Cationic magnesium hydride [MgH]+ stabilized by an NNNN-type macrocycle.

A magnesium hydride cation [(L)MgH]+ supported by a macrocyclic ligand (L = Me4TACD; 1,4,7,10-tetramethyl-1,4,7,10-tetraazacyclododecane) has been prepared by partial protonolysis of a mixed amide hydride [(L)MgH2Mg{N(SiMe3)2}2] and shown to undergo a variety of reactions with unsaturated substrates, including pyridine.