Steric control of Mg-Mg bond formation N activation in the reduction of bulky magnesium diamide complexes.

Reduction of the magnesium(II) diamide [Mg(NON)] (NON = 4,5-bis(2,4,6-triisopropylanilido)-2,7-diethyl-9,9-dimethyl-xanthene) with 5% w/w K/KI leads to a good yield of a dianionic dimagnesium(I) species, as its potassium salt, [{K(NON)Mg}]. An X-ray crystallographic analysis shows the molecule to contain a very long Mg-Mg bond (3.137(2) Å). The formation of [{K(NON)Mg}] contrasts with a previously reported reduction of a magnesium(II) complex incorporating a bulkier diamide ligand, which instead afforded a magnesium-dinitrogen complex. In the current study, [{K(NON)Mg}] has been shown to be a viable reagent for the reductive activation of CO, H and NO.