A series of group 1 hydrocarbon-soluble donor free aluminates [AM( t BuDHP)(TMP)Al( i Bu) 2 ] (AM=Li, Na, K, Rb) have been synthesised by combining an alkali metal dihydropyridyl unit [(2-t BuC 5 H 5 N)AM)] containing a surrogate hydride (sp 3 CÀ H) with [( i Bu) 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-( t BuDHP)(TMP)Al( i Bu) 2 ] and [(TMEDA)Na( t BuDHP)(TMP)Al( i Bu) 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].

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The ability of the β-CH functionality in a butylmagnesium cation [Me6TREN-Mg-n-Bu]+ to quantitatively reduce benzophenone has been demonstrated. The hydridic nature of the β-CH functionality is highlighted by its abstraction using B(C6F5)3. β-CH abstraction over alkylation in [Me6TREN-Mg-n-Bu]+ is dependent on the nature of the incoming electrophile and the polarity of the solvent.

We report the synthesis, structure and reactivity of molecular amidomagnesium cations bearing tris{2-(dimethylamino)-ethyl}amine (Me6TREN).

The sterically hindered monomeric alkoxomagnesium compound [(Me 6 TREN)MgOCHPh 2 ][B(C 6 F 5 ) 4 ] (1) has been used to explore the role of magnesium alkoxides in ketone hydroboration. Experiments and DFT calculations are suggestive of a concerted reaction pathway traversing through a six-membered transition state involving MgÀ OCHPh 2 , BÀ H, and C=O bonds. Prompted by this hypothesis, we investigated the activity of [Mg(OCHPh 2 ) 2 ] (3), which exhibits turn-over frequency reaching up to 59,400 h À 1 under solvent-free conditions and stability towards C=C, À OH, À NH 2 and À NO 2 . Due to the non-existence of a metal hydride intermediate, such catalytic reactions will not get hindered in the presence of additional reactive functional groups.