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).
Original language | English |
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Pages (from-to) | 1370-1375 |
Number of pages | 6 |
Journal | Inorganica Chimica Acta |
Volume | 360 |
Issue number | 4 |
DOIs | |
Publication status | Published - 1 Mar 2007 |
Keywords
- alkali metal
- magnesium
- amide
- agostic
- x-ray crystallography
- heterobimetallic