SYNTHESIS AND STRUCTURE OF A TUNGSTEN(IV) ETA-2-DIMETHYLDIAZENE COMPLEX IN WHICH THE DIAZENE LIGAND BEHAVES AS A 4-ELECTRON DONOR

A WCp*Me3(eta(2)-1,2-dimethyldiazene) complex has been synthesized in which the dimethyldiazene behaves as a four-electron donor. A single-crystal X-ray study shows the complex to contain both a short (W-N(1) = 1.860 (8) angstrom) and a long (W-N(2) = 2.126 (7) angstrom) bond characteristic of sp2- and sp3-hybridized nitrogen atoms, respectively, as well as a relatively long N-N bond (1.38 (1) angstrom) characteristic of a reduced 1,2-dimethylhydrazido(2-) ligand. This study illustrates the approximate equivalence of the d(xy) and the d(z)2 orbitals in forming pi-bonds to nitrogen ligands which might be present in a reaction where dinitrogen is reduced to ammonia.