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Title: Conformational explosion: Understanding the complexity of short chain para -dialkylbenzene potential energy surfaces

Abstract

The single-conformation ultraviolet and infrared spectroscopy of three short-chain para-dialkylbenzenes (para-diethylbenzene, para-dipropylbenzene, and para-dibutylbenzene) is reported for the jet-cooled, isolated molecules. The present study builds off previous work on single-chain n-alkylbenzenes, where an anharmonic local mode Hamiltonian method was developed to account for stretch-bend Fermi resonance in the alkyl CH stretch region [D. P. Tabor et al., J. Chem. Phys. 144, 224310 (2016)]. The jet-cooled molecules are interrogated using laser-induced fluorescence (LIF) excitation, fluorescence dip infrared spectroscopy, and dispersed fluorescence. The LIF spectra in the S1 ← S0 origin region show a dramatic increase in the number of resolved transitions with increasing length of the alkyl chains, reflecting an explosion in the number of unique low-energy conformations formed when two independent alkyl chains are present. Since the barriers to isomerization of the alkyl chain are similar in size, this results in an “egg carton” shaped potential energy surface. A combination of electronic frequency shift and alkyl CH stretch infrared spectra is used to generate a consistent set of conformational assignments. Using these experimental techniques in conjunction with computational methods, subsets of origin transitions in the LIF excitation spectrum can be classified into different conformational families. Two conformations are resolved inmore » para-diethylbenzene, seven in para-dipropylbenzene, and about nineteen in para-dibutylbenzene. These chains are largely independent of each other as there are no new single-chain conformations induced by the presence of a second chain. A cursory LIF excitation scan of para-dioctylbenzene shows a broad congested spectrum at frequencies consistent with interactions of alkyl chains with the phenyl π cloud« less

Authors:
 [1]; ORCiD logo [1]; ORCiD logo [1]
  1. Purdue Univ., West Lafayette, IN (United States)
Publication Date:
Research Org.:
Purdue Univ., West Lafayette, IN (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES)
OSTI Identifier:
1512948
Alternate Identifier(s):
OSTI ID: 1436560
Grant/Contract Number:  
FG02-96ER14656
Resource Type:
Accepted Manuscript
Journal Name:
Journal of Chemical Physics
Additional Journal Information:
Journal Volume: 148; Journal Issue: 18; Journal ID: ISSN 0021-9606
Publisher:
American Institute of Physics (AIP)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY

Citation Formats

Mishra, Piyush, Hewett, Daniel M., and Zwier, Timothy S. Conformational explosion: Understanding the complexity of short chain para -dialkylbenzene potential energy surfaces. United States: N. p., 2018. Web. doi:10.1063/1.5029373.
Mishra, Piyush, Hewett, Daniel M., & Zwier, Timothy S. Conformational explosion: Understanding the complexity of short chain para -dialkylbenzene potential energy surfaces. United States. https://doi.org/10.1063/1.5029373
Mishra, Piyush, Hewett, Daniel M., and Zwier, Timothy S. Wed . "Conformational explosion: Understanding the complexity of short chain para -dialkylbenzene potential energy surfaces". United States. https://doi.org/10.1063/1.5029373. https://www.osti.gov/servlets/purl/1512948.
@article{osti_1512948,
title = {Conformational explosion: Understanding the complexity of short chain para -dialkylbenzene potential energy surfaces},
author = {Mishra, Piyush and Hewett, Daniel M. and Zwier, Timothy S.},
abstractNote = {The single-conformation ultraviolet and infrared spectroscopy of three short-chain para-dialkylbenzenes (para-diethylbenzene, para-dipropylbenzene, and para-dibutylbenzene) is reported for the jet-cooled, isolated molecules. The present study builds off previous work on single-chain n-alkylbenzenes, where an anharmonic local mode Hamiltonian method was developed to account for stretch-bend Fermi resonance in the alkyl CH stretch region [D. P. Tabor et al., J. Chem. Phys. 144, 224310 (2016)]. The jet-cooled molecules are interrogated using laser-induced fluorescence (LIF) excitation, fluorescence dip infrared spectroscopy, and dispersed fluorescence. The LIF spectra in the S1 ← S0 origin region show a dramatic increase in the number of resolved transitions with increasing length of the alkyl chains, reflecting an explosion in the number of unique low-energy conformations formed when two independent alkyl chains are present. Since the barriers to isomerization of the alkyl chain are similar in size, this results in an “egg carton” shaped potential energy surface. A combination of electronic frequency shift and alkyl CH stretch infrared spectra is used to generate a consistent set of conformational assignments. Using these experimental techniques in conjunction with computational methods, subsets of origin transitions in the LIF excitation spectrum can be classified into different conformational families. Two conformations are resolved in para-diethylbenzene, seven in para-dipropylbenzene, and about nineteen in para-dibutylbenzene. These chains are largely independent of each other as there are no new single-chain conformations induced by the presence of a second chain. A cursory LIF excitation scan of para-dioctylbenzene shows a broad congested spectrum at frequencies consistent with interactions of alkyl chains with the phenyl π cloud},
doi = {10.1063/1.5029373},
journal = {Journal of Chemical Physics},
number = 18,
volume = 148,
place = {United States},
year = {Wed May 09 00:00:00 EDT 2018},
month = {Wed May 09 00:00:00 EDT 2018}
}

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Figures / Tables:

FIG. 1 FIG. 1: Chemical structures and key dihedral angles for para-diethylbenzene ($p$-dEthB), para-dipropylbenzene ($p$-dPropB), and para-dibutylbenzene ($p$-dButB).

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Works referenced in this record:

State-specific studies of internal mixing in a prototypical flexible bichromophore: Diphenylmethane
journal, September 2008

  • Pillsbury, Nathan R.; Stearns, Jaime A.; Müller, Christian W.
  • The Journal of Chemical Physics, Vol. 129, Issue 11
  • DOI: 10.1063/1.2977730

Aromatic Ring-Forming Reactions of Metastable Diacetylene with 1,3-Butadiene
journal, May 1998

  • Arrington, Caleb A.; Ramos, Christopher; Robinson, Allison D.
  • The Journal of Physical Chemistry A, Vol. 102, Issue 19
  • DOI: 10.1021/jp980648m

An ab Initio Study on the Torsional Surface of Alkanes and Its Effect on Molecular Simulations of Alkanes and a DPPC Bilayer
journal, March 2005

  • Klauda, Jeffery B.; Brooks, Bernard R.; MacKerell, Alexander D.
  • The Journal of Physical Chemistry B, Vol. 109, Issue 11
  • DOI: 10.1021/jp0468096

Mode‐selective photoisomerization in 5‐hydroxytropolone. I. Experiment
journal, April 1995

  • Ensminger, Frederick A.; Plassard, Jason; Zwier, Timothy S.
  • The Journal of Chemical Physics, Vol. 102, Issue 13
  • DOI: 10.1063/1.469250

Supersonic molecular jet spectroscopy of ethylbenzene, the ethyltoluenes, and the diethylbenzenes
journal, September 1987

  • Breen, P. J.; Bernstein, E. R.; Seeman, Jeffrey I.
  • The Journal of Chemical Physics, Vol. 87, Issue 6
  • DOI: 10.1063/1.453019

High-Density Renewable Diesel and Jet Fuels Prepared from Multicyclic Sesquiterpanes and a 1-Hexene-Derived Synthetic Paraffinic Kerosene
journal, March 2015

  • Harvey, Benjamin G.; Merriman, Walter W.; Koontz, Thomas A.
  • Energy & Fuels, Vol. 29, Issue 4
  • DOI: 10.1021/ef5027746

Capillary gas chromatography of aromatic compounds found in coal tar fractions
journal, April 1981


Anharmonic modeling of the conformation-specific IR spectra of ethyl, n -propyl, and n -butylbenzene
journal, June 2016

  • Tabor, Daniel P.; Hewett, Daniel M.; Bocklitz, Sebastian
  • The Journal of Chemical Physics, Vol. 144, Issue 22
  • DOI: 10.1063/1.4953181

Vapor Pressure of Coal Chemicals
journal, October 1983

  • Chao, J.; Lin, C. T.; Chung, T. H.
  • Journal of Physical and Chemical Reference Data, Vol. 12, Issue 4
  • DOI: 10.1063/1.555695

Isolated C–H stretching vibrations of n ‐alkanes: Assignments and relation to structure
journal, December 1984

  • Snyder, Robert G.; Aljibury, A. L.; Strauss, Herbert L.
  • The Journal of Chemical Physics, Vol. 81, Issue 12
  • DOI: 10.1063/1.447677

Macromodel?an integrated software system for modeling organic and bioorganic molecules using molecular mechanics
journal, May 1990

  • Mohamadi, Fariborz; Richards, Nigel G. J.; Guida, Wayne C.
  • Journal of Computational Chemistry, Vol. 11, Issue 4
  • DOI: 10.1002/jcc.540110405

Report on Notation for the Spectra of Polyatomic Molecules
journal, November 1955

  • Mulliken, Robert S.
  • The Journal of Chemical Physics, Vol. 23, Issue 11
  • DOI: 10.1063/1.1740655

The Last Globally Stable Extended Alkane
journal, August 2012

  • Lüttschwager, Nils O. B.; Wassermann, Tobias N.; Mata, Ricardo A.
  • Angewandte Chemie International Edition, Vol. 52, Issue 1
  • DOI: 10.1002/anie.201202894

Identifying the first folded alkylbenzene via ultraviolet, infrared, and Raman spectroscopy of pentylbenzene through decylbenzene
journal, January 2017

  • Hewett, Daniel M.; Bocklitz, Sebastian; Tabor, Daniel P.
  • Chemical Science, Vol. 8, Issue 8
  • DOI: 10.1039/c7sc02027a

Conformationally induced transition moment rotations in the S1←S0 electronic spectra of n-propylbenzene and n-butylbenzene
journal, January 1997

  • A. Dickinson, John; W. Joireman, Paul; T. Kroemer, Romano
  • Journal of the Chemical Society, Faraday Transactions, Vol. 93, Issue 8
  • DOI: 10.1039/a608012j

Works referencing / citing this record:

Broadband rotational spectroscopy of trans 3-pentenenitrile and 4-pentenenitrile
journal, January 2019

  • Mishra, Piyush; Fritz, Sean M.; Hays, Brian M.
  • Physical Chemistry Chemical Physics, Vol. 21, Issue 42
  • DOI: 10.1039/c9cp04328d