Monocyclopentadienyltitanium(III) Complexes with Hydridoborato Ligands

Calvo-Molina, Adrián; Horno, Estefanía del; Pérez‐Redondo, Adrián; Yélamos, Carlos; Zapata, Rosa Guillermina Dolorier

doi:10.1021/acs.organomet.2c00580

Cited by 4 publications

(3 citation statements)

References 95 publications

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“…Nonetheless for reasons of simplification, the monomer is used in the following schemes. This structural motif is typical for unsaturated metal triflato complexes and can be found in several works. ,− The slightly asymmetrical Ti–O bonds (2.1528(19) Å and 2.180(2) Å) are best described as elongated single bonds according to the covalent radii (Σr cov (Ti–O) = 1.99 Å) and are similar to other triflato bridged titanium complexes ([Cp*Ti(BH 4 )(μ-O 2 SOCF 3 ) 2 ]: 2.123(3) Å, [Cp*TiCp*(CF 3 SO 3 )(μ-O 2 SOCF 3 ) 2 )X] 2 : 2.164(3) Å, 2.142(4) Å) . The Ti–O bonds are much longer than those of the monomeric complexes Ti1a , Ti3a , and Cp 2 Ti(OTf) 2 .…”

Section: Resultssupporting

confidence: 62%

From Coordination to Noncoordination: Syntheses and Substitution Lability Studies of Titanium Triflato Complexes

Schwitalla,

Yusufzadeh,

Schmidtmann

et al. 2024

Inorg. Chem.

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A new concept for obtaining cationic complexes with triflate counteranions from coordinating triflato ligands was developed. Various routes are leading to titanium(IV) and titanium(III) triflato complexes efficiently. The reactions of pentafulvene titanium complexes with either triflic acid or silver triflate give the corresponding titanium(IV) triflato complexes in excellent yields. Hydrolysis of the titanium(IV) bistriflato complexes leads to cationic aqua complexes via displacement of the triflato ligand, which consequently acts as a noncoordinating anion. A functionalized titanium(IV) monotriflato complex was synthesized by insertion of a nitrile into the Ti−C bond and the triflato ligand was displaced by an NHC. While the titanium(IV) complexes are mostly inert toward substrates, the donor-free titanium(III) triflato complex is a strong Lewis acid and forms various adducts with monodentate Lewis bases. The titanium(III) complex was oxidized by reaction with TEMPO, resulting in a diamagnetic titanium(IV) complex. The reaction with bidentate ligands results in cationic titanium(III) complexes due to displacement of the triflato ligand by the bidentate ligands. Treatment with acetone leads to an aldol reaction of two acetone molecules and the formation of a cationic diacetone alcohol complex.

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Section: Resultssupporting

confidence: 62%

From Coordination to Noncoordination: Syntheses and Substitution Lability Studies of Titanium Triflato Complexes

Schwitalla,

Yusufzadeh,

Schmidtmann

et al. 2024

Inorg. Chem.

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“…As part of a research program devoted to the development of half-sandwich group 4 hydride complexes, we have been interested in exploring the reactivity of amine–borane adducts with derivatives [M(η 5 -C 5 Me 5 )X 3 ]. In particular, our group has reported the isolation of titanium(III) hydride or amidoborane complexes in the reactions of trialkyl derivatives [Ti(η 5 -C 5 Me 5 )R 3 ] (R = CH 2 SiMe 3 , Me) with NHR 2 BH 3 (R 2 = Me 2 , H 2 , H t Bu). , The reaction of the zirconium and hafnium analogues [M(η 5 -C 5 Me 5 )(CH 2 SiMe 3 ) 3 ] with NHMe 2 BH 3 gave thermally unstable dialkyl(dimethylamidoborane) compounds [M(η 5 -C 5 Me 5 )(CH 2 SiMe 3 ) 2 (NMe 2 BH 3 )] without change in the oxidation state of the metal centers .…”

Section: Introductionmentioning

confidence: 99%

“…As part of a research program devoted to the development of half-sandwich group 4 hydride complexes, 30 we have been interested in exploring the reactivity of amine–borane adducts with derivatives [M(η 5 -C 5 Me 5 )X 3 ]. In particular, our group has reported the isolation of titanium(III) hydride or amidoborane complexes in the reactions of trialkyl derivatives [Ti(η 5 -C 5 Me 5 )R 3 ] (R = CH 2 SiMe 3 , Me) with NHR 2 BH 3 (R 2 = Me 2 , H 2 , H t Bu).…”

Section: Introductionmentioning

confidence: 99%

Half-Sandwich Zirconium and Hafnium Amidoborane Complexes: Precursors of Hydride Derivatives

Greño,

Pérez-Redondo,

Torrijos

et al. 2024

Inorg. Chem.

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Half-sandwich zirconium(IV) and hafnium(IV) complexes with amidoborane and hydride ligands have been isolated in the stoichiometric reactions of mono-(pentamethylcyclopentadienyl)metal alkyl and amido derivatives with the amine−boranes NHR 2 BH 3 (R 2 = H 2 , Me 2 , HtBu). Treatment of the tris(trimethylsilylmethyl) complexes [M(η 5 -C 5 Me 5 )(CH 2 SiMe 3 ) 3 ] with NH 3 BH 3 (3 equiv) gives the sevencoordinate species [M(η 5 -C 5 Me 5 )(NH 2 BH 3 ) 3 ] (M = Zr (1), Hf (2)) with three κ 2 N,H-NH 2 BH 3 ligands. The tris(neophyl) [M(η 5 -C 5 Me 5 )(CH 2 CMe 2 Ph) 3 ] or tris(dimethylamido) [M(η 5 -C 5 Me 5 )-(NMe 2 ) 3 ] derivatives react with NHMe 2 BH 3 (≥3 equiv) to afford bis(dimethylamidoborane) hydride complexes [M(η 5 -C 5 Me 5 )H(NMe 2 BH 3 ) 2 ] (M = Zr (3), Hf (4)) via thermally unstable [M(η 5 -C 5 Me 5 )(NMe 2 BH 3 ) 3 ] species. The reaction of [M(η 5 -C 5 Me 5 )(NMe 2 ) 3 ] and NH 2 tBuBH 3 (≥4 equiv) affords analogous mixed amidoborane hydride derivatives [M(η 5 -C 5 Me 5 )H-(NHtBuBH 3 )(NMe 2 BH 3 )] (M = Zr (5), Hf (6)) with κ 2 N,H-NHtBuBH 3 and κ 3 N,H,H-NMe 2 BH 3 ligands. The addition of NHR 2 BH 3 (≥1 equiv) on the mono(dimethylamido) complexes [M(η 5 -C 5 Me 5 )Cl 2 (NMe 2 )] in hexane leads to the precipitation of the ionic compounds [(NHR 2 ) 2 BH 2 ][{M(η 5 -C 5 Me 5 )Cl 2 } 2 (μ-H) 3 ] (R 2 = Me 2 , M = Zr (7), Hf (8); R 2 = HtBu, M = Zr (9), Hf (10)). Molecular hydride species [Cl 2 (η 5 -C 5 Me 5 )M(μ-Cl)(μ-H) 2 M(η 5 -C 5 Me 5 )Cl(NH 2 tBu)] (M = Zr (11), Hf (12)) could be isolated from mixtures of complexes [M(η 5 -C 5 Me 5 )Cl 2 (NMe 2 )] and lower ratios of NH 2 tBuBH 3 . The zirconium complex 11 decomposes in solution to give the mononuclear tert-butylamido derivative [Zr(η 5 -C 5 Me 5 )Cl 2 (NHtBu)] (13) along with other byproducts.

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Stabilization of Ethane‐Like Dianionic Diborane(6) in Monometallic Titanium Complexes and its Subsequent B(sp³)−B(sp³) Bond Cleavage

Bairagi,

Giri,

Joshi

et al. 2024

Angewandte Chemie

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Treatment of [Cp*TiCl3] with [LiBH4∙THF] followed by thermolysis with [Ph2E2] (E = S or Se) resulted in the formation of classical diborane(6) complexes, [(Cp*Ti)(η4‐B2H4LL')] (L = C6H4E; L' = C6H5E; 1a: E = S, 1b: E = Se), stabilized at titanium template. To the best of our knowledge, they are the first examples of mono‐metallic classical diborane(6) complexes. The bonding analysis and theoretical studies suggest that the stabilization of these diborane(6) species is due to the presence of four bridging ligands in ĸ4‐fashion, where two of them are phenyl thiolates/selenolates that provide more electrons to the electron‐deficient titanium center. Reactions of these diborane(6) species with [M(CO)5∙THF] (M = Mo, W) led to the cleavage of electron‐precise B(sp3)‐B(sp3) bond that yielded ĸ3‐hydridoborato complexes [(Cp*Ti)(ĸ3‐BH3R)(μ‐EPh)2{M(CO)4}] (2a‐c: R = H, 3a‐c: R = Ph). In an attempt to isolate the Te‐analogue of 1a‐b, a similar reaction was performed; however, the complex was too unstable to be isolated. Interestingly, the treatment of this unstable intermediate with [W(CO)5∙THF] yielded [(Cp*Ti)(ĸ3‐BH3R)(μ‐TePh)2{W(CO)4}] (2d: R = H, 3d: R = Ph) that are analogues of 2a‐c and 3a‐c, respectively. Formation of these species provide indirect evidence for existence of unstable [(Cp*Ti)(η4‐B2H4LL')] (L = C6H4Te; L' = C6H5Te; 1c).

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Monocyclopentadienyltitanium(III) Complexes with Hydridoborato Ligands

Cited by 4 publications

References 95 publications

From Coordination to Noncoordination: Syntheses and Substitution Lability Studies of Titanium Triflato Complexes

From Coordination to Noncoordination: Syntheses and Substitution Lability Studies of Titanium Triflato Complexes

Half-Sandwich Zirconium and Hafnium Amidoborane Complexes: Precursors of Hydride Derivatives

Stabilization of Ethane‐Like Dianionic Diborane(6) in Monometallic Titanium Complexes and its Subsequent B(sp³)−B(sp³) Bond Cleavage

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Monocyclopentadienyltitanium(III) Complexes with Hydridoborato Ligands

Cited by 4 publications

References 95 publications

From Coordination to Noncoordination: Syntheses and Substitution Lability Studies of Titanium Triflato Complexes

From Coordination to Noncoordination: Syntheses and Substitution Lability Studies of Titanium Triflato Complexes

Half-Sandwich Zirconium and Hafnium Amidoborane Complexes: Precursors of Hydride Derivatives

Stabilization of Ethane‐Like Dianionic Diborane(6) in Monometallic Titanium Complexes and its Subsequent B(sp3)−B(sp3) Bond Cleavage

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Product

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Stabilization of Ethane‐Like Dianionic Diborane(6) in Monometallic Titanium Complexes and its Subsequent B(sp³)−B(sp³) Bond Cleavage