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Title:Anion Photoelectron Spectroscopic Studies Of The Nbc4h4−, Nbc6h6− And Nbc6h4− Products Of Flow Tube Reactions Of Niobium With Butadiene
Author(s):Baudhuin, Melissa A.
Contributor(s):Miller, Stephen R; Leopold, Doreen; Schnepper, D. Alex; Boopalachandran, Praveenkumar
Subject(s):Metal containing
Abstract:We report mass spectra, 488 nm anion photoelectron spectra, and density functional theory (DFT) calculations of organometallic complexes produced by flow tube reactions of niobium with butadiene (C$_{4}$H$_{6}$), and compare these results with those obtained upon reactions with ethylene (C$_{2}$H$_{4}$). In the C$_{4}$H$_{6}$ experiments, NbC$_{4}$H$_{4}$$^{-}$ is the most abundant product anion, indicating loss of H$_{2}$ upon reaction with Nb. DFT analysis of the vibrationally-resolved photoelectron spectrum indicates that the $^{3}$A$^\prime$ anion incorporates a five-membered Nb-C$_{4}$ ring in which the Nb atom lies outside the C$_{4}$ plane. The electron affinity of the corresponding neutral molecule ($^{2}$A$^\prime$) is measured to be 0.997 $\pm$ 0.006 eV. Upon reaction with C$_{2}$H$_{4}$, at least one additional isomer of NbC$_{4}$H$_{4}$$^{-}$ is produced, giving rise to broad spectral features at higher electron binding energies. Reactions with C$_{4}$H$_{6}$ also yield relatively small amounts of the NbC$_{6}$H$_{6}$$^{-}$ and NbC$_{6}$H$_{4}$$^{-}$ product anions, indicating C-C bond activation in addition to dehydrogenation. The former anion displays the $^{3}$A$_{1}$, C$_{6v}$ Nb-benzene $\pi$-complex structure previously observed upon reaction with C$_{2}$H$_{4}$. The NbC$_{6}$H$_{4}$$^{-}$ anion produced upon reaction with C$_{4}$H$_{6}$ yields at least two vibrationally-resolved photodetachment transitions. DFT calculations performed to date suggest that the lower electron binding energy transition, which indicates an electron affinity of 1.110 $\pm$ 0.008 eV for the corresponding neutral complex, is due to the $^{4}$B$_{2}$ $\leftarrow$ $^{3}$B$_{2}$ detachment from a planar, C$_{2v}$ Nb-benzyne anion.
Issue Date:2014-06-17
Publisher:International Symposium on Molecular Spectroscopy
Citation Info:Baudhuin, M.A.; Miller, S.R.; Leopold, D.; Schnepper, D.A.; Boopalachandran, P. ANION PHOTOELECTRON SPECTROSCOPIC STUDIES OF THE NbC4H4−, NbC6H6− AND NbC6H4− PRODUCTS OF FLOW TUBE REACTIONS OF NIOBIUM WITH BUTADIENE. Proceedings of the International Symposium on Molecular Spectroscopy, Urbana, IL, June 16-21, 2014. DOI: 10.15278/isms.2014.TK15
Rights Information:Copyright 2014 by the authors. Licensed under a Creative Commons Attribution 4.0 International License.
Date Available in IDEALS:2014-09-17

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