Extension of the nitrosyl-aryldiazo analogy.  Structure of an aryldiazo group coordinated to rhodium in a doubly bent fashion

Gaughan, Arthur P.; Haymore, Barry L.; Ibers, James A.; Myers, William H.; Nappier, Thomas E.; Meek, Devon W.

doi:10.1021/ja00801a070

Cited by 58 publications

(35 citation statements)

References 2 publications

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“…A single N-O stretch band is observed and blueshifts from 1798 to 1843 cm -1 with increasing NO coverage (the value of the N-O stretch frequency in the gas phase is 1860 cm -1 ). A similar range of vibrational frequencies has been reported in the literature for linear iron nitrosyl compounds (Fe-N-O) [56][57][58]. These observations allowed us to attribute the peak in the RAIR spectra to the N-O stretch vibrations when the molecules are adsorbed vertically on Fe ions of the surface while the shift of the peak can be attributed to an increasing influence of lateral intermolecular interactions as the NO coverage increases.…”

Section: Tpdsupporting

confidence: 78%

Fe Oxides on Ag Surfaces: Structure and Reactivity

et al. 2016

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One layer thick iron oxide films are attractive from both applied and fundamental science perspectives. The structural and chemical properties of these systems can be tuned by changing the substrate, making them promising materials for heterogeneous catalysis. In the present work, we investigate the structure of FeO(111) monolayer films grown on Ag(100) and Ag(111) substrates by means of microscopy and diffraction techniques and compare it with the structure of FeO(111) grown on other substrates reported in literature. We also study the NO adsorption properties of FeO(111)/Ag(100) and FeO(111)/Ag(111) systems utilizing different spectroscopic techniques. We discuss similarities and differences in the data obtained from adsorption experiments and compare it with previous results for FeO(111)/Pt(111). Keywords FeO Á Ag Á Surface X-ray diffraction Á Reactivity Á Single crystal surfaces Á Surface structure This article originally listed an author (J. F. Weaver) incorrectly. The article has been updated.

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Section: Tpdsupporting

confidence: 78%

Fe Oxides on Ag Surfaces: Structure and Reactivity

et al. 2016

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“…Assuming that the two TPD states obtained from Fe 3 O 4 (111) correspond to NO bound to Fe 3+ vs Fe 2+ sites, the RAIR spectra suggest that the bonding of NO on these cation sites perturbs the N–O stretch frequency to similar extents. Notably, the N–O stretch frequency of the main peak is only slightly red-shifted from the gas-phase value (1860 cm –1 ) and lies in the same range as that reported for iron nitrosyl compounds in which the NO ligand is bound in a linear geometry on top of an Fe atom. − The RAIR spectra thus suggest that the adsorption of NO on both Fe 2+ and Fe 3+ sites of Fe 3 O 4 (111) involves a slight increase in electron density at the NO molecule due to π-backbonding. Lastly, the appearance of the peak at 1885 cm –1 occurs at coverages at which the NO TPD spectra begin to exhibit peaks below about 170 K. Wilde et al have reported analogous behavior in the adsorption of NO on a Cr 2 O 3 (0001) surface and show that NO dimers are responsible for the weak RAIRS peak near 1885 cm –1 …”

Section: Resultssupporting

confidence: 67%

Adsorption of NO on FeO_x Films Grown on Ag(111)

et al. 2016

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We used temperature-programmed desorption (TPD) and reflection absorption infrared spectroscopy (RAIRS) to characterize the adsorption of NO on crystalline iron oxide films grown on Ag(111), including a Fe3O4(111) layer, an FeO(111) monolayer, and an intermediate FeO x multilayer structure. TPD shows that the NO binding energies vary significantly among the Fe cation sites present on these FeO x surfaces, and provides evidence that NO binds more strongly on Fe2+ sites than Fe3+ sites. The NO TPD spectra obtained from the Fe3O4(111) layer exhibit a dominant peak at 380 K, attributed to NO bound on Fe2+ sites, as well as a broad feature centered at ∼250 K that is consistent with NO bound on Fe3+ sites of Fe3O4(111) as well as NO adsorbed on a minority FeO structure. The NO TPD spectra obtained from the monolayer FeO(111) film exhibits a prominent peak at 269 K. After growing FeO x multilayer islands within the FeO(111) monolayer, we observe a new NO TPD feature at ∼200 K as well as diminution of the sharp TPD peak at 269 K. We speculate that these changes occur because the multilayer FeO x islands expose Fe3+ sites that bind NO more weakly than the Fe2+ sites of the FeO monolayer. RAIR spectra obtained from the NO-covered FeO x surfaces exhibit an N–O stretch band that blueshifts over a range from about 1800 to 1840 cm–1 with increasing NO coverage. The measured N–O stretching frequency is only slightly red-shifted from the gas-phase value, and lies in a range that is consistent with atop, linearly bound NO on the Fe surface sites. In contrast to the NO binding energy, we find that the N–O stretch band is relatively insensitive to the NO binding site on the FeO x surfaces. This behavior suggests that π-backbonding occurs to similar extents among the adsorbed NO species, irrespective of the oxidation state and local structural environment of the Fe surface site.

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“…The presence of strongly p-acidic pap ligand along with the weakly p-acidic tpm as ancillary ligands in the complex framework of 4 3+ has been reflected in the high m(NO) frequency which in turn signifies the nitrosonium character of the coordinated NO [42]. On the other hand the reduced nitrosyl bent geometry (138.0°, sp 2 -hybridization) in 4 2+ as observed earlier in analogous complexes [42][43][44][45][46][47][48][49][50][51][52][87][88][89][90][91]. The one-electron reduced radical species [Ru II (tpm)(pap)(NO Å )] 2+ (4 2+ ) exhibits the EPR spectrum with g = 1.989 (Fig.…”

Section: Resultsmentioning

confidence: 73%