Molecular N2 complexes of iron stabilised by N-heterocyclic pincer dicarbene ligands

The first N2 complex stabilised by N-heterocyclic carbene ligands, Fe(C-N-C)(N2)2, has been obtained by the reduction of Fe(C-N-C)Br2 where C-N-C = 2,6-bis(aryl-imidazol-2-ylidene)pyridine, aryl = 2,6-Pri2C6H3, with Na(Hg); it serves as a convenient precursor for other iron NHC ʹpincerʹ complexes of the type Fe(C-N-C)(N2)L where L = C2H4, PMe3 and Fe(C-N-C)(CO)2.