Heterobimetallic Dinitrogen Complexes That Contain the {[N₃N]Mo−NN}^- Ligand

{[N3N]Mo−NN}2Mg(THF)2 reacts with FeCl2 at −20 °C in a mixture of ether, THF, and toluene to yield paramagnetic {[N3N]Mo−NN}3Fe (1), an X-ray study of which shows it to contain iron in a trigonal planar environment. X-band ESR, iron-57 Mössbauer spectroscopy, and magnetic susceptibility studies of 1 confirm that it contains high-spin Fe(III) in an anisotropic magnetic environment. Addition of DMPE to toluene solutions of 1 results in loss of [N3N]MoN2 from the coordination sphere to give {[N3N]Mo−NN}2Fe(DMPE) (2). SQUID magnetic susceptibility and Mössbauer data are in accord with formulation of 2 as a high-spin Fe(II) complex. {[N3N]Mo−NN}2Mg(THF)2 reacts with VCl4(DME) and VCl3(THF)3 in THF to give paramagnetic {[N3N]Mo−NN}3VCl (3) in 28−42% yield. A second paramagnetic complex is also produced in these reactions and has been identified by X-ray crystallography as {[N3N]Mo−NN}2VCl(THF) (4). Several zirconium/molybdenum dinitrogen complexes have been prepared by the reaction between {[N3N]Mo−NN}2Mg(THF)2 and ZrCl4(THF)2, and {[N3N]Mo−NN}2ZrCl2 has been characterized by X-ray crystallography.