Inorganic Chemistry, Vol.38, No.2, 243-252, 1999
Heterobimetallic dinitrogen complexes that contain the {[N3N]Mo-N=N)(-) ligand
{[N3N]Mo-N=N}(2)Mg(THF)(2) reacts with FeCl2 at -20 degrees C in a mixture of ether, THF, and toluene to yield paramagnetic {[N3N]Mo-N=N}(3)Fe (1), an X-ray study of which shows it to contain iron in a trigonal planar environment. X-band ESR, iron-57 Mossbauer 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}(2)Fe(DMPE) (2). SQUID magnetic susceptibility and Mossbauer data are in accord with formulation of 2 as a high-spin Fe(II) complex. {[N3N]Mo-N=N}(2)Mg(THF)(2) reacts with VCl4(DME) and VCl3(THF)(3) in THF to give paramagnetic {[N3N]Mo-N=N}(3)VCl (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)(2)VCl(THF) (4). Several zirconium/molybdenum dinitrogen complexes have been prepared by the reaction between {[N3N]Mo-N=N})(2)Mg(THF)(2) and ZrCl4(THF)(2), and {[N3N]Mo-N=N}(2)ZrCl2 has been characterized by X-ray crystallography.
Keywords:X-RAY STRUCTURE;ALKYL COMPLEXES;IRON COMPLEXES;FIXATION;CHEMISTRY;NITROGENASE;MOLYBDENUM;OXIDATION;VANADIUM;M=TI