Crystal structure of a representative mixed adduct of trimethylaluminium and a lithium amide and a theoretical MO study on model systems

D.R. Armstrong, F.J. Craig, A.R. Kennedy, R.E. Mulvey

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Abstract

Reaction of the simple alane adduct [Me3Al · HN(CH2Ph)2] (2) with the lithium amide [(PhCH2)2NLi] leads to the formation of the mixed adduct [Me3Al · (PhCH2)2NLi · HN(CH2Ph)2] (1). The crystal structures of 1 and 2 are reported. Exhibiting a four-membered, mixed-metal, mixedanion ring-core, the structure of 1 is unusual in containing a monomeric lithium dibenzylamide fragment. Such fragments generally convert to aza-allyl derivatives, so its existence here can be attributed to the stabilising effect of the attached Me3Al ligand. Crystalline 2 adopts the classical, distorted-tetrahedral arrangement of simple monomeric alane adducts. Ab initio MO calculations on model systems show that mixed adduct formation from Me3Al and Me2NLi is exothermic, while further reaction to give Me2AlNMe2 and MeLi (i.e., complete transmetallation) is endothermic.
LanguageEnglish
Pages1293-1300
Number of pages7
JournalChemische berichte
Volume129
DOIs
Publication statusPublished - 1996

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Lithium
Amides
Crystal structure
Metals
Crystalline materials
Ligands
Derivatives

Keywords

  • alane adduct
  • monomeric lithium dibenzylamide fragment
  • aza-allyl derivatives

Cite this

@article{df1a66435b0e4c07bd6ce603ce4af2ef,
title = "Crystal structure of a representative mixed adduct of trimethylaluminium and a lithium amide and a theoretical MO study on model systems",
abstract = "Reaction of the simple alane adduct [Me3Al · HN(CH2Ph)2] (2) with the lithium amide [(PhCH2)2NLi] leads to the formation of the mixed adduct [Me3Al · (PhCH2)2NLi · HN(CH2Ph)2] (1). The crystal structures of 1 and 2 are reported. Exhibiting a four-membered, mixed-metal, mixedanion ring-core, the structure of 1 is unusual in containing a monomeric lithium dibenzylamide fragment. Such fragments generally convert to aza-allyl derivatives, so its existence here can be attributed to the stabilising effect of the attached Me3Al ligand. Crystalline 2 adopts the classical, distorted-tetrahedral arrangement of simple monomeric alane adducts. Ab initio MO calculations on model systems show that mixed adduct formation from Me3Al and Me2NLi is exothermic, while further reaction to give Me2AlNMe2 and MeLi (i.e., complete transmetallation) is endothermic.",
keywords = "alane adduct, monomeric lithium dibenzylamide fragment, aza-allyl derivatives",
author = "D.R. Armstrong and F.J. Craig and A.R. Kennedy and R.E. Mulvey",
year = "1996",
doi = "10.1002/cber.19961291024",
language = "English",
volume = "129",
pages = "1293--1300",
journal = "Chemische berichte",
issn = "0009-2940",
publisher = "John Wiley and Sons Ltd",

}

TY - JOUR

T1 - Crystal structure of a representative mixed adduct of trimethylaluminium and a lithium amide and a theoretical MO study on model systems

AU - Armstrong, D.R.

AU - Craig, F.J.

AU - Kennedy, A.R.

AU - Mulvey, R.E.

PY - 1996

Y1 - 1996

N2 - Reaction of the simple alane adduct [Me3Al · HN(CH2Ph)2] (2) with the lithium amide [(PhCH2)2NLi] leads to the formation of the mixed adduct [Me3Al · (PhCH2)2NLi · HN(CH2Ph)2] (1). The crystal structures of 1 and 2 are reported. Exhibiting a four-membered, mixed-metal, mixedanion ring-core, the structure of 1 is unusual in containing a monomeric lithium dibenzylamide fragment. Such fragments generally convert to aza-allyl derivatives, so its existence here can be attributed to the stabilising effect of the attached Me3Al ligand. Crystalline 2 adopts the classical, distorted-tetrahedral arrangement of simple monomeric alane adducts. Ab initio MO calculations on model systems show that mixed adduct formation from Me3Al and Me2NLi is exothermic, while further reaction to give Me2AlNMe2 and MeLi (i.e., complete transmetallation) is endothermic.

AB - Reaction of the simple alane adduct [Me3Al · HN(CH2Ph)2] (2) with the lithium amide [(PhCH2)2NLi] leads to the formation of the mixed adduct [Me3Al · (PhCH2)2NLi · HN(CH2Ph)2] (1). The crystal structures of 1 and 2 are reported. Exhibiting a four-membered, mixed-metal, mixedanion ring-core, the structure of 1 is unusual in containing a monomeric lithium dibenzylamide fragment. Such fragments generally convert to aza-allyl derivatives, so its existence here can be attributed to the stabilising effect of the attached Me3Al ligand. Crystalline 2 adopts the classical, distorted-tetrahedral arrangement of simple monomeric alane adducts. Ab initio MO calculations on model systems show that mixed adduct formation from Me3Al and Me2NLi is exothermic, while further reaction to give Me2AlNMe2 and MeLi (i.e., complete transmetallation) is endothermic.

KW - alane adduct

KW - monomeric lithium dibenzylamide fragment

KW - aza-allyl derivatives

U2 - 10.1002/cber.19961291024

DO - 10.1002/cber.19961291024

M3 - Article

VL - 129

SP - 1293

EP - 1300

JO - Chemische berichte

T2 - Chemische berichte

JF - Chemische berichte

SN - 0009-2940

ER -