Titanium(III) chloride in methanol with small amounts of water

Goldberg, Ira B.; Goeppinger, W. F.

doi:10.1021/ic50118a058

Cited by 8 publications

(7 citation statements)

References 2 publications

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“…If we assume that the two types of protons have a similar relaxation behaviour, this ratio suggests a total of five oxygen ligands from methyl groups, four in the equatorial plane and one along g^. This is in agreement with other ESR studies of Ti 3 + that suggest ligation of five methanol molecules to Ti 3 + at low cation concentrations, when the ratio of solvent molecules to cations is very high [27], The site has a tetragonally distorted octahedral symmetry.…”

Section: V3 Local Environment Of Ti 3 + In Methanol and In Swollen Nsupporting

confidence: 89%

Solvation Structure of the Ti(III) Ion in Methanol Solutions and in Perfluorinated Ionomers Swollen by Water and Methanol. A Study by ESR and ENDOR

Schlick

Myers

Sjöqvist

et al. 1992

Zeitschrift Für Naturforschung A

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The local environment of Ti 3+ cations in methanol solutions and in Nafion perfluorinated ionomers swollen by water and methanol has been studied by electron spin resonance (ESR) and by *H and 2 H electron nuclear double resonance (ENDOR) spectroscopies. The two major sites reflecting the ligation of the cations as a function of solvent structure and cation concentration have been analyzed, using whenever possible the method of orientation selection for the ENDOR transitions. The distance R N of the protons from the central cation, and the angle 0 N between the symmetry axis of Ti 3+ and the Ti 3 + -proton vector have been deduced by evaluating the dipolar interaction tensor and by simulating the orientation dependence of the ENDOR signal. For site 1 of Ti 3+ in methanol {g n = 1.986 and g L = 1.894) no orientation selection was possible, and R N values in the range 4.1 to 4.6 Ä are suggested from the ENDOR splittings. For site 2 of Ti 3+ in methanol (011 = 1.943 and g L = 1.960) equatorial and axial methyl protons have been detected; the R N values deduced from the simulations are 3.95 and 4.35 Ä, respectively. For Ti 3+ in Nafion swollen by water (g || = 1.997 and g L = 1.907), equatorial and axial protons from OH groups have been detected, and the ENDOR spectra were simulated with R N values of 2.60 and 3.10 A respectively for these protons.

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Section: V3 Local Environment Of Ti 3 + In Methanol and In Swollen Nsupporting

confidence: 89%

Solvation Structure of the Ti(III) Ion in Methanol Solutions and in Perfluorinated Ionomers Swollen by Water and Methanol. A Study by ESR and ENDOR

Schlick

Myers

Sjöqvist

et al. 1992

Zeitschrift Für Naturforschung A

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“…The HYSCORE spectrum with predominant contributions of species 2 thus indicates that the solvation sphere of the Ti(III) ions is composed of directly coordinated methanol or methoxy groups and possibly H 2 O or OH À groups and excludes the presence of directly coordinated Cl À ions. A sharp EPR absorption was detected by Goldberg 29 and by Waters and Maki 10 for TiCl 3 in methanol solutions which contained methoxy ions. Moreover, spectra of frozen solutions characterized by an asymmetric signal consisting of two lines with experimental values of g > = 1.960 and g J = 1.944 were tentatively assigned to a [Ti(OCH 3 )(CH 3 OH)] 2+ species.…”

Section: The Epr Spectrum Of Ticl 3 Dissolved In Anhydrous and Hydrat...mentioning

confidence: 98%

“…The second species (species 2) is characterized by a small g anisotropy and was clearly demonstrated to have no directly coordinated Cl À ions. Different authors 6,9,10,29 suggested that the low anisotropic spectrum is characterized by the presence of directly coordinated hydroxy or methoxy groups. To verify these hypotheses we computed the EPR properties of different Ti(III) complexes characterized by different symmetries with OH À or CH 3 O À as directly coordinated ions.…”

Section: Computational Modelingmentioning

confidence: 99%

EPR investigation of TiCl₃dissolved in polar solvents – implications for the understanding of active Ti(iii) species in heterogeneous Ziegler–Natta catalysts

Maurelli

Morra

Doorslaer

et al. 2014

Phys. Chem. Chem. Phys.

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5Multi-frequency continuous-wave and pulsed EPR techniques are employed to investigate Ti(III)-chloro complexes obtained by dissolving TiCl 3 in anhydrous and hydrated methanol. Two distinctly different species, characterized by different g matrices are observed in the two cases. Hyperfine sublevel correlation (HYSCORE) spectroscopy is found to be a powerful method to identify the type of nuclei surrounding the Ti 3+ ion. For the first time, the hyperfine and nuclear quadrupole data of Ti(III)-bound 10 35/37 Cl nuclei are reported together with 1 H and 13 C hyperfine data of the coordinated methanol molecules.DFT modelling allows interpreting the measured spin Hamiltonian parameters in terms of microscopic models of the solvated species. The theoretical observable properties (g matrix, 35/37 Cl, 1 H and 13 C hyperfine tensors) are in quantitative agreement with the experiments for two families of complexes: [TiCl n (CH 3 OH) 6-n )] (3-n)+ (with n ranging from 0 to 2) and [Ti(CH 3 OH) 5 (OH)] 2+ or 15 [Ti(CH 3 OH) 5 (OCH 3 )] 2+ . The first complex is observed in anhydrous methanol, while the second type of complexes is observed when water is added to the solution; the presence of OH -and/or CH 3 O -species being promoted by water hydrolysis. The results obtained for the frozen solutions are critically compared to EPR spectra recorded for a MgCl 2 -supported Ti-based Ziegler-Natta model catalyst.

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“…It has been pointed out that the upper limit of stability of the esr signal of stable radicals is about 20-30 sec,6 because removal of the anion radical by convection is likely to begin about this time. This may be the reason that the calculated points fall slightly below the experimental curve at times between 15 and 20 sec. The agreement between the calculated and experimental signal time behavior is very good.…”

Section: Resultsmentioning

confidence: 85%

“…T(sec) Figure 1. Esr signal time dependence for 7.5 nW diethylfumarate at fp = 15 sec, / = 0.21 mA. Points show calculated valves for ki1 determined at S(2fp).…”

Section: Methodsmentioning

confidence: 99%

Simultaneous electrochemical-electron spin resonance measurements. III. Determination of rate constants for second-order radical anion dimerization

Goldberg¹,

Boyd²,

Hirasawa³

et al. 1974

J. Phys. Chem.

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Publication costs assisted by Rockwell InternationalIn-situ electron spin resonance-electrochemical measurements have been used to measure the rate constants for the dimerization of diethylfumarate, dimethylfumarate, cinnamonitrile, and fumaronitrile radical anions in dimethylformamide solution. The mechanism was found to be second order in radical anion with rate constants for these reactions at 23°of 33, 160, 2100, and >10® M-1 sec-1, respectively. Both the mechanism and the rate constants agree with values from electrochemical studies. The applicability of controlled current pulse with simultaneous esr detection for elucidation of reaction mechanism is demonstrated.

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Titanium(III) chloride in methanol with small amounts of water

Cited by 8 publications

References 2 publications

Solvation Structure of the Ti(III) Ion in Methanol Solutions and in Perfluorinated Ionomers Swollen by Water and Methanol. A Study by ESR and ENDOR

Solvation Structure of the Ti(III) Ion in Methanol Solutions and in Perfluorinated Ionomers Swollen by Water and Methanol. A Study by ESR and ENDOR

EPR investigation of TiCl₃dissolved in polar solvents – implications for the understanding of active Ti(iii) species in heterogeneous Ziegler–Natta catalysts

Simultaneous electrochemical-electron spin resonance measurements. III. Determination of rate constants for second-order radical anion dimerization

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Titanium(III) chloride in methanol with small amounts of water

Cited by 8 publications

References 2 publications

Solvation Structure of the Ti(III) Ion in Methanol Solutions and in Perfluorinated Ionomers Swollen by Water and Methanol. A Study by ESR and ENDOR

Solvation Structure of the Ti(III) Ion in Methanol Solutions and in Perfluorinated Ionomers Swollen by Water and Methanol. A Study by ESR and ENDOR

EPR investigation of TiCl3dissolved in polar solvents – implications for the understanding of active Ti(iii) species in heterogeneous Ziegler–Natta catalysts

Simultaneous electrochemical-electron spin resonance measurements. III. Determination of rate constants for second-order radical anion dimerization

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EPR investigation of TiCl₃dissolved in polar solvents – implications for the understanding of active Ti(iii) species in heterogeneous Ziegler–Natta catalysts