Conformational studies of 1-octyne from rotational spectroscopy

Melchreit, Robert

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https://hdl.handle.net/2142/97019 Copy

Description

Title

Conformational studies of 1-octyne from rotational spectroscopy

Author(s)

Melchreit, Robert

Contributor(s)

• Novick, Stewart E.
• Cooke, S.A.
• Obenchain, Daniel A.
• Maturo, Mark P.

Issue Date

2017-06-20

Keyword(s)

Structure determination

Abstract

Alkanes of the form chem{CH_3(CH_2)_nCH_3} generally favor ground state geometries that have co-planar carbon atoms. In this study, we have looked at a long chain hydrocarbon with a terminal carbon-carbon triple bond, emph{viz}., 1-octyne. Guided by the results of the 1-hexyne studies,footnote{Atticks, K.; Bohn, R. K.; Michaels H. H. Int’l J. of Quantum Chem. 2001, 85, 514-519; Utzat, K.; Bohn, R. K.; Michaels H. H. J. Mol. Struct. 2007, 841, 22-27} three possible low energy conformers were studied which we reference as anti-anti (AA, straight chain), anti-gauche (AG, terminal methyl group is gauche), and gauche-anti (GA, ethyl group is gauche). An initial broadband chirp-pulse was performed between 7-13 GHz and a total of sixty-eight transitions were fit. Additional measurements on a Balle Flygare cavity instrument yielded an additional seventy-three lines belonging to three of the conformers. Transitions for all 8 of the singly substituted $^{13}$C isotopologues, in natural abundance, have also been observed for the AA conformer. emph{Ab-initio} optimizations at the MP2/6-311++g(2d,2p) level of theory and basis set for these three conformers will be compared to experimental rotational constants. Structure determinations of the AA conformer will also be discussed.

Publisher

International Symposium on Molecular Spectroscopy

Type of Resource

text

Language

eng

Permalink

http://hdl.handle.net/2142/97019

DOI

https://doi.org/10.15278/isms.2017.TC02

Copyright and License Information

Copyright 2017 Robert Melchreit

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