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Title: A study of the conformational isomerism of 1-iodobutane by high resolution rotational spectroscopy

Abstract

The first microwave study of 1-iodobutane, performed by Steinmetz et al. in 1977, led to the determination of the B+C parameter for the anti-anti- and gauche-anti-conformers. Nearly 40 years later, in this paper this reinvestigation of 1-iodobutane, by high-resolution microwave spectroscopy, led to the determination of rotational constants, centrifugal distortion constants, nuclear quadrupole coupling constants (NQCCs), and nuclear-spin rotation constants belonging to both of the two previously mentioned conformers, in addition to the gauche-gauche-conformer, which was observed in this frequency regime for the first time. Finally, comparisons between the three conformers of 1-iodobutane and other iodo- and bromoalkanes are made, specifically through an analysis of the nuclear quadrupole coupling constants belonging to the iodine and bromine atoms in the respective chemical environments.

Authors:
; ; ; ;
Publication Date:
Research Org.:
Wesleyan Univ., Middletown, CT (United States); Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org.:
USDOE; National Science Foundation (NSF)
OSTI Identifier:
1349075
Report Number(s):
PNNL-SA-123377
Journal ID: ISSN 0022-2852; PII: S0022285217300346
Grant/Contract Number:
AC05-76RL01830; CHE-1565276; CNS-0619508
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Journal of Molecular Spectroscopy
Additional Journal Information:
Journal Volume: 335; Journal Issue: C; Journal ID: ISSN 0022-2852
Publisher:
Elsevier
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; 74 ATOMIC AND MOLECULAR PHYSICS; Rotational spectroscopy; Nuclear quadrupole coupling tensor; Conformations; Iodine; Haloalkane; FTMW

Citation Formats

Arsenault, Eric A., Obenchain, Daniel A., Blake, Thomas A., Cooke, S. A., and Novick, Stewart E. A study of the conformational isomerism of 1-iodobutane by high resolution rotational spectroscopy. United States: N. p., 2017. Web. doi:10.1016/j.jms.2017.03.014.
Arsenault, Eric A., Obenchain, Daniel A., Blake, Thomas A., Cooke, S. A., & Novick, Stewart E. A study of the conformational isomerism of 1-iodobutane by high resolution rotational spectroscopy. United States. doi:10.1016/j.jms.2017.03.014.
Arsenault, Eric A., Obenchain, Daniel A., Blake, Thomas A., Cooke, S. A., and Novick, Stewart E. 2017. "A study of the conformational isomerism of 1-iodobutane by high resolution rotational spectroscopy". United States. doi:10.1016/j.jms.2017.03.014.
@article{osti_1349075,
title = {A study of the conformational isomerism of 1-iodobutane by high resolution rotational spectroscopy},
author = {Arsenault, Eric A. and Obenchain, Daniel A. and Blake, Thomas A. and Cooke, S. A. and Novick, Stewart E.},
abstractNote = {The first microwave study of 1-iodobutane, performed by Steinmetz et al. in 1977, led to the determination of the B+C parameter for the anti-anti- and gauche-anti-conformers. Nearly 40 years later, in this paper this reinvestigation of 1-iodobutane, by high-resolution microwave spectroscopy, led to the determination of rotational constants, centrifugal distortion constants, nuclear quadrupole coupling constants (NQCCs), and nuclear-spin rotation constants belonging to both of the two previously mentioned conformers, in addition to the gauche-gauche-conformer, which was observed in this frequency regime for the first time. Finally, comparisons between the three conformers of 1-iodobutane and other iodo- and bromoalkanes are made, specifically through an analysis of the nuclear quadrupole coupling constants belonging to the iodine and bromine atoms in the respective chemical environments.},
doi = {10.1016/j.jms.2017.03.014},
journal = {Journal of Molecular Spectroscopy},
number = C,
volume = 335,
place = {United States},
year = 2017,
month = 5
}

Journal Article:
Free Publicly Available Full Text
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  • The first microwave study of 1-iodobutane, performed by Steinmetz et al.in 1977) led to the determination of the B + C parameter for the anti-anti­and gauche-anti-conformers. Nearly 40 years later, this reinvestigation of 1- iodobutane, by high-resolution microwave spectroscopy, led to the determina­tion of rotational constants, centrifugal distortion constants, nuclear quadrupole coupling constants (NQCCs), and nuclear-sp rotation constants belonging to both of the two previously mentioned conformers, in addition to the gauche­ gauche-conformer, which was observed in this frequency regime for the first time. Comparisons between the three conformers of 1-iodobutanc and other iodo- and bromoalkanes are made, specifically throughmore » an analysis of the nuclear quadrupole coupling constants belonging to the iodine and bromine atoms in the respective chemical environments.« less
  • The rotational transitions belonging to 2-iodobutane (sec-butyl-iodide, CH3CHICH2CH3) have been measured over the frequency range 5.5-16.5 GHz via jet-pulsed Fourier transform microwave (FTMW) spectroscopy. The complete nuclear quadrupole coupling tensor of iodine, ¬, has been obtained for the gauche (g)-, anti (a)-, and gauche0 (g0)-conformers, as well as the four 13C isotopologues of the gauche species. Rotational constants, centrifugal distortion constants, quadrupole coupling constants, and nuclear spin-rotation constants were determined for each species. Changes in the ¬ of the iodine nucleus, resulting from conformational and isotopic dierences, will be discussed. Isotopic substitution of g-2-iodobutane allowed for a rs structure tomore » be determined for the carbon backbone. Additionally, isotopic substitution, in conjunction with an ab initio structure, allowed for a t of various r0 structural parameters belonging to g-2-iodobutane.« less
  • High-resolution spectra of the S{sub 1}←S{sub 0} transition in jet-cooled deuterated benzenes were observed using pulse dye amplification of single-mode laser light and mass-selective resonance enhanced multiphoton ionization (REMPI) detection. The vibrational and rotational structures were accurately analyzed for the vibronic levels in the S{sub 1} state. The degenerate 6{sup 1} levels of C{sub 6}H{sub 6} or C{sub 6}D{sub 6} are split into 6a{sup 1} and 6b{sup 1} in many of deuterated benzenes. The rigid-rotor rotational constants were assessed and found to be slightly different between 6a and 6b because of different mean molecular structures. Their rotational levels are significantlymore » shifted by Coriolis interactions. It was found that the Coriolis parameter proportionally changed with the number of substituted D atoms.« less
  • The rotational isomerism of 3-alkyl(aryl)-5-alkyl(aralkyl)hydantoins in which the methylene group of the side chain, together with the methylidyne group in the 5 position of the ring, forms the structure of a substituted ethane was investigated by means of PMR spectroscopy.
  • The first high-resolution study of weakly bound cluster ions is reported. The millimeter- and submillimeter-wave rotational spectra of ArH/sub 3/ /sup +/ and ArD/sub 3/ /sup +/ have been observed in a magnetically confined, liquid-nitrogen--cooled glow discharge and a partial molecular structure has been derived from their analysis. ArH/sub 3/ /sup +/ appears to be planar, with the Ar atom lying on a symmetry axis of the H/sub 3/ /sup +/ equilateral triangle, 2.38 A from the H/sub 3/ /sup +/ centroid. SPlitting of some of the lines is strong evidence for tunneling motion.