Anion Photoelectron Spectroscopic Studies Of The Nbc4h4−, Nbc6h6− And Nbc6h4− Products Of Flow Tube Reactions Of Niobium With Butadiene

Baudhuin, Melissa A.

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https://hdl.handle.net/2142/50921 Copy

Description

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

Issue Date

2014-06-17

Keyword(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.

Publisher

International Symposium on Molecular Spectroscopy

Type of Resource

text

Language

English

Permalink

http://hdl.handle.net/2142/50921

DOI

https://doi.org/10.15278/isms.2014.TK15

Copyright and License Information

Copyright 2014 by the authors. Licensed under a Creative Commons Attribution 4.0 International License. http://creativecommons.org/licenses/by/4.0/

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