Hydrocarbon species µ3-CCH2–, µ3-CCH3 and µ-CHCH3 supported on Ti3O3

Moral, Octavio González‐del; Martı́n, Avelino; Mena, Miguel; Morales-Varela, María del Carmen; Santamarı́a, Cristina

doi:10.1039/b504467g

Cited by 10 publications

(9 citation statements)

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“…[ 10] The crystalline structures of 3, 5 and 11 reveal trinuclear species with an alkylidene group (µ-CHR) bridging two titanium atoms and an alkoxide (OCRЈ) ligand on the third metal center, which is located on the opposite side of the Ti 3 O 3 unit with respect to the alkylidene ligand in a similar way to the situation found in 10 and other trinuclear titanium oxo derivatives. [10,11] The methyl group of the bridging ethylidene in 11 is oriented towards the less crowded region between the three pentamethylcyclopentadienyl rings.…”

Section: Resultsmentioning

confidence: 90%

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Hydron‐Transfer Processes Involving an Organotitanium Oxide and Alcohols

et al. 2009

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Thermal treatment of the μ3‐alkylidyne complexes [{Ti(η5‐C5Me5)(μ‐O)}3(μ3‐CR)] [R = H (1), Me (2)] with alcohols (Ph3COH, Ph2CHOH, PhCH2OH, Ph2CMeOH, tBuOH,Me2CHOH and MeCH2OH) leads to partial hydronation of the alkylidyne moiety supported on the organometallic oxide [Ti3(η5‐C5Me5)3O3] and formation of the new oxo derivatives [{Ti(η5‐C5Me5)(μ‐O)}3(μ‐CHR)(OR′)] [R = H, R′ = Ph3C (3), Ph2CH (4), Ph2CMe (5), tBu (6); R = Me, R′ = Ph3C (7), Ph2CH (8), Ph2CMe (9), tBu (10), Me2CH (11), MeCH2 (12)]. The μ‐CHR group in these species lies above the Ti3O3 ring while the alkoxide ligand is located below it. To gain insight into the mechanism of these reactions, density functional calculations have been performed on the incorporation of alcohols into the model complexes [{Ti(η5‐C5H5)(μ‐O)}3(μ3‐CR)] [R = H (1H), Me (2H)]. Irradiation of solutions containing 1 and the alcohols leads to the compounds [{Ti(η5‐C5Me5)(μ‐O)}3(μ‐CH2)(OR′)] [R′ = Ph3C (13), Ph2CH (14), Ph2CMe (15), tBu (16)] where the methylene (μ‐CH2) and OR′ ligands are located cis with respect to the Ti3O3 unit. Finally, irradiation of solutions of 1 or 2 and Ph3COH in a 1:2 ratio gives the compounds [{Ti(μ3‐O)}3(η5‐C5Me5)2(μ‐CHR)(OCPh3)2] [R = H (19), Me (20)]. The molecular structures of 3, 5, 10, 11, 15 and 20 have been established by single‐crystal X‐ray analysis.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)

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Section: Resultsmentioning

confidence: 90%

“…[10,11] The methyl group of the bridging ethylidene in 11 is oriented towards the less crowded region between the three pentamethylcyclopentadienyl rings.…”

Section: Resultsmentioning

confidence: 99%

Hydron‐Transfer Processes Involving an Organotitanium Oxide and Alcohols

et al. 2009

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“…[10] All the TiÀO bond lengths are in the normal range (1.854(6) ). [6] The bridging ethylidene group shows the C1 atom in a tetrahedral environment and almost equidistant with the two titanium centers (average 2.128(1) ).…”

Section: Resultsmentioning

confidence: 99%

Construction of Titanasiloxanes by Incorporation of Silanols to the Metal Oxide Model [{Ti(η⁵‐C₅Me₅)(μ‐O)}₃(μ₃‐CR)]: DFT Elucidation of the Reaction Mechanism

Carbó

Moral

Martı́n

et al. 2008

Chemistry A European J

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A family of novel titanasiloxanes containing the structural unit ([Ti(eta 5-C5Me5)O]3) were synthesized by hydron-transfer processes involving reactions with equimolecular amounts of mu3-alkylidyne derivatives [(Ti(eta 5-C5Me5)(mu-O))(3)(mu3-CR)] (R=H (1), Me (2)) and monosilanols, R3'Si(OH), silanediols, R2'Si(OH)2, and the silanetriol tBuSi(OH)3. Treatment of 1 and 2 with triorganosilanols (R'=Ph, iPr) in hexane affords the new metallasiloxane derivatives [(Ti(eta 5-C5Me5)(mu-O))(3)(mu-CHR)(OSiR3')] (R=H, R'=Ph (3), iPr (4); R=Me, R'=Ph (5), iPr (6)). Analogous reactions with silanediols, (R'=Ph, iPr), give the cyclic titanasiloxanes [(Ti(eta 5-C5Me5)(mu-O))(3)(mu-O2SiR'2)(R)] (R=Me, R'=Ph (7), iPr (8); R=Et, R'=Ph (9), iPr (10)). Utilization of tBuSi(OH)3 with 1 or 2 at room temperature produces the intermediate complexes [(Ti(eta 5-C5Me5) (mu-O))(3)(mu-O2Si(OH)tBu)(R)] (R=Me (11), Et(12)). Further heating of solutions of 11 or 12 affords the same compound with an adamantanoid structure, [(Ti(eta 5-C5Me5)(mu-O))3(mu-O3SitBu)] (13) and methane or ethane elimination, respectively. The X-ray crystal structures of 3, 4, 6, 8, 10, 12, and 13 have been determined. To gain an insight into the mechanism of these reactions, DFT calculations have been performed on the incorporation of monosilanols to the model complex [(Ti(eta 5-C5H5)(mu-O))3(mu3-CMe)] (2 H). The proposed mechanism consists of three steps: 1) hydron transfer from the silanol to one of the oxygen atoms of the Ti3O3 ring, forming a titanasiloxane; 2) intramolecular hydron migration to the alkylidyne moiety; and 3) a mu-alkylidene ligand rotation to give the final product.

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“…[6] Herein we discuss the evolution of the ethylidyne fragment when the molecular model [{TiCp*(µ-O)} 3 (µ 3 -CMe)] (1) tries to incorporate alkaline-earth derivatives. Scheme 1.…”

Section: Introductionmentioning

confidence: 99%

“…[4] However, at present, detailed studies concerning the titanium surface reactivity are scarce and evidence for the formation of ethylidyne has only recently appeared during the decomposition of ethylene on carbon-modified (6); R = Ph 3 CO, M = Mg (7a,b), Ca (8), Sr (9)]. This substitution can also be performed on 3 and 4 by treatment with the starting complex 1, which gives the corner-shared double cubanes [M{(µ 3 -O) 3 (Ti 3 Cp* 3 )(µ 3 -CCH 2 titanium surfaces.…”

Section: Introductionmentioning

confidence: 99%

Titanium–Alkaline Earth Molecular Oxides as Supports for Carbanions Derived from μ₃‐Ethylidyne Groups

et al. 2006

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Treatment of the μ3‐ethylidyne complex [{TiCp*(μ‐O)}3(μ3‐CMe)] (1) (Cp* = η5‐C5Me5) with the alkaline earth amides [M{N(SiMe3)2}2(thf)2] (M = Mg, Ca, Sr) promotes the deprotonation of the alkylidyne moiety μ3‐CMe and leads to the oxoheterometallocubane derivatives [{(thf)x(Me3Si)2NM}(μ3‐O)3{Ti3Cp*3(μ3‐CCH2)}] [M = Mg, x = 0 (2a); Ca, x = 1 (3); Sr, x = 1 (4)]. In the case of the magnesium amide, complex 2a is obtained together with the isomer [{(Me3Si)2NMg}(μ3‐O)3{Ti3Cp*3(μ3‐η2‐CHCH)}] (2b). The addition of pentamethylcyclopentadiene (C5Me5H) or triphenylmethanol (Ph3COH) to these compounds causes the displacement of the amide fragment to give the heterometallocubanes [RM(μ3‐O)3{Ti3Cp*3(μ3‐C2H2)}] [R = C5Me5, M = Ca (5), Sr (6); R = Ph3CO, M = Mg (7a,b), Ca (8), Sr (9)]. This substitution can also be performed on 3 and 4 by treatment with the starting complex 1, which gives the corner‐shared doublecubanes [M{(μ3‐O)3(Ti3Cp*3)(μ3‐CCH2)}2] [M = Ca (11), Sr (12)]. Complexes 2a,b do not react with 1, and heating of this mixture affords the edge‐linked double cubane [Mg(μ4‐O)(μ3‐O)2{Ti3Cp*3(μ3‐CCH)}]2 (10). The combination of the barium reagents [Ba(CH2Ph)2] or [Ba{N(SiMe3)2}2] with 1 leads to the corner‐shared double cubane [Ba{(μ3‐O)3(Ti3Cp*3)(μ3CCH2)}2] (13). The molecular structures of 3 and 10 have been established by single‐crystal X‐ray analysis. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)

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Hydrocarbon species µ3-CCH2–, µ3-CCH3 and µ-CHCH3 supported on Ti3O3

Cited by 10 publications

References 10 publications

Hydron‐Transfer Processes Involving an Organotitanium Oxide and Alcohols

Hydron‐Transfer Processes Involving an Organotitanium Oxide and Alcohols

Construction of Titanasiloxanes by Incorporation of Silanols to the Metal Oxide Model [{Ti(η⁵‐C₅Me₅)(μ‐O)}₃(μ₃‐CR)]: DFT Elucidation of the Reaction Mechanism

Titanium–Alkaline Earth Molecular Oxides as Supports for Carbanions Derived from μ₃‐Ethylidyne Groups

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Hydrocarbon species µ3-CCH2–, µ3-CCH3 and µ-CHCH3 supported on Ti3O3

Cited by 10 publications

References 10 publications

Hydron‐Transfer Processes Involving an Organotitanium Oxide and Alcohols

Hydron‐Transfer Processes Involving an Organotitanium Oxide and Alcohols

Construction of Titanasiloxanes by Incorporation of Silanols to the Metal Oxide Model [{Ti(η5‐C5Me5)(μ‐O)}3(μ3‐CR)]: DFT Elucidation of the Reaction Mechanism

Titanium–Alkaline Earth Molecular Oxides as Supports for Carbanions Derived from μ3‐Ethylidyne Groups

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About

Construction of Titanasiloxanes by Incorporation of Silanols to the Metal Oxide Model [{Ti(η⁵‐C₅Me₅)(μ‐O)}₃(μ₃‐CR)]: DFT Elucidation of the Reaction Mechanism

Titanium–Alkaline Earth Molecular Oxides as Supports for Carbanions Derived from μ₃‐Ethylidyne Groups