo[d]thiazol-2-yl)-4-chlorophenol (Le) have been synthesized. Reactions of TiCl4(THF)2 or ZrCl4 with La-Le afford the corresponding titanium complexes Ti[ON]2(R)Cl2 [R = 6-Me (2b); R = 4-Me-6-Bu(t) (2c)], and zirconium complexes Zr[ON]2(R)Cl2 [R = H (3a); R = 6-Me (3b); R = 4-Me-6-Bu(t) (3c); R = 6-Cl (3d); R = 4-Cl (3e)], and Zr[ON(R)]HCl4 x THF [R = 6-Me (4b)], respectively. Complexes 2a-4b were characterized by IR, 1H NMR spectra and elemental analysis. The molecular structures of La, 2b, 2c, 3b, 3c and 4b have been characterized by single-crystal X-ray diffraction analyses. The effect of steric hindrance and the coordination metal on the structure of the products has been investigated. When activated by excess methylaluminoxane (MAO), 2b and 2c, 3a-3e and 4b can be used as catalysts for ethylene polymerization and exhibit moderate to good activities.

Synthesis, Structures and Reactivity of Group 4 Hydrazido Complexes Supported by Calix[4]arene Ligands

Reaction of TiCl(2)(Me(2)Calix) with 2 equiv of LiNHNRR' afforded the corresponding terminal hydrazido(2-) complexes Ti(NNRR')(Me(2)Calix) (R = Ph, R' = Ph (1) or Me; R = R' = Me (3)) which were all structurally characterized. The X-ray structure of Ph(2)NNH(2) is reported for comparison. Compound 1 was also prepared from Na(2)[Me(2)Calix] and Ti(NNPh(2))Cl(2)(py)(3). Reaction of ZrCl(2)(Me(2)Calix) with 2 equiv of LiNHNR(2) afforded only the bis(hydrazido(1-)) complexes Zr(NHNR(2))(2)(Me(2)Calix) (R = Ph or Me). Treatment of Ti(NNMe(2))(Me(2)Calix) (3) with MeI gave the zwitterionic hydrazidium species Ti(NNMe(3))(MeCalix) (6) via a net isomerization reaction which was found to be catalytic in MeI. The corresponding reaction of 3 with CD(3)I gave Ti(NNMe(2)CD(3))(MeCalix) (6-d(3)) with concomitant elimination of MeI. Reaction of 3 with 1 equiv of MeOTf gave [Ti(NNMe(3))(Me(2)Calix)][OTf] (7-OTf) which in turn reacted with (n)Bu(4)NI to form 6 and MeI. Addition of PhCHO to 3 gave the mu-oxo dimer [Ti(mu-O)(Me(2)Calix)](2) and benzaldehyde-dimethylhydrazone. Reaction of either 3 or 6 with (t)BuNCO gave the zwitterionic species Ti{(t)BuNC(NNMe(3))O}(MeCalix) (10) which has been crystallographically characterized. Compound 10 is the formal product of insertion of an isocyanate into the Ti=N(alpha) bond of a titanium hydrazide or hydrazidium species (Me(2)Calix or MeCalix = dianion or trianion of the di- or monomethyl ether of p-tert-butyl calix[4]arene, respectively).

Copolymerization of ethylene with cycloolefins by titanium complexes containing tridentate [o−NSR] ligands

AbstractA family of titanium complexes of the general formula [N‐(3,5‐di‐tert‐butylsalicylidene)‐2‐alkylsulfanylanilinato]Ti(IV)Cl3 5a–f was prepared from the reaction of TiCl4 with the potassium salts of the corresponding ligands. These complexes were fully characterized by various spectroscopic techniques and elemental analyses. The molecular structures of 5b and 5e were further confirmed by single‐crystal X‐ray analyses. Complexes 5a–f (except for 5c) exhibited good to high catalytic activities in ethylene copolymerization with cycloolefins such as norbornene, cyclopentene, dicyclopentadiene in the presence of modified methylaluminoxane. The reaction conditions and the steric hindrance of the alkyl substituents on sulfur atom in the precatalysts influenced strongly the copolymerization behaviors and the structures of the resultant copolymers. Complex 5c with bulky tert‐butylthio sidearm showed both low catalytic activity and comonomer incorporation ratio. The n‐alkylthio complexes 5a, 5d–f all exhibited good ethylene copolymerization capabilities with cycloolefins, which is superior to the corresponding phenylthio complex 5g. © 2008 Wiley Periodicals, Inc. JPolym Sci Part A: Polym Chem 46: 2807–2819, 2008

Reactions of chlorotitanium tri-iso-propoxide with methanol and tributylamine

Reactions of TiCl(OiPr)3 with methanol or tributylamine in heptane resulted in the formation of crystalline Ti4Cl2(μ3-OMe)2(μ2-OMe)4(OiPr)8 and [Bu3NH][Ti2Cl3(OiPr)6], respectively. The solid state structures of both compounds are described.