Inorganic Chemistry
Article
̈
(12) Williams, E. F.; Murray, M. C.; Baird, M. C. Oxidation State(s)
of the Active Titanium Species during Polymerization of Styrene to
Syndiotactic Polystyrene Catalyzed by Cp*TiMe3/B(C6F5)3, Cp*-
TiMe3/[Ph3C][B(C6F5)4], and Cp*TiCl2,3/MAO. Macromolecules
2000, 33, 261−268.
(13) Saito, T.; Nishiyama, H.; Tanahashi, H.; Kawakita, K.; Tsurugi,
H.; Mashima, K. 1,4-Bis(trimethylsilyl)-1,4-diaza-2,5-cyclohexadienes
as Strong Salt-Free Reductants for Generating Low-Valent Early
Transition Metals with Electron-Donating Ligands. J. Am. Chem. Soc.
2014, 136, 5161−5170.
(14) Oswald, T.; Schmidtmann, M.; Beckhaus, R. Crystal Structure
of (η5-pentamethylcyclopentadienyl)titanium(III)dichloride (THF),
C14H23Cl2OTi. Z. Kristallogr. NCS 2016, 231, 637−639.
(27) Schafer, S.; Bauer, H.; Becker, J.; Sun, Y.; Sitzmann, H.
Cyclononatetraenyl-Indenyl Transformations and a Zirconium(III)
Trimer from Bulky Alkylcyclopentadienylzirconium Chlorides. Eur. J.
Inorg. Chem. 2013, 2013, 5694−5700.
(28) (a) Ting, C.; Hammer, M. S.; Baenziger, N. C.; Messerle, L.;
Deak, J.; Li, S.; McElfresh, M. Dimeric and Cyclotrimeric Piano-Stool
Vanadium(III) Dihalides with Unusual Differences in V−V Distance
and Magnetochemistry. Syntheses, Structures, and Reactivities of (η-
C5Me4R)2V2(μ-Br)4 and the Trivanadium Cluster (η-C5Me4R)3V3(μ-
Cl)6, New Mid-Valent Organovanadium Synthons. Organometallics
1997, 16, 1816−1818. (b) Abernethy, C. D.; Bottomley, F.; Decken,
A.; Thompson, R. C. Organometallic Halides: Preparation and
Physical and Chemical Properties of Tris[(η-pentamethylcyclopenta-
dienyl)dichlorovanadium], [(η-C5Me5)V(μ-Cl)2]3. Organometallics
1997, 16, 1865−1869.
́
́
́
(15) Andres, R.; Gomez-Sal, P.; de Jesus, E.; Martín, A.; Mena, M.;
5
́
Yelamos, C. Thermal Decomposition of [(η -C5Me5)TiMe3]: Syn-
thesis and Structure of the Methylidyne Cubane [{(η5-C5Me5)-
Ti}4(μ3-CH)4]. Angew. Chem., Int. Ed. Engl. 1997, 36, 115−117.
(16) Martín, A.; Mena, M.; Pellinghelli, M. A.; Royo, P.; Serrano, R.;
Tiripicchio, A. Some Insertion Reactions into the Ti−Me Bond of
[Ti(η5-C5Me5)MeCl2]; Crystal Structures of [Ti(η5-C5Me5)(η2-
COMe)Cl2] and [{Ti(η5-C5Me5)}2(μ-Cl)2{μ-η4-CH2-(2,6-Me2-
C6H3N)C = C(NC6H3Me2-2,6)CH2}]. J. Chem. Soc., Dalton Trans.
1993, 2117−2122.
(29) (a) Webb, S. P.; Gordon, M. S. Molecular Electronic Structure
and Energetics of the Isomers of Ti2H6. J. Am. Chem. Soc. 1998, 120,
3846−3857. (b) Aikens, C. M.; Gordon, M. S. Electronic Structure
and Magnetic Properties of Y2Ti(μ-X)2TiY2 (X, Y = H, F, Cl, Br)
Isomers. J. Phys. Chem. A 2003, 107, 104−114. (c) Aikens, C. M.;
Gordon, M. S. Influence of Multi-atom Bridging Ligands on the
Electronic Structure and Magnetic Properties of Homodinuclear
Titanium Molecules. J. Phys. Chem. A 2005, 109, 11885−11901.
(30) Roos, B. O.; Taylor, P. R.; Siegbahn, P. E. M. A Complete
Active Space SCF Method (CASSCF) Using a Density Matrix
Formulated Super-CI Approach. Chem. Phys. 1980, 48, 157−173.
(17) Pevec, A. Crystal Structures of (η5-C5Me5)TiCl3 and (η5-
C5Me4H)TiCl3. Acta Chim. Slov. 2003, 50, 199−206.
(18) Blom, R.; Rypdal, K.; Mena, M.; Royo, P.; Serrano, R. The
Molecular Structure of Me3TiCp* in the Gas Phase. J. Organomet.
Chem. 1990, 391, 47−51.
́
(31) Finley, J.; Malmqvist, P. Å.; Roos, B. O.; Serrano-Andres, L.
The Multi-State CASPT2Method. Chem. Phys. Lett. 1998, 288, 299−
306.
́
(19) Palacios, F.; Royo, P.; Serrano, R.; Balcazar, J. L.; Fonseca, I.;
(32) Mendiratta, A.; Cummins, C. C.; Cotton, F. A.; Ibragimov, S.
A.; Murillo, C. A.; Villagran, D. A Diamagnetic Dititanium(III)
Paddlewheel Complex with No Direct Metal−Metal Bond. Inorg.
Chem. 2006, 45, 4328−4330.
Florencio, F. The Hydrolysis of Pentamethylcyclopentadienyltitanium
Trihalides and the Formation of Di-, Tri-, and Tetra-Nuclear μ-Oxo
Complexes. Crystal Structure of [(C5Me5)TiBr(μ-O)]4CHCl3, which
Contains a Ti4O4 Ring. J. Organomet. Chem. 1989, 375, 51−58.
(20) Mahanthappa, M. K.; Cole, A. P.; Waymouth, R. M. Synthesis,
Structure, and Ethylene/α-Olefin Polymerization Behavior of (Cyclo-
pentadienyl)(nitroxide)titanium Complexes. Organometallics 2004,
23, 836−845.
(21) Schmid, G.; Thewalt, U.; Sedmera, P.; Hanus, V.; Mach, K.
Dimeric Structures of Cp′TiCl2 Compounds with Bulky Substituents
at the Cyclopentadienyl Rings. Collect. Czech. Chem. Commun. 1998,
63, 636−645.
(22) Kim, D. Y.; You, Y.; Girolami, G. S. Synthesis and Crystal
Structure of Two (Cyclopentadienyl)titanium(III) Hydroborate
Complexes, [Cp*TiCl(BH4)]2 and Cp2Ti(B3H8). J. Organomet.
Chem. 2008, 693, 981−986.
(23) (a) Martin, R. L.; Winter, G. The Metal-Metal Bond in
Binuclear Di-π-cyclopentadienyltitanium(III) Chloride. J. Chem. Soc.
1965, 0, 4709−4714. (b) Coutts, R. S. P.; Wailes, P. C.; Martin, R. L.
Dimeric Dicyclopentadienyltitanium(III) Halides. J. Organomet.
Chem. 1973, 47, 375−382.
(24) Enders, M.; Fink, J.; Maillant, V.; Pritzkow, H. Synthesis,
Structure, and Reactivity of Metal Complexes with Alkoxysilylmethyl
Ligands. Z. Anorg. Allg. Chem. 2001, 627, 2281−2288.
́
(33) Identical resonance signals have been found in the spectra of
powdered samples of complex 2 prepared by treatment of [Ti(η5-
C5Me5)Cl3] with conventional reducing agents (Li3N, Mg).
(34) (a) Evans, D. F. The Determination of the Paramagnetic
Susceptibility of Substances in Solution by Nuclear Magnetic
Resonance. J. Chem. Soc. 1959, 2003−2005. (b) Sur, S. K.
Measurement of Magnetic Susceptibility and Magnetic Moment of
Paramagnetic Molecules in Solution by High-Field Fourier Transform
NMR Spectroscopy. J. Magn. Reson. 1989, 82, 169−173. (c) Bain, G.
A.; Berry, J. F. Diamagnetic Corrections and Pascal’s Constants. J.
Chem. Educ. 2008, 85, 532−536.
(35) Data reproducibility was checked by susceptibility measure-
ments on three independently synthetized samples of complex 2.
(36) Gambarotta, S.; Floriani, C.; Chiesi-Villa, A.; Guastini, C.
Cyclopentadienyldichlorotitanium(III): A Free-Radical-like Reagent
for Reducing −N=N− Multiple Bonds in Azo and Diazo Compounds.
J. Am. Chem. Soc. 1983, 105, 7295−7301.
(37) A more recent X-ray crystal structure determination of [Ti(η5-
C5H5)Cl2(thf)2] has been reported: Hamilton, E. J. M.; Park, J. S.;
Chen, X.; Liu, S.; Sturgeon, M. R.; Meyers, E. A.; Shore, S. G. β-
Agostic Interactions in 15-Valence-Electron 9-BBN Hydroborate
Half-Sandwich Titanium(III) Complexes. Organometallics 2009, 28,
3973−3980.
(25) (a) Brown, H. C.; Park, W. S.; Cha, J. S.; Cho, B. T.; Brown, C.
A. Addition Compounds of Alkali Metal Hydrides. 28. Preparation of
Potassium Dialkoxymonoalkylborohydrides from Cyclic Boronic
Esters. A New Class of Reducing Agents. J. Org. Chem. 1986, 51,
(38) The [{Ti(η5-C5Me5)(μ-Cl)2}2] complex in the triplet state is
computed to be 1.6 kcal/mol thermodynamically less stable than the
corresponding singlet shown in Scheme 2.
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337−342. (b) Pecharman, A.-F.; Colebatch, A. L.; Hill, M. S.;
McMullin, C. L.; Mahon, M. F.; Weetman, C. Easy Access to
Nucleophilic Boron through Diborane to Magnesium Boryl Meta-
thesis. Nat. Commun. 2017, 8, 15022.
(39) Basta, R.; Harvey, B. G.; Arif, A. M.; Ernst, R. D. Reactions of
SF6 with Organotitanium and Organozirconium Complexes: The
“Inert” SF6 as a Reactive Fluorinating Agent. J. Am. Chem. Soc. 2005,
127, 11924−11925.
(40) Erker, G.; Kru
von α-Titanocenyl-substituierten Dimethylethern: die u
(26) A recent article has demonstrated that the related hydride
chloride [Ti(η5-C5H5)2ClH] species is thermally unstable and
undergoes intermolecular reductive elimination of molecular hydro-
gen to generate [Ti(η5-C5H5)2Cl]; see: Gordon, J.; Hildebrandt, S.;
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ger, C.; Schlund, R. Synthese und Thermolyse
berraschende
̈
Bildung von [(CH3Cp)Ti(OCH3)Cl]4. Z. Naturforsch., B: J. Chem.
̈
Dewese, K. R.; Klare, S.; Gansauer, A.; RajanBabu, T. V.; Nugent, W.
Sci. 1987, 42B, 1009−1016.
(41) The closed-shell singlet excited state is located 41.8 kcal/mol
higher in energy at the optimized structure of the transition state.
A. Demystifying Cp2Ti(H)Cl and Its Enigmatic Role in the Reactions
of Epoxides with Cp2TiCl. Organometallics 2018, 37, 4801−4809.
J
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