Synthesis and structural characterisation of mixed alkalimetal-magnesium mixed ligand alkyl-amido ate complexes

Prokopis C. Andrikopoulos, D.R. Armstrong, A.R. Kennedy, R.E. Mulvey, C.T. O'Hara, Rene Rowlings, Susan Weatherstone

Research output: Contribution to journalArticle

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Abstract

Using two different reaction methodologies, two alkali metal–magnesium alkyl bis(amide) complexes were synthesised. First the lithium magnesiate LiMg{μ-N(SiMe3)2}2(tBu) (1) was prepared by combining equimolar quantities of tBuLi and Mg{N(SiMe3)2}2 in hydrocarbon solvent. An X-ray crystallographic study revealed that the asymmetric unit of 1 has a dinuclear arrangement, based on a planar Li–N–Mg–N four-membered ring. As a result of the presence of intermolecular agostic interactions between the Li centre of one asymmetric unit and a methyl group which is resident on the terminal tert-butyl group of another, 1 is polymeric in the solid-state. Second the sodium magnesiate NaMg{μ-N(SiMe3)2}2(tBu) · (OEt2) (2) was prepared by reacting two molar equivalents of Na{N(SiMe3)2} with one molar equivalent of tBuMgCl in hydrocarbon/diethyl ether solution. X-ray crystallographic analysis revealed that the asymmetric unit of 2 consisted of a dinuclear molecular arrangement. As expected it is not polymeric due to the coordination of the Lewis basic ether. Stabilizing intramolecular agostic NaC bonds are observed (where C is a methyl group resident on a Si atom).
LanguageEnglish
Pages1370-1375
Number of pages6
JournalInorganica Chimica Acta
Volume360
Issue number4
DOIs
Publication statusPublished - 1 Mar 2007

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Hydrocarbons
Ether
Magnesium
magnesium
Ethers
Ligands
Alkali Metals
X rays
ligands
Alkali metals
synthesis
hydrocarbons
Lithium
Amides
diethyl ether
Sodium
Atoms
alkali metals
amides
ethers

Keywords

  • alkali metal
  • magnesium
  • amide
  • agostic
  • x-ray crystallography
  • heterobimetallic

Cite this

Andrikopoulos, Prokopis C. ; Armstrong, D.R. ; Kennedy, A.R. ; Mulvey, R.E. ; O'Hara, C.T. ; Rowlings, Rene ; Weatherstone, Susan. / Synthesis and structural characterisation of mixed alkalimetal-magnesium mixed ligand alkyl-amido ate complexes. In: Inorganica Chimica Acta. 2007 ; Vol. 360, No. 4. pp. 1370-1375.
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Synthesis and structural characterisation of mixed alkalimetal-magnesium mixed ligand alkyl-amido ate complexes. / Andrikopoulos, Prokopis C.; Armstrong, D.R.; Kennedy, A.R.; Mulvey, R.E.; O'Hara, C.T.; Rowlings, Rene; Weatherstone, Susan.

In: Inorganica Chimica Acta, Vol. 360, No. 4, 01.03.2007, p. 1370-1375.

Research output: Contribution to journalArticle

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T1 - Synthesis and structural characterisation of mixed alkalimetal-magnesium mixed ligand alkyl-amido ate complexes

AU - Andrikopoulos, Prokopis C.

AU - Armstrong, D.R.

AU - Kennedy, A.R.

AU - Mulvey, R.E.

AU - O'Hara, C.T.

AU - Rowlings, Rene

AU - Weatherstone, Susan

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N2 - Using two different reaction methodologies, two alkali metal–magnesium alkyl bis(amide) complexes were synthesised. First the lithium magnesiate LiMg{μ-N(SiMe3)2}2(tBu) (1) was prepared by combining equimolar quantities of tBuLi and Mg{N(SiMe3)2}2 in hydrocarbon solvent. An X-ray crystallographic study revealed that the asymmetric unit of 1 has a dinuclear arrangement, based on a planar Li–N–Mg–N four-membered ring. As a result of the presence of intermolecular agostic interactions between the Li centre of one asymmetric unit and a methyl group which is resident on the terminal tert-butyl group of another, 1 is polymeric in the solid-state. Second the sodium magnesiate NaMg{μ-N(SiMe3)2}2(tBu) · (OEt2) (2) was prepared by reacting two molar equivalents of Na{N(SiMe3)2} with one molar equivalent of tBuMgCl in hydrocarbon/diethyl ether solution. X-ray crystallographic analysis revealed that the asymmetric unit of 2 consisted of a dinuclear molecular arrangement. As expected it is not polymeric due to the coordination of the Lewis basic ether. Stabilizing intramolecular agostic NaC bonds are observed (where C is a methyl group resident on a Si atom).

AB - Using two different reaction methodologies, two alkali metal–magnesium alkyl bis(amide) complexes were synthesised. First the lithium magnesiate LiMg{μ-N(SiMe3)2}2(tBu) (1) was prepared by combining equimolar quantities of tBuLi and Mg{N(SiMe3)2}2 in hydrocarbon solvent. An X-ray crystallographic study revealed that the asymmetric unit of 1 has a dinuclear arrangement, based on a planar Li–N–Mg–N four-membered ring. As a result of the presence of intermolecular agostic interactions between the Li centre of one asymmetric unit and a methyl group which is resident on the terminal tert-butyl group of another, 1 is polymeric in the solid-state. Second the sodium magnesiate NaMg{μ-N(SiMe3)2}2(tBu) · (OEt2) (2) was prepared by reacting two molar equivalents of Na{N(SiMe3)2} with one molar equivalent of tBuMgCl in hydrocarbon/diethyl ether solution. X-ray crystallographic analysis revealed that the asymmetric unit of 2 consisted of a dinuclear molecular arrangement. As expected it is not polymeric due to the coordination of the Lewis basic ether. Stabilizing intramolecular agostic NaC bonds are observed (where C is a methyl group resident on a Si atom).

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KW - magnesium

KW - amide

KW - agostic

KW - x-ray crystallography

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