Hydrocarbon Soluble Alkali-Metal-Aluminium Hydride Surrog[ATES]

A series of group 1 hydrocarbon-soluble donor free aluminates [AM((BuDHP)-Bu-t)(TMP)Al(Bu-i)(2)] (AM=Li, Na, K, Rb) have been synthesised by combining an alkali metal dihydropyridyl unit [(2-(BuC5H5N)-Bu-t)AM)] containing a surrogate hydride (sp(3) C-H) with [(Bu-i)(2)Al(TMP)]. These aluminates have been characterised by X-ray crystallography and NMR spectroscopy. While the lithium aluminate forms a monomer, the heavier alkali metal aluminates exist as polymeric chains propagated by non-covalent interactions between the alkali metal cations and the alkyldihydropyridyl units. Solvates [(THF)Li-((BuDHP)-Bu-t)(TMP)Al(Bu-i)(2)] and [(TMEDA)Na((BuDHP)-Bu-t)(TMP)Al(Bu-i)(2)] have also been crystallographically characterised. Theoretical calculations show how the dispersion forces tend to increase on moving from Li to Rb, as opposed to the electrostatic forces of stabilization, which are orders of magnitude more significant. Having unique structural features, these bimetallic compounds can be considered as starting points for exploring unique reactivity trends as alkali-metal-aluminium hydride surrog[ATES].

Automated summary

A series of unique aluminates have been synthesized, and it was found that the alkali metal has a significant influence on their properties. Theoretical calculations showed that dispersion forces have a greater impact on stability than electrostatic forces.