Arene Complexes of the Group 4 Metals

Fortier, Skye; Gómez‐Torres, Alejandra; Saucedo, Carlos

doi:10.1016/b978-0-12-820206-7.00012-3

Cited by 5 publications

(8 citation statements)

References 138 publications

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“…The reactivity of 2 and 3 with alkynes was explored, as cyclotrimerization by low-valent titanium has been extensively documented. − Treating solutions of either 2 or 3 with excess PhCCPh or Me 3 SiCCSiMe 3 at variable temperatures resulted in no evident reactivity, while treatment with MeCCMe promotes rapid consumption of the starting materials as reflected by a significant change in coloration from dark brown to dark red. Attempts to characterize the composition of the product were unfruitful with no evidence for the formation of hexamethylbenzene.…”

Section: Results and Discussionmentioning

confidence: 99%

“…Discrete Ti(I) compounds are exceedingly rare and limited to the arene sandwich complexes [(η 6 -1,3,5- i Pr 3 C 6 H 3 ) 2 Ti][BAr 4 ] (BAr 4 = C 6 H 5 , p -C 6 H 4 F, 3,5-C 6 H 3 (CF 3 ) 2 ). , Therefore, our system offers a novel entry point for examining the reactivity of monovalent titanium. On the other hand, Ti(0) complexes, stabilized by π-acceptors such as CO or arenes, are well established though relatively few in number, , paling in comparison to the known chemistry of Ti(II), Ti(III), and Ti(IV) compounds.…”

Section: Results and Discussionmentioning

confidence: 99%

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Molecular Capacitors: Accessible 6- and 8-Electron Redox Chemistry from Dimeric “Ti(I)” and “Ti(0)” Synthons Supported by Imidazolin-2-Iminato Ligands

et al. 2022

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Reduction of the diamagnetic Ti(III)/Ti(III) dimer [Cl 2 Ti(μ-NIm Dipp )] 2 (1) (NIm Dipp = [1,3-bis(Dipp)imidazolin-2-iminato] − , Dipp = C 6 H 3 -2,6-i Pr 2 ) with 4 and 6 equiv of KC 8 generates the intramolecularly arene-masked, dinuclear titanium compounds [(μ-Nη 6 -Im Dipp )Ti] 2 (2) and {[(Et 2 O) 2 K](μ-N-μ-η 6 :η 6 -Im Dipp )Ti} 2 (3), respectively, in modest yields. The compounds have been structurally characterized by X-ray crystallographic analysis, and inspection of the bond metrics within the η 6 -coordinated aryl substituent of the bridging imidazolin-2-iminato ligand shows perturbation of the aromatic system most consistent with two-electron reduction of the ring. As such, 2 and 3 can be assigned respectively as possessing metal centers in formal Ti(III)/Ti(III) and Ti(II)/Ti(II) oxidation states. Exploration of their redox chemistry reveal the ability to reduce several substrate equivalents. For instance, treatment of 2 with excess C 8 H 8 (COT) forms the novel COTbridged complex [(Im Dipp N)(η 8 -COT)Ti](μ-η 2 :η 3 -COT)[Ti(η 4 -COT)(NIm Dipp )] (4) that dissociates in THF solutions to give mononuclear (Im Dipp N)Ti(η 8 -COT)(THF) (5). Addition of COT to 3 yields heterometallic [(Im Dipp N)(η 4 -COT)Ti(μ-η 4 :η 5 -COT)K(THF)-(μ-η 6 :η 4 -COT)Ti(NIm Dipp )(μ-η 4 :η 4 -COT)K(THF) 2 ] n (6). Compounds 4 and 5 are the products of the 4-electron oxidation of 2, while 6 stands as the 8-electron oxidation product of 3. Reduction of organozides was also explored. Low temperature reaction of 2 with 4 equiv of AdN 3 gives the terminal and bridged imido complex [(Im Dipp N)Ti(�NAd)](μ-NAd) 2 [Ti(NIm Dipp )(N 3 Ad)] (7) that undergoes intermolecular C−H activation of toluene at room temperature to afford the amido compound [(Im Dipp N)Ti-(NHAd)](μ-NAd) 2 [Ti(C 6 H 4 Me)(NIm Dipp )] (8-tol). These complexes are the 6-electron oxidation products of the reaction of 2 with AdN 3 . Furthermore, treatment of 3 with 4 equiv of AdN 3 produces the thermally stable Ti(III)/Ti(III) terminal and bridged imido [K(18-crown-6)(THF) 2 ]{[(Im Dipp N)Ti(NAd)](μ-NAd) 2 K[Ti(NIm Dipp )]} (10). Altogether, these reactions firmly establish 2 and 3 as unprecedented Ti(I)/Ti(I) and Ti(0)/Ti(0) synthons with the clear capacity to effect multielectron reductions ranging from 4 to 8 electrons.

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Section: Results and Discussionmentioning

confidence: 99%

Section: Results and Discussionmentioning

confidence: 99%

Molecular Capacitors: Accessible 6- and 8-Electron Redox Chemistry from Dimeric “Ti(I)” and “Ti(0)” Synthons Supported by Imidazolin-2-Iminato Ligands

et al. 2022

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“…1A ). 19 For example, Arnold reported a coordinated Ti–toluene complex 1 supported by a N , N ′-bis(trimethylsilyl)benzamidinate ligand 20 while Ozerov reported a Ti-arene complex 2 supported by a p-tert -butyl calix[4]arene ligand. 21 Inverse-sandwich Ti complexes with bridging arenes have also been characterized, as demonstrated by a Cp*Ti adduct 3 reported by Mach 22 and a tripyrrole Ti adduct 4 reported by Gambarotta and Budzelaar.…”

Section: Introductionmentioning

confidence: 99%

Reassessment of N₂ activation by low-valent Ti-amide complexes: a remarkable side-on bridged bis-N₂ adduct is actually an arene adduct

et al. 2022

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“…Reactivity of 2 and 3 with alkynes was explored as cyclotrimerization by low-valent titanium has been extensively documented. [36][37][38][39][40][41][42] Treating solutions of either 2 or 3 with excess PhCCPh or Me3SiCCSiMe3 at variable temperatures resulted in no evident reactivity, while treatment with MeCCMe promotes rapid consumption of the starting materials as reflected by a significant change in coloration from dark brown to dark red. Attempts to characterize the composition of the product were unfruitful with no evidence for the formation of hexamethylbenzene.…”

Section: Resultsmentioning

confidence: 99%

“…Discrete Ti(I) compounds are exceedingly rare and limited to the arene sandwich complexes [(η 6 -1,3,5-i Pr3C6H3)2Ti][BAr] (BAr = C6H5, p-C6H4F, 3,5-C6H3(CF3)2). 42,57 Therefore, our system offers a novel entry point for examining the reactivity of monovalent titanium. On the other hand, Ti(0) complexes, stabilized by πacceptors such as CO or arenes, are well established though relatively few in number, [58][59] paling in comparison to the known chemistry of Ti(II), Ti(III), and Ti(IV) compounds.…”

Section: Resultsmentioning

confidence: 99%

Molecular Capacitors: Accessible 6- and 8-electron Redox Chemistry from Dimeric “Ti(I)” and “Ti(0)” Synthons Support-ed by Imidazolin-2-Iminato Ligands.

Gómez‐Torres

Mavragani

Metta‐Magaña

et al. 2022

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Reduction of the diamagnetic Ti(III)/Ti(III) dimer [Cl2Ti(μ-NImDipp)]2 (1) (NImDipp = [1,3-bis(Dipp)imidazolin-2-iminato]-, Dipp = NC6H3-2,6-Pri2) with 4 and 6 equiv of KC8 generates the intramolecularly arene-masked, dinuclear titanium com-pounds [(μ-N-μ-η6-ImDipp)Ti]2 (2) and {[(Et2O)2K](μ-N-μ-η6:η6-ImDipp)Ti}2 (3), respectively, in modest yields. The compounds have been structurally characterized by X-ray crystallographic analysis and inspection of the bond metrics within the η6-coordinated aryl substituent of the bridging imidazolin-2-iminato ligand show perturbation of the aromatic system most consistent with two-electron reduction of the ring. As such, 2 and 3 can be assigned respectively as possessing metal centers in formal Ti(III)/Ti(III) and Ti(II)/Ti(II) oxidation states. Exploration of their redox chemistry reveal the ability to reduce several substrate equivalents. For instance, treatment of 2 with excess C8H8 (COT) forms the novel COT-bridged complex [(ImDippN)(η8-COT)Ti](μ-η2:η3-COT)[Ti(η4-COT)(NImDipp)] (4) that dissociates in THF solutions to give mononuclear (ImDippN)Ti(η8-COT)(THF) (5). Addition of COT to 3 yields heterometallic [(ImDippN)(η4-COT)Ti(μ-η4:η5-COT)K(THF)(μ-η6:η4-COT)Ti(NImDipp)(μ-η4:η4-COT)K(THF)2]n (6). Compounds 2 and 5 are the products of the 4-electron oxidation of 2, while 6 stands as the 8-electron oxidation product of 3. Reduction of organozides was also explored. Low temperature reaction of 2 with 4 equiv of AdN3 gives the terminal and bridged imido complex [(ImDippN)Ti(=NAd)](μ-NAd)2[Ti(NImDipp)(N3Ad)] (7) that undergoes intermolecular C-H activation of toluene at room temperature to afford the amido compound [(ImDippN)Ti(NHAd)](μ-NAd)2[Ti(C6H4Me)(NImDipp)] (8-tol). These complexes are the 6-electron oxidation products of the reaction of 2 with AdN3. Furthermore, treatment of 3 with 4 equiv of AdN3 produces the thermally sta-ble Ti(III)/Ti(III) terminal and bridged imido [K(18-crown-6)(THF)2]{[(ImDippN)Ti(NAd)](μ-NAd)2K[Ti(NImDipp)]} (10). Alto-gether, these reactions firmly establish 2 and 3 as unprecedented Ti(I)/Ti(I) and Ti(0)/Ti(0) synthons with the clear ca-pacity to effect multi-electron reductions ranging from 4 – 8 electrons.

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Arene Complexes of the Group 4 Metals

Cited by 5 publications

References 138 publications

Molecular Capacitors: Accessible 6- and 8-Electron Redox Chemistry from Dimeric “Ti(I)” and “Ti(0)” Synthons Supported by Imidazolin-2-Iminato Ligands

Molecular Capacitors: Accessible 6- and 8-Electron Redox Chemistry from Dimeric “Ti(I)” and “Ti(0)” Synthons Supported by Imidazolin-2-Iminato Ligands

Reassessment of N₂ activation by low-valent Ti-amide complexes: a remarkable side-on bridged bis-N₂ adduct is actually an arene adduct

Molecular Capacitors: Accessible 6- and 8-electron Redox Chemistry from Dimeric “Ti(I)” and “Ti(0)” Synthons Support-ed by Imidazolin-2-Iminato Ligands.

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Arene Complexes of the Group 4 Metals

Cited by 5 publications

References 138 publications

Molecular Capacitors: Accessible 6- and 8-Electron Redox Chemistry from Dimeric “Ti(I)” and “Ti(0)” Synthons Supported by Imidazolin-2-Iminato Ligands

Molecular Capacitors: Accessible 6- and 8-Electron Redox Chemistry from Dimeric “Ti(I)” and “Ti(0)” Synthons Supported by Imidazolin-2-Iminato Ligands

Reassessment of N2 activation by low-valent Ti-amide complexes: a remarkable side-on bridged bis-N2 adduct is actually an arene adduct

Molecular Capacitors: Accessible 6- and 8-electron Redox Chemistry from Dimeric “Ti(I)” and “Ti(0)” Synthons Support-ed by Imidazolin-2-Iminato Ligands.

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Reassessment of N₂ activation by low-valent Ti-amide complexes: a remarkable side-on bridged bis-N₂ adduct is actually an arene adduct