Amidobis(pentamethylcyclopentadienyl)titanium(III)

Brady, Edward L.; Telford, Jason R.; Mitchell, G. H.; Lukens, Wayne W.

doi:10.1107/s0108270194005792

“…3 The nitrogen atoms of the NH 2 groups have almost planar environments (the sum of the surrounding angles 356°—N(3) and 357°—N(4)), which indicates a lowering of the inversion barrier at the nitrogen center due to the electropositive aluminum atom 13. A similar phenomenon was observed for [Cp${{\ast \hfill \atop 2\hfill}}$ TiNH 2 ] and [{[DippN(SiMe 3 )]Ge(NH 2 )NH} 3 ] (Cp*=C 5 Me 5 , Dipp=diisopropylphenyl) 14. 15…”

Section: Methodssupporting

confidence: 71%

Preparation of Monomeric [LAl(NH₂)₂]—A Main‐Group Metal Diamide Containing Two Terminal NH₂ Groups

Jancik

¹

,

Pineda

²

,

Pinkas

³

et al. 2004

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Dedicated to Professor Dietmar Seyferth on the occasion of his 75th birthdayAluminum amides supported by organic ligands are important molecular precursors for the preparation of aluminum nitrides, such as Al À N based semiconductors and Al À N ceramics.[1] Amides with the general formula [R 2 Al(NH 2 )], in which R corresponds to an organic substituent, are rare. The presence of a reactive NH 2 group, which can be involved in further substitution reactions, may lead to mixed-metal imides that have the AlÀN(H)ÀM skeleton (M = metal atom). However the known amides show a strong tendency to oligomerize and form unstable trimers [{R 2 Al(m-NH 2 )} 3 ] (R = Me, tBu) [2a,b] or dimers [{R 2 Al(m-NH 2 )} 2 ] (R= Me 3 Si) [2b-d] because of the Lewis acidity of the aluminum center and the presence of the electron lone pair at the nitrogen atom of the NH 2 group. The steric bulk of the substituents is the major factor that determines the degree of association. However, the mechanism of the formation of the product remains unclear. The adducts of composition R 3 Al·NH 3 are thermodynamically unstable and thus decompose at elevated temperatures to the corresponding amides under elimination of alkanes. [2a, 4] So far there are no reports known on the preparation of aluminum amides by treating KNH 2 or NaNH 2

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“…3 The nitrogen atoms of the NH 2 groups have almost planar environments (the sum of the surrounding angles 356°—N(3) and 357°—N(4)), which indicates a lowering of the inversion barrier at the nitrogen center due to the electropositive aluminum atom 13. A similar phenomenon was observed for [Cp${{\ast \hfill \atop 2\hfill}}$ TiNH 2 ] and [{[DippN(SiMe 3 )]Ge(NH 2 )NH} 3 ] (Cp*=C 5 Me 5 , Dipp=diisopropylphenyl) 14. 15…”

Section: Methodssupporting

confidence: 71%

Preparation of Monomeric [LAl(NH₂)₂]—A Main‐Group Metal Diamide Containing Two Terminal NH₂ Groups

Jancik

¹

,

Pineda

²

,

Pinkas

³

et al. 2004

View full text Add to dashboard Cite

Dedicated to Professor Dietmar Seyferth on the occasion of his 75th birthdayAluminum amides supported by organic ligands are important molecular precursors for the preparation of aluminum nitrides, such as Al À N based semiconductors and Al À N ceramics.[1] Amides with the general formula [R 2 Al(NH 2 )], in which R corresponds to an organic substituent, are rare. The presence of a reactive NH 2 group, which can be involved in further substitution reactions, may lead to mixed-metal imides that have the AlÀN(H)ÀM skeleton (M = metal atom). However the known amides show a strong tendency to oligomerize and form unstable trimers [{R 2 Al(m-NH 2 )} 3 ] (R = Me, tBu) [2a,b] or dimers [{R 2 Al(m-NH 2 )} 2 ] (R= Me 3 Si) [2b-d] because of the Lewis acidity of the aluminum center and the presence of the electron lone pair at the nitrogen atom of the NH 2 group. The steric bulk of the substituents is the major factor that determines the degree of association. However, the mechanism of the formation of the product remains unclear. The adducts of composition R 3 Al·NH 3 are thermodynamically unstable and thus decompose at elevated temperatures to the corresponding amides under elimination of alkanes. [2a, 4] So far there are no reports known on the preparation of aluminum amides by treating KNH 2 or NaNH 2

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“…[4] It is therefore unsurprising that the only structurally authenticated examples of Group , prepared by the reaction between the respective methyl complex and ammonia. [5][6][7] Reaction with ammonia is employed to promote the controlled chemical deposition of the technologically important metal nitride materials [TiN] and [Zr 3 N 4 ] from tetrakis(dimethylamido)titanium or -zirconium. The initially formed species is assumed to be [MA C H T U N G T R E N N U N G (NMe 2 ) 3 A C H T U N G T R E N N U N G (NH 2 )] and intermediates involving NH 2 , NH and N ligands have been postulated.…”

Section: Introductionmentioning

confidence: 99%

The Synthesis, Structure and Reactivity of B(C₆F₅)₃‐Stabilised Amide (MNH₂) Complexes of the Group 4 Metals

Mountford

¹

,

Clegg

²

,

Coles

³

et al. 2007

Chemistry A European J

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Treatment of the homoleptic titanium amides [Ti(NR(2))(4)] (R=Me or Et) with the Brønsted acidic reagent H(3)NB(C(6)F(5))(3) results in the elimination of one molecule of amine and the formation of the four-coordinate amidoborate complexes [Ti(NR(2))(3){NH(2)B(C(6)F(5))(3)}], the identity of which was confirmed by X-ray crystallography. The reaction with [Zr(NMe(2))(4)] proceeds similarly but with retention of the amine ligand to give the trigonal-bipyramidal complex [Zr(NMe(2))(3){NH(2)B(C(6)F(5))(3)}(NMe(2)H)]. Cyclopentadienyl (Cp) amidoborate complexes, [MCp(NR(2))(2){NH(2)B(C(6)F(5))(3)}] (M=Ti, R=Me or Et; M=Zr, R=Me) can be prepared from [MCp(NR(2))(3)] and H(3)NB(C(6)F(5))(3), and exhibit greater thermal stability than the cyclopentadienyl-free compounds. H(3)NB(C(6)F(5))(3) reacts with nBuLi or LiN(SiMe(3))(2) to give LiNH(2)B(C(6)F(5))(3), which complexes with strong Lewis acids to form ion pairs that contain weakly coordinating anions. The attempted synthesis of metallocene amidoborate complexes from dialkyl or diamide precursors and H(3)NB(C(6)F(5))(3) was unsuccessful. However, LiNH(2)B(C(6)F(5))(3) does react with the highly electrophilic reagents [MCp(2)Me(mu-Me)B(C(6)F(5))(3)] to give [MCp(2)Me(mu-NH(2))B(C(6)F(5))(3)] (M=Zr or Hf). Comparison of the molecular structures of the Group 4 amidoborate complexes reveals very similar B--N, Ti--N and Zr--N bond lengths, which are consistent with a description of the bonding as a dative interaction between an {M(L)(n)(NH(2))} fragment and the Lewis acid B(C(6)F(5))(3). Each of the structures has an intramolecular hydrogen-bonding arrangement in which one of the nitrogen-bonded hydrogen atoms participates in a bifurcated FHF interaction to ortho-F atoms.

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Amidobis(pentamethylcyclopentadienyl)titanium(III)

Cited by 21 publications

References 1 publication

Preparation of Monomeric [LAl(NH₂)₂]—A Main‐Group Metal Diamide Containing Two Terminal NH₂ Groups

Preparation of Monomeric [LAl(NH₂)₂]—A Main‐Group Metal Diamide Containing Two Terminal NH₂ Groups

Preparation of Monomeric [LAl(NH₂)₂]—A Main‐Group Metal Diamide Containing Two Terminal NH₂ Groups

The Synthesis, Structure and Reactivity of B(C₆F₅)₃‐Stabilised Amide (MNH₂) Complexes of the Group 4 Metals

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Amidobis(pentamethylcyclopentadienyl)titanium(III)

Cited by 21 publications

References 1 publication

Preparation of Monomeric [LAl(NH2)2]—A Main‐Group Metal Diamide Containing Two Terminal NH2 Groups

Preparation of Monomeric [LAl(NH2)2]—A Main‐Group Metal Diamide Containing Two Terminal NH2 Groups

Preparation of Monomeric [LAl(NH2)2]—A Main‐Group Metal Diamide Containing Two Terminal NH2 Groups

The Synthesis, Structure and Reactivity of B(C6F5)3‐Stabilised Amide (MNH2) Complexes of the Group 4 Metals

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Preparation of Monomeric [LAl(NH₂)₂]—A Main‐Group Metal Diamide Containing Two Terminal NH₂ Groups

Preparation of Monomeric [LAl(NH₂)₂]—A Main‐Group Metal Diamide Containing Two Terminal NH₂ Groups

Preparation of Monomeric [LAl(NH₂)₂]—A Main‐Group Metal Diamide Containing Two Terminal NH₂ Groups

The Synthesis, Structure and Reactivity of B(C₆F₅)₃‐Stabilised Amide (MNH₂) Complexes of the Group 4 Metals