Dimethylmagnesium revisited

Abstract

A compilation of solvent-free homometallic methyl compounds of the type MMe_x (x = 1–6) is provided and categorised according to their method of characterisation (powder or single crystal X-ray diffraction, gas electron diffraction (GED), reactivity, unconfirmed). Recrystallisation of polymeric [MgMe₂]_n from excess GaMe₃ led to the formation of highly pure [MgMe₂]_n suitable for single crystal X-ray crystallographic studies. Transient Mg(GaMe₄)₂ could be detected in excess GaMe₃ by NMR spectroscopy, but its isolation as Mg(GaMe₄)₂ failed. On one occasion tetrameric [Mg(GaMe₄)(OMe)]₄ could be isolated as a minor co-product. The formation of single-crystalline [MgMe₂]_n from a saturated ethereal solution could be reproduced as reported earlier by Coates et al. Assessing the reactivity of potassium methoxide methanol adduct toward Mg(AlMe₄)₂, the protonolysis reaction with MeOH gave unprecedented [Mg(AlMe₄){Al(OMe)₂Me₂}]₂ featuring one 8-membered [MgOAlO]₂ metalloxane ring and two 4-membered metallacycles.