Complexes of Titanium in Oxidation State iv

Cuenca, Tomás

doi:10.1016/b0-08-045047-4/00061-3

Cited by 9 publications

(2 citation statements)

References 1,876 publications

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“…The ring bonding distances are displayed in Figure . Similar behavior in coordinated aryl rings has been observed by Hagadorn and Arnold in (L Me )Ti(η 6 -PhCH 3 ) (L Me = C 6 H 4 -1,2(NC( p -tolyl)NPh) 2 ) − and Stephan and co-workers in compounds [Cp 2 Ti(NP t Bu 2 (2-C 6 H 4 Ph))] . We assume that cyclization occurs in 2 and the other species because of the very low (two) metal electron count and the increased availability of either d or s valence orbitals to participate in a further reaction.…”

Section: Resultssupporting

confidence: 62%

“…The Ti–C bond distances to the carbons of the interacting aryl ring are in the range of ca. 2.49–2.69 Å and are longer than those observed in titanocene or for other titanium aryl interactions which range from 2.2 to 2.4 Å. , The shortest Ti–C distance to the flanking aryl ring (Ti–C(8)= 2.4854(16) Å) is considerably longer than about 2.11 Å that would be expected for a Ti(III)–C single bond . There is a considerable difference (ca.…”

Section: Resultsmentioning

confidence: 80%

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Synthesis and Characterization of the Titanium Bisamide Ti{N(H)Ar^iPr₆}₂(Ar^iPr₆= C₆H₃-2,6-(C₆H₂-2,4,6-ⁱPr₃)₂and Its TiCl{N(H)Ar^iPr₆}₂Precursor: Ti(II) → Ti(IV) Cyclization

et al. 2013

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The titanium bisamido complex Ti{N(H)Ar(iPr6)}2 (Ar(iPr6) = C6H3-2,6-(C6H2-2,4,6-(i)Pr3)2 (2), along with its three-coordinate titanium(III) precursor, TiCl{N(H)Ar(iPr6)}2 (1), have been synthesized and characterized. Compound 1 was obtained via the stoichiometric reaction of LiN(H)Ar(iPr6) with the Ti(III) complex TiCl3·2NMe3 in trimethylamine. Reduction of 1 with 1 equiv of KC8 afforded Ti{N(H)Ar(iPr6)}2 (2) in moderate yield. Both 1 and 2 were characterized by X-ray crystallography, NMR, and IR spectroscopy, magnetic studies, and by density functional theory (DFT) computations. The precursor 1 has quasi-four-coordinate coordination at the titanium atom, with bonding to two amido nitrogens and a chlorine as well as a secondary interaction to a flanking aryl ring of a terphenyl substituent. Compound 2 displays a very distorted four-coordinate metal environment in which the titanium atom is bound to two amido nitrogens and to two carbons from a terphenyl aryl ring. This structure is in sharp contrast to the expected two-coordinate linear structure that was observed in its first row metal (V-Ni) analogues. Magnetic studies confirm a d(1) electron configuration for 1 but indicate that Ti{N(H)Ar(iPr6)}2 (2) is diamagnetic at ambient temperature consistent with the oxidation of titanium to Ti(IV). The different structure of 2 is attributed to the high reducing tendency of the Ti(II) in comparison to the other metals.

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Section: Resultssupporting

confidence: 62%

Section: Resultsmentioning

confidence: 80%

Synthesis and Characterization of the Titanium Bisamide Ti{N(H)Ar^iPr₆}₂(Ar^iPr₆= C₆H₃-2,6-(C₆H₂-2,4,6-ⁱPr₃)₂and Its TiCl{N(H)Ar^iPr₆}₂Precursor: Ti(II) → Ti(IV) Cyclization

et al. 2013

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Mechanistic Studies on Programmed C―O/C―H Activation with Valence‐Adjusted Ti‐Complexes

et al. 2023

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Comprehensive SummaryTwo‐electron reduction of [N2NBn]TiIVCl2 (3) gave a highly reactive [N2N]TiII species, which underwent C—O bond activation of THF (tetrahydrofuran) to generate [N2NBn]TiIV[O(CH2)4] (4) through oxidative addition. The resulted TiIV–Csp3 bond in oxametallacyclohexane was tantamount to the elaborately‐designed Ti‐alkyl complexes, competent to activate intramolecular Csp2–H bond, forming ortho‐cyclometalated complex [N2NCH2C6H4]TiIV(OnBu) (5). Key intermediates were isolated and fully characterized by X‐ray crystallography. Mechanistic studies revealed that the oxidative addition of C—O bond took place at TiII‐center via a radical intermediate, while a Csp2–H bond activation proceeded by σ‐bond metathesis with a kitelike four‐centered TiIV‐transition state.

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Neutral Dimethylzirconocene Complexes as Initiators for the Ring‐Opening Polymerization of ϵ‐Caprolactone

et al. 2012

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The synthesis, structures, and ring‐opening polymerization (ROP) activity of new dimethyl‐ansa‐ and ‐non‐ansa‐zirconocene complexes are reported. The substituted indene precursors 1‐C9H7R [R = CH3 (1), CH2Ph (2) and C2H4(C4H7O2) (3)] were synthesised by treating RBr [R = CH2Ph and C2H4(C4H7O2)] or MeI with indenyllithium. Likewise, bridged indenyl/cyclopentadiene compounds [Me2Si(3‐C9H6R)(C5Me4H)] [R = H (4), CH3 (5), CH2Ph (6) and C2H4(C4H7O2) (7)] were obtained by treating the lithium salt of the appropriately substituted indene with ClSiMe2(C5Me4H). ansa‐Indenyl–cyclopentadienylmetallocenes [Zr{Me2Si(3‐η5‐C9H5R)(η5‐C5Me4)}Cl2] [R = H (8), CH3 (9), CH2Ph (10), C2H4(C4H7O2) (11)] were subsequently obtained by treating the dilithium salts of the corresponding ligands with ZrCl4 in toluene. The dimethyl derivatives [Zr{Me2Si(3‐η5‐C9H5R)(η5‐C5Me4)}Me2] [R = H (12), CH3 (13), CH2Ph (14), C2H4(C4H7O2) (15)] were prepared by treating the corresponding ansa‐zirconocene dichloride complex with MgMeBr. Dialkyl derivative [Zr{Me2Si{3‐η5‐C9H5(CH2Ph)}(η5‐C5Me4)}(CH2SiMe3)2] (16) was prepared by adding 2 equiv. of LiCH2SiMe3 to complex 10. Mixed indenyl/cyclopentadienylzirconocene complexes [Zr(η5‐C9H6R)(η5‐C5H5)Cl2] [R = H (17), C2H4(C4H7O2) (18)] were prepared by treating the lithium salt of the appropriately substituted indene with [Zr(η5‐C5H5)Cl3]. Likewise, dimethyl derivatives [Zr(η5‐C9H6R)(η5‐C5H5)Me2] [R = H (19), C2H4(C4H7O2) (20)] were prepared by treating the corresponding mixed indenyl/cyclopentadienyl dichloride complex with 2 equiv. of MgMeBr. The X‐ray crystal structures of 7, 12, and 13 were also established. Finally, comparative catalytic studies of zirconium complexes 12–16, 19 and 20 in ROP reactions of ϵ‐caprolactone are described.

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Complexes of Titanium in Oxidation State iv

Cited by 9 publications

References 1,876 publications

Synthesis and Characterization of the Titanium Bisamide Ti{N(H)Ar^iPr₆}₂(Ar^iPr₆= C₆H₃-2,6-(C₆H₂-2,4,6-ⁱPr₃)₂and Its TiCl{N(H)Ar^iPr₆}₂Precursor: Ti(II) → Ti(IV) Cyclization

Synthesis and Characterization of the Titanium Bisamide Ti{N(H)Ar^iPr₆}₂(Ar^iPr₆= C₆H₃-2,6-(C₆H₂-2,4,6-ⁱPr₃)₂and Its TiCl{N(H)Ar^iPr₆}₂Precursor: Ti(II) → Ti(IV) Cyclization

Mechanistic Studies on Programmed C―O/C―H Activation with Valence‐Adjusted Ti‐Complexes

Neutral Dimethylzirconocene Complexes as Initiators for the Ring‐Opening Polymerization of ϵ‐Caprolactone

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Complexes of Titanium in Oxidation State iv

Cited by 9 publications

References 1,876 publications

Synthesis and Characterization of the Titanium Bisamide Ti{N(H)AriPr6}2(AriPr6= C6H3-2,6-(C6H2-2,4,6-iPr3)2and Its TiCl{N(H)AriPr6}2Precursor: Ti(II) → Ti(IV) Cyclization

Synthesis and Characterization of the Titanium Bisamide Ti{N(H)AriPr6}2(AriPr6= C6H3-2,6-(C6H2-2,4,6-iPr3)2and Its TiCl{N(H)AriPr6}2Precursor: Ti(II) → Ti(IV) Cyclization

Mechanistic Studies on Programmed C―O/C―H Activation with Valence‐Adjusted Ti‐Complexes

Neutral Dimethylzirconocene Complexes as Initiators for the Ring‐Opening Polymerization of ϵ‐Caprolactone

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Synthesis and Characterization of the Titanium Bisamide Ti{N(H)Ar^iPr₆}₂(Ar^iPr₆= C₆H₃-2,6-(C₆H₂-2,4,6-ⁱPr₃)₂and Its TiCl{N(H)Ar^iPr₆}₂Precursor: Ti(II) → Ti(IV) Cyclization

Synthesis and Characterization of the Titanium Bisamide Ti{N(H)Ar^iPr₆}₂(Ar^iPr₆= C₆H₃-2,6-(C₆H₂-2,4,6-ⁱPr₃)₂and Its TiCl{N(H)Ar^iPr₆}₂Precursor: Ti(II) → Ti(IV) Cyclization