Fixation of Dinitrogen at an Asymmetric Binuclear Titanium Complex

A new type of dititanium dinitrogen complex supported by a triphenolamine (TPA) ligand is reported. Analysis by single-crystal X-ray diffraction and Raman and NMR spectroscopy reveals different coordination geometries for the two titanium centers. Hence, coordination of TPA and a nitrogen ligand results in trigonal-bipyramidal geometry, while an octahedral titanium center is obtained upon additional coordination of an ethoxide generated upon C–O bond cleavage in a diethyl ether solvent molecule. The titanium complex successfully generates ammonia in the presence of an excess amount of PCy3HI and KC8 in 154% yield (per titanium atom). A titanium complex with a bulkier TPA does not form a dinitrogen complex, and mononuclear titanium dinitrogen complexes were not accessible, presumably because of the high tendency of early transition metals to form binuclear dinitrogen complexes

<i>N</i>‑Heterocyclic Carbene Nitric Oxide Radicals

<i>N</i>-Heterocyclic carbene-stabilized nitric oxide radicals were prepared by direct addition of nitric oxide to two <i>N</i>-heterocyclic carbenes in solution phase. The compounds were fully characterized by X-ray crystallography and EPR. The nitric oxide moiety in the solid compounds obtained can be thermally transferred to another <i>N</i>-heterocyclic carbene, suggesting potential applications to NO delivery

<i>N</i>‑Heterocyclic Carbene Nitric Oxide Radicals

<i>N</i>-Heterocyclic carbene-stabilized nitric oxide radicals were prepared by direct addition of nitric oxide to two <i>N</i>-heterocyclic carbenes in solution phase. The compounds were fully characterized by X-ray crystallography and EPR. The nitric oxide moiety in the solid compounds obtained can be thermally transferred to another <i>N</i>-heterocyclic carbene, suggesting potential applications to NO delivery