Steric control of Mg-Mg bond formation vs. N 2 activation in the reduction of bulky magnesium diamide complexes.

Reduction of the magnesium(II) diamide [Mg( Trip NON)] ( Trip 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( Trip NON)Mg} 2 ]. An X-ray crystallographic analysis shows the molecule to contain a very long Mg-Mg bond (3.137(2) Å). The formation of [{K( Trip NON)Mg} 2 ] 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( Trip NON)Mg} 2 ] has been shown to be a viable reagent for the reductive activation of CO, H 2 and N 2 O.