University of Illinois Urbana-Champaign

Infrared spectroscopy of Zn(acetylene)1−5+: Evidence of acetylene activation by a metal radical

Marks, Joshua H

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1103936.pptx
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https://hdl.handle.net/2142/100835

Description

Title
Infrared spectroscopy of Zn(acetylene)1−5+: Evidence of acetylene activation by a metal radical
Author(s)
Marks, Joshua H
Contributor(s)
  • Duncan, Michael A.
  • Ward, Timothy B.
Issue Date
2018-06-22
Keyword(s)
Ions
Date of Ingest
  • 2018-08-17T16:09:52Z
  • 2018-12-12T22:37:56Z
Abstract
Zinc cation is studied as a model system for single atom catalysis in the gas phase with infrared photodissociation spectroscopy. Zn(C2H2)n + (n = 1–5) clusters are produced via laser vaporization of zinc in a supersonic expansion of acetylene and argon. Clusters are mass-selected and studied with infrared photodissociation spectroscopy in the C–H stretching region. Smaller clusters (n = 1–3) are studied with the use of a weakly bound argon tag. These spectra are assigned with B3LYP/Def2TZVP computational studies. Zn(C2H2) + is found to consist of a C2v three membered metallacycle, where zinc is equidistant from both carbon atoms of acetylene. Zn(C2H2)2 + does not contain a metallacycle, but features zinc binding more closely to one of the carbon atoms of each acetylene in a C2 configuration. The three-coordinate cluster is predicted to be lowest in energy as a π-bound D3h structure, with a low energy C3 structure. When the spectrum of this cluster is measured with argon tagging the D3h isomer is most abundant. When measured without the tag the C3 isomer is found to be in abundance. The spectra of the four and five coordinate clusters are found to contain a feature 160 cm−1 to the red of the acetylene C–H asymmetric stretch. This is attributed to a fourth acetylene ligand forming a metal vinyl radical, accompanied by formation of Zn(II). This transfer of the radical center from zinc to a ligand activates the acetylene, and could be the first step in single atom catalysis by zinc.
Publisher
International Symposium on Molecular Spectroscopy
Type of Resource
text
Genre of Resource
Conference Paper / Presentation
Language
eng
Permalink
http://hdl.handle.net/2142/100835
DOI
10.15278/isms.2018.FE06
Copyright and License Information
Copyright 2018 Joshua H. Marks

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Abstracts & Presentations - 2018 International Symposium on Molecular Spectroscopy PRIMARY