Publications [#232723] of Katherine J. Franz

Journal Articles

  1. Franz, KJ; Lippard, SJ, "NO disproportionation reactivity of Fe tropocoronand complexes", Journal of the American Chemical SocietyNovember,, 1999, 121(45), 10504-10512, American Chemical Society (ACS) [doi].
    (last updated on 2023/01/01)

    Abstract:
    The synthesis and characterization of divalent [Fe(TC-5,5)] (1) and trivalent [Fe(OTf)(TC-5,5)] (2) tropocoronand complexes are described. Compound 1 reacts with 1 equiv of NO to form the {FeNO}7 complex 3. A single-crystal X-ray structure determination of 3 reveals a trigonal bipyramidal geometry with a linearly coordinated nitrosyl (Fe-N-O = 174.3(4)°) having a short Fe-N distance of 1.670(4) Å. EPR and Mossbauer spectroscopy, SQUID susceptometry, and normal coordinate analysis indicate 3 to be a low-spin {Fe(III)(NO-)}2+ species. In the presence of excess NO, 3 converts to a metastable nitrosyl-nitrito complex that decomposes by losing NO2, which subsequently nitrates the aromatic tropolone rings of the ligand. The final products of the NO disproportionation reaction are N2O and [Fe(NO)(TC-5,5-NO2)] (4). The v(NO) stretching band of 4 is increased to 1716 cm-1 from its value of 1692 cm-1 in 3, owing to the electron- withdrawing nitro groups on the ligand, and the compound no longer promotes the disproportionation of NO. Mechanistic aspects of the reaction are discussed.