1
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Jean DR, Wood SA, Esselman BJ, Woods RC, McMahon RJ. Rotational Spectroscopy of 1-Cyano-2-methylenecyclopropane (C 5H 5N)─A Newly Synthesized Pyridine Isomer. J Phys Chem A 2024; 128:1427-1437. [PMID: 38354365 DOI: 10.1021/acs.jpca.3c08002] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2024]
Abstract
The gas-phase rotational spectrum of 1-cyano-2-methylenecyclopropane (C1, C5H5N), an isomer of pyridine, is presented for the first time, covering the range from 235 to 500 GHz. Over 3600 a-, b-, and c-type transitions for the ground vibrational state have been assigned, measured, and least-squares fit to partial-octic A- and S-reduced distorted-rotor Hamiltonians with low statistical uncertainty (σfit = 42 kHz). Transitions for the two lowest-energy fundamental states (ν27 and ν26) and the lowest-energy overtone (2ν27) have been similarly measured, assigned, and least-squares fit to single-state Hamiltonians. Computed vibration-rotation interaction constants (B0-Bv) using the B3LYP and MP2 levels of theory are compared with the corresponding experimental values. Based upon our preliminary analysis, the next few vibrationally excited states form one or more complex polyads of interacting states via Coriolis and anharmonic coupling. The spectroscopic constants and transition frequencies presented here form the foundation for both future laboratory spectroscopy and astronomical searches for 1-cyano-2-methylenecyclopropane.
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Affiliation(s)
- Dairen R Jean
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706-1322, United States
| | - Samuel A Wood
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706-1322, United States
| | - Brian J Esselman
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706-1322, United States
| | - R Claude Woods
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706-1322, United States
| | - Robert J McMahon
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706-1322, United States
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2
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Møllendal H, Samdal S, Guillemin JC. Microwave and Quantum Chemical Study of Intramolecular Hydrogen Bonding in 2-Propynylhydrazine (HC≡CCH2NHNH2). J Phys Chem A 2016; 120:4071-8. [PMID: 27196111 DOI: 10.1021/acs.jpca.6b03796] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The microwave spectrum of 2-propynylhydrazine (HC≡CCH2NHNH2) was investigated in the 23-124 GHz spectral interval. The spectra of two conformers denoted I and II were assigned. I is the lower-energy form, and relative intensity measurements yielded an internal energy difference of 3.0(4) kJ/mol between I and II. The spectra of the ground and five vibrationally excited states were assigned for I, whereas only the spectrum of the ground vibrational state was assigned for II. Both I and II are each stabilized simultaneously by two intramolecular hydrogen bonds. The first of these hydrogen bonds is formed between the hydrogen atom of the -NH- part of the hydrazino group, and the second internal hydrogen bond is formed between one of the hydrogen atoms of the -NH2 part. The π-electrons of the triple bond is thus shared by these two hydrogen atoms. The shortest contact between a hydrogen atom of the hydrazino group and the π-electrons of the ethynyl group is found in lower-energy conformer I. The conformational properties of 2-propynylhydrazine were explored by MP2/cc-pVTZ and CCSD/cc-pVQZ calculations. The CCSD method predicts that seven rotameric forms exist for this compound. Five of these rotamers are stabilized by internal hydrogen bonding. The simultaneous sharing of the π-electrons of the triple bond by two hydrogen atoms occurs only in Conformers I and II, which are predicted to be the two forms with the lowest energies, with I 2.52 kJ/mol lower in energy than II. The effective rotational constants of the ground vibrational states of I and II were predicted by a combination of MP2 and CCSD calculations, whereas centrifugal distortion constants and vibration-rotation constants were calculated by the MP2 method. The theoretical spectroscopic constants are compared with the experimental counterparts. It is concluded that more refined calculations are necessary to obtain complete agreement.
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Affiliation(s)
- Harald Møllendal
- Centre for Theoretical and Computational Chemistry, Department of Chemistry, University of Oslo , P.O. Box 1033, Blindern, NO-0315 Oslo, Norway
| | - Svein Samdal
- Centre for Theoretical and Computational Chemistry, Department of Chemistry, University of Oslo , P.O. Box 1033, Blindern, NO-0315 Oslo, Norway
| | - Jean-Claude Guillemin
- Institut des Sciences Chimiques de Rennes, École Nationale Supérieure de Chimie de Rennes, CNRS, UMR 6226 , 11 Allée de Beaulieu, CS 50837, 35708 Rennes Cedex 7, France
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3
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Møllendal H, Samdal S, Guillemin JC. Microwave and Quantum Chemical Study of Intramolecular Hydrogen Bonding in 2-Propenylhydrazine (H2C═CHCH2NHNH2). J Phys Chem A 2016; 120:407-16. [PMID: 26696467 DOI: 10.1021/acs.jpca.5b11141] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The microwave spectrum of 2-propenylhydrazine (H2C═CHCH2NHNH2) was studied in the 12-61 and 72-123 GHz spectral regions. A variety of intramolecular hydrogen bonds between one or more of the hydrogen atoms of the hydrazino group and the π-electrons are possible for this compound. Assignments of the spectra of four conformers, all of which are stabilized with intramolecular hydrogen bonds are reported. One hydrogen bond exists in two of these conformers, whereas the π-electrons are shared by two hydrogen atoms in the two other rotamers. Vibrationally excited-state spectra were assigned for three of the four conformers. The internal hydrogen bonds are weak, probably in the 3-6 kJ/mol range. A total of about 4400 transitions were assigned for these four forms. The microwave work was guided by quantum chemical calculations at the B3LYP/cc-pVTZ and CCSD/cc-pVTZ levels of theory. These calculations indicated that as many as 18 conformers may exist for 2-propenylhydrazine and 11 of these have either one or two intramolecular hydrogen bonds. The four conformers detected in this work are among the rotamers with the lowest CCSD electronic energies. The CCSD method predicts rotational constants that are very close to the experimental rotational constants. The B3LYP calculations yielded quartic centrifugal distortion constants that deviated considerably from their experimental counterparts in most cases. The calculation of vibration-rotation constants and sextic centrifugal distortion constants by the B3LYP method were generally found to be in poor agreement with the corresponding experimental constants.
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Affiliation(s)
- Harald Møllendal
- Centre for Theoretical and Computational Chemistry (CTCC), Department of Chemistry, University of Oslo , P.O. Box 1033 Blindern, NO-0315 Oslo, Norway
| | - Svein Samdal
- Centre for Theoretical and Computational Chemistry (CTCC), Department of Chemistry, University of Oslo , P.O. Box 1033 Blindern, NO-0315 Oslo, Norway
| | - Jean-Claude Guillemin
- Institut des Sciences Chimiques de Rennes, École Nationale Supérieure de Chimie de Rennes, CNRS , UMR 6226, 11 Allée de Beaulieu, CS 50837, 35708 Rennes Cedex 7, France
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4
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Thankachan AP, Sindhu KS, Krishnan KK, Anilkumar G. Recent advances in the syntheses, transformations and applications of 1,1-dihalocyclopropanes. Org Biomol Chem 2015; 13:8780-802. [PMID: 26173173 DOI: 10.1039/c5ob01088h] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
gem-Dihalocyclopropanes have wide-spread applications in organic synthesis due to their versatile chemistry. They can serve as substrates for a large range of useful materials such as natural products, alkaloids, cyclopropanes, heterocycles, aromatic ring systems etc. Normally the dihalocyclopropanes are prepared by the addition of dihalocarbene to alkene, but due to the great synthetic efficacy of gem-dihalocyclopropanes a number of methods have been developed for their synthesis. Generally gem-dihalocyclopropanes exist as strained cyclic systems with astonishing kinetic stability. They are capable of undergoing transformations leading to a variety of products which have potential applications in various synthetic organic chemistry fields.
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Affiliation(s)
- Amrutha P Thankachan
- School of Chemical Sciences, Mahatma Gandhi University, PD Hills P. O., Kottayam, Kerala, India 686560.
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5
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Møllendal H, Samdal S, Guillemin JC. Microwave and Quantum Chemical Study of the Hydrazino Group as Proton Donor in Intramolecular Hydrogen Bonding of (2-Fluoroethyl)hydrazine (FCH2CH2NHNH2). J Phys Chem A 2015; 119:9252-61. [PMID: 26258892 DOI: 10.1021/acs.jpca.5b06095] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The microwave spectrum of (2-fluoroethyl)hydrazine (FCH2CH2NHNH2) was studied in the 11-123 GHz spectral region to investigate the ability of the hydrazino group to form intramolecular hydrogen bonds acting as a proton donor. This group can participate both in five-member and in six-member internal hydrogen bonds with the fluorine atom. The spectra of four conformers were assigned, and the rotational and centrifugal distortion constants of these rotameric forms were determined. Two of these conformers have five-member intramolecular hydrogen bonds, while the two other forms are without this interaction. The internal hydrogen bonds in the two hydrogen-bonded forms are assumed to be mainly electrostatic in origin because the N-H and C-F bonds are nearly parallel and the associated bond moments are antiparallel. This is the first example of a gas-phase study of a hydrazine where the hydrazino functional group acts as a proton donor in weak intramolecular hydrogen bonds. Extensive quantum chemical calculations at the B3LYP/cc-pVTZ, MP2/cc-pVTZ, and CCSD/cc-pVQZ levels of theory accompanied and guided the experimental work. These calculations predict the existence of no less than 18 conformers, spanning a CCSD internal energy range of 15.4 kJ/mol. Intramolecular hydrogen bonds are predicted to be present in seven of these conformers. Three of these forms have six-member hydrogen bonds, while four have five-member hydrogen bonds. The three lowest-energy conformers have five-member internal hydrogen bonds. The spectrum of the conformer with the lowest energy was not assigned because it has a very small dipole moment. The CCSD relative energies of the two hydrogen-bonded rotamers whose spectra were assigned are 1.04 and 1.62 kJ/mol, respectively, whereas the relative energies of the two conformers with assigned spectra and no hydrogen bonds have relative energies of 6.46 and 4.89 kJ/mol.
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Affiliation(s)
- Harald Møllendal
- Centre for Theoretical and Computational Chemistry (CTCC), Department of Chemistry, University of Oslo, Blindern , P.O. Box 1033, NO-0315 Oslo, Norway
| | - Svein Samdal
- Centre for Theoretical and Computational Chemistry (CTCC), Department of Chemistry, University of Oslo, Blindern , P.O. Box 1033, NO-0315 Oslo, Norway
| | - Jean-Claude Guillemin
- Institut des Sciences Chimiques de Rennes, École Nationale Supérieure de Chimie de Rennes, CNRS, UMR 6226 , 11 Allée de Beaulieu, CS 50837, 35708 Rennes Cedex 7, France
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6
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Samdal S, Møllendal H, Guillemin JC. Conformational properties of cis- and trans-N-Cyclopropylformamide studied by microwave spectroscopy and quantum chemical calculations. J Phys Chem A 2015; 119:3375-83. [PMID: 25772313 DOI: 10.1021/acs.jpca.5b00542] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The microwave spectra of cis- and trans-N-cyclopropylformamide, C3H5NHC(═O)H, have been investigated in the 31-123 GHz spectral region at room temperature. Rotational isomerism about the Cring-N bond is possible for both cis and trans. MP2/cc-pVTZ and CCSD/cc-pVTZ calculations indicate that there are two conformers in the case of cis, called Cis I and Cis II, while only one rotamer, denoted Trans, exists for trans-N-cyclopropylformamide. The quantum chemical methods predict that Cis I has an electronic energy that is 8-9 kJ/mol higher than the energy of Cis II. The CCSD H-Cring-N-H dihedral angle is 0.0° in Cis I, 93.0° in Cis II and 79.9° in Trans. The CCSD and MP2 calculations predict a slightly nonplanar structure for the amide moiety in both Trans and Cis II, whereas Cis I is computed to have a planar amide group bisecting the cyclopropyl ring. Surprisingly, the MP2 and CCSD methods predict practically the same energy for Trans and Cis II. The spectra of Cis II in the ground state and in two vibrationally excited states were assigned, while the spectrum of Cis I was not found presumably because of a low Boltzmann population due to a relatively large energy difference (8-9 kJ/mol). The spectra of the ground vibrational state and seven vibrationally excited states of Trans, were assigned. Vibrational frequencies of several of the excited state of both Cis II and Trans were determined by relative intensity measurements. The experimental and CCSD rotational constants are in satisfactory agreement. The MP2 values of the quartic centrifugal distortion constants of both species are in relatively poor agreement with their experimental counterparts. The MP2 vibration-rotation constants and sextic centrifugal distortion constants have little resemblance with the corresponding experimental values.
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Affiliation(s)
- Svein Samdal
- †Centre for Theoretical and Computational Chemistry (CTCC), Department of Chemistry, University of Oslo, P.O. Box 1033 Blindern, NO-0315 Oslo, Norway
| | - Harald Møllendal
- †Centre for Theoretical and Computational Chemistry (CTCC), Department of Chemistry, University of Oslo, P.O. Box 1033 Blindern, NO-0315 Oslo, Norway
| | - Jean-Claude Guillemin
- ‡Institut des Sciences Chimiques de Rennes, École Nationale Supérieure de Chimie de Rennes, CNRS, UMR 6226, 11 Allée de Beaulieu, CS 50837, 35708 Rennes Cedex 7, France
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7
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Møllendal H, Samdal S, Guillemin JC. Microwave and quantum-chemical study of conformational properties and intramolecular hydrogen bonding of 2-hydroxy-3-butynenitrile (HC≡CCH(OH)C≡N). J Phys Chem A 2015; 119:634-40. [PMID: 25560047 DOI: 10.1021/jp5112923] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The microwave spectra of 2-hydroxy-3-butynenitrile, HC≡CCH(OH)C≡N, and a deuterated species, HC≡CCH(OD)C≡N, have been investigated in the 38-120 GHz spectral region. Three rotameric forms, each stabilized by intramolecular hydrogen bonds, are possible for this compound. The hydrogen atom of the hydroxyl group is hydrogen-bonded to the π electrons of the alkynyl group in one of these conformers, to the π electrons of the cyano group in the second rotamer, and to both of these groups simultaneously in the third conformer. The microwave spectra of the parent and deuterated species of last-mentioned form have been assigned, and accurate values of the rotational and quartic centrifugal distortion constants of these species have been determined. The spectra of two vibrational excited states of this conformer have also been assigned, and their frequencies have been determined by relative intensity measurements. Quantum-chemical calculations at the MP2/cc-pVTZ and CCSD/cc-pVQZ levels were performed to assist the microwave work. The theoretical predictions were generally found to be in good agreement with observations.
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Affiliation(s)
- Harald Møllendal
- Centre for Theoretical and Computational Chemistry (CTCC), Department of Chemistry, University of Oslo , P.O. Box 1033 Blindern, NO-0315 Oslo, Norway
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8
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Samdal S, Møllendal H, Guillemin JC. Synthesis, Microwave Spectrum, Quantum Chemical Calculations, and Conformational Composition of the Novel Compound Cyclopropylethylidynephosphine (C3H5CH2C≡P). J Phys Chem A 2014; 118:9994-10001. [DOI: 10.1021/jp508411z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Svein Samdal
- Centre
for Theoretical and Computational Chemistry (CTCC), Department of
Chemistry, University of Oslo, P.O. Box 1033, Blindern, NO-0315 Oslo, Norway
| | - Harald Møllendal
- Centre
for Theoretical and Computational Chemistry (CTCC), Department of
Chemistry, University of Oslo, P.O. Box 1033, Blindern, NO-0315 Oslo, Norway
| | - Jean-Claude Guillemin
- Institut
des Sciences
Chimiques de Rennes, École Nationale Supérieure de Chimie
de Rennes, CNRS, UMR 6226, 11 Allée
de Beaulieu, CS 50837, 35708 Rennes Cedex 7, France
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9
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Møllendal H, Samdal S, Gauss J, Guillemin JC. Synthesis, Microwave Spectrum, Quantum Chemical Calculations, and Conformational Composition of a Novel Primary Phosphine, Cyclopropylethynylphosphine, (C3H5C≡CPH2). J Phys Chem A 2014; 118:9419-28. [DOI: 10.1021/jp506169g] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Harald Møllendal
- Centre for Theoretical
and Computational Chemistry (CTCC), Department of Chemistry, University of Oslo, P.O.
Box 1033, Blindern, NO-0315 Oslo, Norway
| | - Svein Samdal
- Centre for Theoretical
and Computational Chemistry (CTCC), Department of Chemistry, University of Oslo, P.O.
Box 1033, Blindern, NO-0315 Oslo, Norway
| | - Jürgen Gauss
- Institut für
Physikalische Chemie, Universität Mainz, Duesbergweg 10-14, 55128 Mainz, Germany
| | - Jean-Claude Guillemin
- Institut
des Sciences
Chimiques de Rennes, École Nationale Supérieure de Chimie
de Rennes, CNRS, UMR 6226, 11 Allée de Beaulieu, CS 50837 35708 Rennes Cedex
7, France
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10
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Møllendal H, Samdal S, Guillemin JC. Microwave Spectrum and Conformational Composition of (Azidomethyl)cyclopropane (C 3H 5CH 2N 3). J Phys Chem A 2014; 118:6971-8. [DOI: 10.1021/jp506261a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Harald Møllendal
- Centre
for Theoretical and Computational Chemistry (CTCC), Department of
Chemistry, University of Oslo, Blindern, NO-0315 Oslo, Norway
| | - Svein Samdal
- Centre
for Theoretical and Computational Chemistry (CTCC), Department of
Chemistry, University of Oslo, Blindern, NO-0315 Oslo, Norway
| | - Jean-Claude Guillemin
- Institut
des Sciences Chimiques de Rennes, École Nationale Supérieure de Chimie de Rennes, CNRS,
UMR 6226, 11 Allée de Beaulieu,
CS 50837, 35708 Rennes Cedex 7, France
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11
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Møllendal H, Samdal S, Guillemin JC. Microwave spectrum and intramolecular hydrogen bonding of 2-isocyanoethanol (HOCH(2)CH(2)N≡C). J Phys Chem A 2014; 118:3120-7. [PMID: 24694084 DOI: 10.1021/jp502212n] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The microwave spectrum of 2-isocyanoethanol (HOCH2CH2NC) has been investigated in the 12-120 GHz spectral range. The assignment of this spectrum was severely complicated by the rapid transformation of 2-isocyanoethanol into its isomer 2-oxazoline, which has a rich and strong spectrum. This process appeared both in a gold-plated microwave cell and in a brass cell and is presumed to be catalyzed by metals or traces of base. The spectrum of one conformer was ultimately assigned. This form is stabilized by an intramolecular hydrogen bond between the hydroxyl group and the isocyano group and is the first gas-phase study ever of this kind of hydrogen bonding. The distance between the hydrogen atom of the hydroxyl group and the nitrogen and carbon atoms are as long as 256 and 298 pm, respectively, indicating that covalent contribution to the hydrogen bond is minimal. Electrostatic forces are much more important because the O-H and N≡C bonds are almost parallel and the corresponding bond moments are practically antiparallel. The microwave work has been augmented by quantum chemical calculations at the CCSD(T)/cc-pVTZ and MP2/cc-pVTZ levels of theory. Results of these calculations are generally in good agreement with experimental findings.
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Affiliation(s)
- Harald Møllendal
- Centre for Theoretical and Computational Chemistry (CTCC), Department of Chemistry, University of Oslo , Blindern, NO-0315 Oslo, Norway
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12
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Samdal S, Møllendal H, Guillemin JC. Microwave Spectrum, Conformational Composition, and Dipole Moment of (Fluoromethyl)cyclopropane (C3H5CH2F). J Phys Chem A 2014; 118:2344-52. [DOI: 10.1021/jp500985a] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Affiliation(s)
- Svein Samdal
- Centre
for Theoretical and Computational Chemistry (CTCC), Department of
Chemistry, University of Oslo, P.O. Box 1033 Blindern, NO-0315 Oslo, Norway
| | - Harald Møllendal
- Centre
for Theoretical and Computational Chemistry (CTCC), Department of
Chemistry, University of Oslo, P.O. Box 1033 Blindern, NO-0315 Oslo, Norway
| | - Jean-Claude Guillemin
- Institut des Sciences Chimiques
de Rennes, École Nationale Supérieure de Chimie de Rennes,
CNRS, UMR 6226, 11 Allée de
Beaulieu, CS 50837, 35708 Rennes Cedex 7, France
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13
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Samdal S, Grønås T, Møllendal H, Guillemin JC. Microwave Spectrum and Conformational Properties of 4-Isocyano-1-butene (H2C═CHCH2CH2N≡C). J Phys Chem A 2014; 118:1413-9. [DOI: 10.1021/jp4122134] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Affiliation(s)
- Svein Samdal
- Centre
for Theoretical and Computational Chemistry (CTCC), Department of
Chemistry, University of Oslo, P.O. Box 1033 Blindern, NO-0315 Oslo, Norway
| | - Terje Grønås
- Centre
for Theoretical and Computational Chemistry (CTCC), Department of
Chemistry, University of Oslo, P.O. Box 1033 Blindern, NO-0315 Oslo, Norway
| | - Harald Møllendal
- Centre
for Theoretical and Computational Chemistry (CTCC), Department of
Chemistry, University of Oslo, P.O. Box 1033 Blindern, NO-0315 Oslo, Norway
| | - Jean-Claude Guillemin
- Institut
des Sciences Chimiques de Rennes, École Nationale Supérieure de Chimie de Rennes, CNRS, UMR 6226, 11 Allée de Beaulieu, CS 50837, 35708 Rennes Cedex
7, France
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14
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Samdal S, Møllendal H, Guillemin JC. Microwave spectrum and conformational properties of 4-isocyano-1-butyne (HC≡CCH2CH2N≡C). J Phys Chem A 2013; 117:10304-10. [PMID: 24003874 DOI: 10.1021/jp407126x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The microwave spectrum of 4-isocyano-1-butyne (HC≡CCH2CH2N≡C) has been investigated in the 12.4-77.6 GHz spectral region. The spectra of two rotamers denoted ap and sc were assigned. ap has an antiperiplanar arrangement for the C-C-C-N chain of atoms, whereas sc has synclinal conformation for this link. The ground state spectrum and three vibrationally excited state spectra of the lowest torsional vibration were assigned for ap, while the ground vibrational state spectrum was assigned for sc. The C-C-C-N dihedral angle was found to be 64.5(30)° in sc and exactly 180° in ap. ap was determined to be 2.9(6) kJ/mol lower in energy than sc from relative intensity measurements. The microwave study has been augmented with ab initio and DFT calculations employing the CCSD(T), MP2, and B3LYP methods with the cc-pVTZ basis set. A Natural Bond Order analysis has also been performed. Most, but not all, of the quantum chemical predictions agree satisfactorily with the experimental results.
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Affiliation(s)
- Svein Samdal
- Centre for Theoretical and Computational Chemistry (CTCC), Department of Chemistry, University of Oslo , P.O. Box 1033 Blindern, NO-0315 Oslo, Norway
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15
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Craig NC, Chen Y, Fuson HA, Tian H, van Besien H, Conrad AR, Tubergen MJ, Rudolph HD, Demaison J. Microwave spectra of the deuterium isotopologues of cis-hexatriene and a semiexperimental equilibrium structure. J Phys Chem A 2013; 117:9391-400. [PMID: 23237234 DOI: 10.1021/jp311035c] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Microwave transitions and ground state rotational constants are reported for five newly synthesized deuterium isotopologues of cis-1,3,5-hexatriene (cHTE). These rotational constants along with those of the parent and the three (13)C species are used with vibration-rotation constants calculated from an MP2/cc-pVTZ model to derive an equilibrium structure. That structure is improved by the mixed estimation method. In this method, internal coordinates from good-quality quantum chemical calculations (with appropriate uncertainties) are fit simultaneously with moments of inertia of the full set of isotopologues. The new structure of cHTE is confirmed to be planar and is stabilized by an interaction between the hydrogen atoms H2 and H5, which form a bond and participate in a six-membered ring. cHTE shows larger structural effects of π-electron delocalization than does butadiene with the effects being magnified in the center of the molecule. Thus, strong structural evidence now exists for an increase in π-electron delocalization as the polyene chain lengthens.
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Affiliation(s)
- Norman C Craig
- Department of Chemistry and Biochemistry, Oberlin College , Oberlin, Ohio 44074, United States
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16
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Samdal S, Møllendal H, Guillemin JC. Microwave Spectrum, Conformational Properties, and Dipole Moment of Cyclopropylmethyl Isocyanide (C3H5CH2NC). J Phys Chem A 2013; 117:5073-81. [DOI: 10.1021/jp403374k] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Affiliation(s)
- Svein Samdal
- Centre for Theoretical and Computational
Chemistry (CTCC), Department of Chemistry, University of Oslo, P.O. Box 1033 Blindern, NO-0315 Oslo, Norway
| | - Harald Møllendal
- Centre for Theoretical and Computational
Chemistry (CTCC), Department of Chemistry, University of Oslo, P.O. Box 1033 Blindern, NO-0315 Oslo, Norway
| | - Jean-Claude Guillemin
- Institut des Sciences Chimiques
de Rennes, École Nationale Supérieure de Chimie de Rennes,
CNRS, UMR 6226, Avenue du Général
Leclerc, CS 50837, 35708 Rennes Cedex 7, France
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Samdal S, Møllendal H, Guillemin JC. Synthesis, microwave spectrum, and conformational properties of 2-fluoroethyl azide (FCH2CH2N3). J Phys Chem A 2013; 117:1935-40. [PMID: 23379369 DOI: 10.1021/jp312227t] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A novel synthesis producing neat 2-fluoroethyl azide (FCH2CH2N3) is described. A conformational analysis using microwave spectroscopy augmented by quantum chemical calculations at the CCSD(T)/cc-pVTZ, B3LYP/aug-cc-pVTZ, and B3LYP/cc-pVTZ levels of theory has been performed for this compound. The spectra of the ground vibrational state and two vibrationally excited states of one rotameric form were assigned. A large number of transitions was assigned, and very accurate values were obtained for the rotational and quartic centrifugal distortion constants. The identified conformer has synclinal orientations for the F-C-C-N and C-C-N-N chains of atoms bringing the fluorine atom and the azido group into close proximity. It is concluded from consideration of absolute intensities that this conformer is indeed the preferred form of the molecule in accord with the theoretical calculations. The experimental and CCSD(T) rotational constants are in very good agreement, whereas much larger discrepancies were seen for the experimental and B3LYP quartic centrifugal distortion constants.
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Affiliation(s)
- Svein Samdal
- Centre for Theoretical and Computational Chemistry (CTCC), Department of Chemistry, University of Oslo, P.O. Box 1033 Blindern, NO-0315 Oslo, Norway
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18
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Møllendal H, Samdal S. Microwave Spectra, Planarity, and Conformational Preferences of cis- and trans-N-Vinylformamide. J Phys Chem A 2012; 116:12073-81. [DOI: 10.1021/jp309552m] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- Harald Møllendal
- Centre for Theoretical and Computational Chemistry, Department of Chemistry, University of Oslo, P.O. Box 1033 Blindern, NO-0315 Oslo, Norway.
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19
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Craig NC, Fuson HA, Tian H, Blake TA. Analysis of the rotational structure in the high-resolution infrared spectra of trans-hexatriene-1,1-d2 and -cis-1-d1. J Mol Struct 2012. [DOI: 10.1016/j.molstruc.2012.03.044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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20
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Craig NC, Tian H, Blake TA. Analysis of the rotational structure in the high-resolution infrared spectrum of trans-hexatriene-1-13C1: a semiexperimental equilibrium structure for the C6 backbone of trans-hexatriene. J Phys Chem A 2012; 116:3148-55. [PMID: 22372943 DOI: 10.1021/jp211791r] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
trans-Hexatriene-1-(13)C(1) (tHTE-1-(13)C(1)) has been synthesized, and its high-resolution (0.0015 cm(-1)) infrared spectrum has been recorded. The rotational structure in the C-type bands for ν(26) at 1011 cm(-1) and ν(30) at 894 cm(-1) has been analyzed. To the 1458 ground state combination differences from these bands, ground state rotational constants were fitted to a Watson-type Hamiltonian to give A(0) = 0.8728202(9), B(0) = 0.0435868(4), and C(0) = 0.0415314(2) cm(-1). Upper state rotational constants for the ν(30) band were also fitted. Predictions of the ground state rotational constants for tHTE-1-(13)C(1) from a B3LYP/cc-pVTZ model with scale factors based on the normal species were in excellent agreement with observations. Similar good agreement was found between predicted and observed ground state rotational constants for the three (13)C(1) isotopologues of cis-hexatriene, as determined from microwave spectroscopy. Equilibrium rotational constants for tHTE and its three (13)C(1) isotopologues, of which two were predicted, were used to find a semiexperimental equilibrium structure for the C(6) backbone of tHTE. This structure shows increased structural effects of π-electron delocalization in comparison with butadiene and some differences from the cis isomer of HTE. Structures predicted with the MP2/cc-pVTZ model are also compared.
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Affiliation(s)
- Norman C Craig
- Department of Chemistry and Biochemistry, Oberlin College, Oberlin, Ohio 44074, USA
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21
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Law MM, Fraser-Smith JT, Perotto CU. The potential energy surface of isomerising disilyne. Phys Chem Chem Phys 2012; 14:6922-36. [DOI: 10.1039/c2cp40605e] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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22
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Charmet AP, Tasinato N, Stoppa P, Giorgianni S, Gambi A. Anharmonic resonances in the CH chromophore overtone spectra of CHBrF2. Mol Phys 2011. [DOI: 10.1080/00268976.2011.609138] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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23
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DeYonker NJ, Wilson BR, Pierpont AW, Cundari TR, Wilson AK. Towards the intrinsic error of the correlation consistent Composite Approach (ccCA). Mol Phys 2010. [DOI: 10.1080/00268970902744359] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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24
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McKean DC, Law MM, Groner P, Conrad AR, Tubergen MJ, Feller D, Moore MC, Craig NC. Infrared Spectra of CF2═CHD and CF2═CD2: Scaled Quantum-Chemical Force Fields and an Equilibrium Structure for 1,1-Difluoroethylene. J Phys Chem A 2010; 114:9309-18. [DOI: 10.1021/jp104498n] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Affiliation(s)
- Donald C. McKean
- School of Chemistry, University of Edinburgh, West Mains Road, Edinburgh EH9 3JJ, United Kingdom, Chemistry Department, University of Aberdeen, Meston Walk, Aberdeen AB24 3UE, United Kingdom, Department of Chemistry, University of Missouri—Kansas City, Kansas City, Missouri 64110-2499, Department of Chemistry, Kent State University, Kent, Ohio 44242, Department of Chemistry, Washington State University, Pullman, Washington 99164-4630, and Department of Chemistry and Biochemistry, Oberlin College, Oberlin
| | - Mark M. Law
- School of Chemistry, University of Edinburgh, West Mains Road, Edinburgh EH9 3JJ, United Kingdom, Chemistry Department, University of Aberdeen, Meston Walk, Aberdeen AB24 3UE, United Kingdom, Department of Chemistry, University of Missouri—Kansas City, Kansas City, Missouri 64110-2499, Department of Chemistry, Kent State University, Kent, Ohio 44242, Department of Chemistry, Washington State University, Pullman, Washington 99164-4630, and Department of Chemistry and Biochemistry, Oberlin College, Oberlin
| | - Peter Groner
- School of Chemistry, University of Edinburgh, West Mains Road, Edinburgh EH9 3JJ, United Kingdom, Chemistry Department, University of Aberdeen, Meston Walk, Aberdeen AB24 3UE, United Kingdom, Department of Chemistry, University of Missouri—Kansas City, Kansas City, Missouri 64110-2499, Department of Chemistry, Kent State University, Kent, Ohio 44242, Department of Chemistry, Washington State University, Pullman, Washington 99164-4630, and Department of Chemistry and Biochemistry, Oberlin College, Oberlin
| | - Andrew R. Conrad
- School of Chemistry, University of Edinburgh, West Mains Road, Edinburgh EH9 3JJ, United Kingdom, Chemistry Department, University of Aberdeen, Meston Walk, Aberdeen AB24 3UE, United Kingdom, Department of Chemistry, University of Missouri—Kansas City, Kansas City, Missouri 64110-2499, Department of Chemistry, Kent State University, Kent, Ohio 44242, Department of Chemistry, Washington State University, Pullman, Washington 99164-4630, and Department of Chemistry and Biochemistry, Oberlin College, Oberlin
| | - Michael J. Tubergen
- School of Chemistry, University of Edinburgh, West Mains Road, Edinburgh EH9 3JJ, United Kingdom, Chemistry Department, University of Aberdeen, Meston Walk, Aberdeen AB24 3UE, United Kingdom, Department of Chemistry, University of Missouri—Kansas City, Kansas City, Missouri 64110-2499, Department of Chemistry, Kent State University, Kent, Ohio 44242, Department of Chemistry, Washington State University, Pullman, Washington 99164-4630, and Department of Chemistry and Biochemistry, Oberlin College, Oberlin
| | - David Feller
- School of Chemistry, University of Edinburgh, West Mains Road, Edinburgh EH9 3JJ, United Kingdom, Chemistry Department, University of Aberdeen, Meston Walk, Aberdeen AB24 3UE, United Kingdom, Department of Chemistry, University of Missouri—Kansas City, Kansas City, Missouri 64110-2499, Department of Chemistry, Kent State University, Kent, Ohio 44242, Department of Chemistry, Washington State University, Pullman, Washington 99164-4630, and Department of Chemistry and Biochemistry, Oberlin College, Oberlin
| | - Michael C. Moore
- School of Chemistry, University of Edinburgh, West Mains Road, Edinburgh EH9 3JJ, United Kingdom, Chemistry Department, University of Aberdeen, Meston Walk, Aberdeen AB24 3UE, United Kingdom, Department of Chemistry, University of Missouri—Kansas City, Kansas City, Missouri 64110-2499, Department of Chemistry, Kent State University, Kent, Ohio 44242, Department of Chemistry, Washington State University, Pullman, Washington 99164-4630, and Department of Chemistry and Biochemistry, Oberlin College, Oberlin
| | - Norman C. Craig
- School of Chemistry, University of Edinburgh, West Mains Road, Edinburgh EH9 3JJ, United Kingdom, Chemistry Department, University of Aberdeen, Meston Walk, Aberdeen AB24 3UE, United Kingdom, Department of Chemistry, University of Missouri—Kansas City, Kansas City, Missouri 64110-2499, Department of Chemistry, Kent State University, Kent, Ohio 44242, Department of Chemistry, Washington State University, Pullman, Washington 99164-4630, and Department of Chemistry and Biochemistry, Oberlin College, Oberlin
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Das P, Manogaran S, Arunan E, Das PK. Infrared Spectra of Dimethylquinolines in the Gas Phase: Experiment and Theory. J Phys Chem A 2010; 114:8351-8. [DOI: 10.1021/jp1056896] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Prasanta Das
- Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore-560012, India and Department of Chemistry, Indian Institute of Technology, Kanpur-208016, India
| | - S. Manogaran
- Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore-560012, India and Department of Chemistry, Indian Institute of Technology, Kanpur-208016, India
| | - E. Arunan
- Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore-560012, India and Department of Chemistry, Indian Institute of Technology, Kanpur-208016, India
| | - Puspendu K. Das
- Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore-560012, India and Department of Chemistry, Indian Institute of Technology, Kanpur-208016, India
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26
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Coats AM, McKean DC, Edwards HG, Fawcett VA. Infrared and Raman spectra of trimethoxyborane isotopomers and quantum-chemical studies of structure and force field. J Mol Struct 2010. [DOI: 10.1016/j.molstruc.2010.02.073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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27
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Møllendal H, Khater B, Guillemin JC. Synthesis, microwave spectrum, and conformational equilibrium of propa-1,2-dienethiol (H(2)=C=CHSH). J Phys Chem A 2009; 113:5906-11. [PMID: 19402682 DOI: 10.1021/jp901817m] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The first synthesis of the kinetically unstable compound propa-1,2-dienethiol (allenethiol; H(2)CCCHSH) is reported. Its microwave spectrum has been studied in the 41.5-80 GHz spectral range. The spectra of two rotameric forms have been assigned. The C-C-S-H chain of atoms is synperiplanar (0 degrees ) in one of the conformers. This dihedral angle is anticlinal in the second rotamer forming an angle of 140(5) degrees in the second form. The synperiplanar conformer is found to be 1.0(6) kJ/mol more stable than the anticlinal rotamer. The microwave study has been augmented by quantum chemical calculations at the MP2/aug-cc-pVTZ and B3LYP/6-311++G** levels of theory. The predictions of these two theoretical methods are in excellent agreement with the experimental findings.
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Affiliation(s)
- Harald Møllendal
- Centre for Theoretical and Computational Chemistry (CTCC), Department of Chemistry, University of Oslo, P.O. Box 1033 Blindern, NO-0315 Oslo, Norway.
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28
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Suenram RD, Pate BH, Lesarri A, Neill JL, Shipman S, Holmes RA, Leyden MC, Craig NC. Semiexperimental equilibrium structure for the C6 backbone of cis-1,3,5-hexatriene; structural evidence for greater pi-electron delocalization with increasing chain length in polyenes. J Phys Chem A 2009; 113:1864-8. [PMID: 19196001 DOI: 10.1021/jp8106777] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Twenty-five microwave lines were observed for cis-1,3,5-hexatriene (0.05 D dipole moment) and a smaller number for its three (13)C isotopomers in natural abundance. Ground-state rotational constants were fitted for all four species to a Watson-type rotational Hamiltonian for an asymmetric top (kappa = -0.9768). Vibration-rotation (alpha) constants were predicted with a B3LYP/cc-pVTZ model and used to adjust the ground-state rotational constants to equilibrium rotational constants. The small inertial defect for cis-hexatriene shows that the molecule is planar, despite significant H-H repulsion. The substitution method was applied to the equilibrium rotational constants to give a semiexperimental equilibrium structure for the C(6) backbone. This structure and one predicted with the B3LYP/cc-pVTZ model show structural evidence for increased pi-electron delocalization in comparison with butadiene, the first member of the polyene series.
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Affiliation(s)
- Richard D Suenram
- Department of Chemistry, University of Virginia, Charlottesville, Virginia 22904, USA
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29
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McKean DC, Craig NC, Law MM. Vibrational Anharmonicity and Harmonic Force Fields for Dichloromethane from Quantum-Chemical Calculations. J Phys Chem A 2008; 112:10006-16. [DOI: 10.1021/jp803881c] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- Donald C. McKean
- School of Chemistry, University of Edinburgh, West Mains Road, Edinburgh EH9 3JJ, U.K., Department of Chemistry and Biochemistry, Oberlin College, Oberlin, Ohio 44074, and Chemistry Department, University of Aberdeen, Meston Walk, Aberdeen AB24 3UE, U.K
| | - Norman C. Craig
- School of Chemistry, University of Edinburgh, West Mains Road, Edinburgh EH9 3JJ, U.K., Department of Chemistry and Biochemistry, Oberlin College, Oberlin, Ohio 44074, and Chemistry Department, University of Aberdeen, Meston Walk, Aberdeen AB24 3UE, U.K
| | - Mark M. Law
- School of Chemistry, University of Edinburgh, West Mains Road, Edinburgh EH9 3JJ, U.K., Department of Chemistry and Biochemistry, Oberlin College, Oberlin, Ohio 44074, and Chemistry Department, University of Aberdeen, Meston Walk, Aberdeen AB24 3UE, U.K
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