Microwave Spectrum and Intramolecular Hydrogen Bonding of 2-Isocyanoethanol (HOCH<sub>2</sub>CH<sub>2</sub>N≡C)

Møllendal, Harald; Samdal, Svein; Guillemin, Jean‐Claude

doi:10.1021/jp502212n

Cited by 4 publications

(6 citation statements)

References 63 publications

(104 reference statements)

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“…Under these conditions, the vibrational spectrum becomes simpler and different conformers can be more easily identified and characterized. Microwave spectra were recorded at room temperature or somewhat below [ 24 , 25 , 26 , 27 ]. Gas-phase electron diffraction structure determinations, sometimes at two or three different temperatures, were performed in the range of 297–733 K [ 28 , 29 , 30 , 31 ].…”

Section: Methodsmentioning

confidence: 99%

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Competing Intramolecular vs. Intermolecular Hydrogen Bonds in Solution

Nagy

2014

IJMS

151

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A hydrogen bond for a local-minimum-energy structure can be identified according to the definition of the International Union of Pure and Applied Chemistry (IUPAC recommendation 2011) or by finding a special bond critical point on the density map of the structure in the framework of the atoms-in-molecules theory. Nonetheless, a given structural conformation may be simply favored by electrostatic interactions. The present review surveys the in-solution competition of the conformations with intramolecular vs. intermolecular hydrogen bonds for different types of small organic molecules. In their most stable gas-phase structure, an intramolecular hydrogen bond is possible. In a protic solution, the intramolecular hydrogen bond may disrupt in favor of two solute-solvent intermolecular hydrogen bonds. The balance of the increased internal energy and the stabilizing effect of the solute-solvent interactions regulates the new conformer composition in the liquid phase. The review additionally considers the solvent effects on the stability of simple dimeric systems as revealed from molecular dynamics simulations or on the basis of the calculated potential of mean force curves. Finally, studies of the solvent effects on the type of the intermolecular hydrogen bond (neutral or ionic) in acid-base complexes have been surveyed.

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Section: Methodsmentioning

confidence: 99%

“…2-NC ethanol (2-isocyanoethanol). Only gas-phase studies have been found for the molecule by Møllendal et al [ 26 ]. Out of five considered conformers, the OCCN gauche structure is the most stable with an (O)H…N distance of 256 pm.…”

Section: Conformational Equilibriamentioning

confidence: 99%

Competing Intramolecular vs. Intermolecular Hydrogen Bonds in Solution

Nagy

2014

IJMS

151

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“…Much of our work has focused on weak proton donor groups. Recently, we reported gas-phase studies of alcohols, − carboxylic acids, thiols, − thiolcarboxylic acids, selenols, − amines, − amides, , and phosphines, − where the said groups are proton donors in internal H bonds with acceptors such as the fluorine atom, ,,, the chlorine atom, ,,, π-electrons of triple bonds, − ,,,, π-electrons of double bonds, ,,,, and Walsh pseudo-π electrons. ,, References of many of our earlier works are found in the cited literature as well as in reviews. − …”

Section: Introductionmentioning

confidence: 99%

Microwave and Quantum Chemical Study of the Hydrazino Group as Proton Donor in Intramolecular Hydrogen Bonding of (2-Fluoroethyl)hydrazine (FCH₂CH₂NHNH₂)

2015

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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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“…Intramolecular hydrogen bonding has for a long time been a favorite research theme of the Oslo laboratory, and a number of hydrogen bonds with a wide variety of hydrogen donors and acceptors have been investigated over the years. In the past several years, we have reported microwave (MW) spectra of the following molecules having internal hydrogen bonds: 2-isocyanoethanol (HOCH 2 CH 2 NC), 2-aminopropionitrile (H 2 NCH(CH 3 )CN), (2-chloroethyl)amine (ClCH 2 CH 2 NH 2 ), (chloromethyl)phosphine (ClCH 2 PH 2 ), propargylselenol (HCCCH 2 SeH), 2-propene-1-selenol (H 2 CCHCH 2 SeH), 2,2,2-trifluoroethanethiol (CF 3 CH 2 SH), 3-butyne-1-selenol (HSeCH 2 CH 2 CCH), 4-pentyn-1-ol (HOCH 2 CH 2 CH 2 CCH), ( Z )-3-mercapto-2-propenenitrile (HSCHCHCN), ( Z )-3-amino-2-propenenitrile (H 2 NCHCHCN), 3-butyne-1-thiol (HSCH 2 CH 2 CCH), (methylenecyclopropyl)methanol (H 2 CC 3 H 3 CH 2 OH), 2-chloroacetamide (ClCH 2 CONH 2 ), and cyclopropylmethylselenol (C 3 H 5 CH 2 SeH) . References to earlier work by us and others are found in these papers as well as in several reviews. − …”

Section: Introductionmentioning

confidence: 99%

“…1 H NMR (CDCl 3 , 400 MHz) δ 2.80 (d, 1H, 4 J HH = 2.6 Hz, CCH), 4.27 (d, 1H, 3 J HH = 6.8 Hz, OH), 5.23 (dd, 1H,3 J HH = 6.8 Hz,4 J HH = 2.6 Hz, CHO) 13. C NMR (CDCl 3 , 100 MHz) δ 50.7 ( 1 J CH = 157.5 Hz (d), OCH), 75.3 ( 2 J CH = 51.3 Hz (d), CCH), 76.8 ( 1 J CH = 257.5 Hz (d), CCH), 115.8 (CN).…”

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confidence: 99%

Microwave and Quantum-Chemical Study of Conformational Properties and Intramolecular Hydrogen Bonding of 2-Hydroxy-3-Butynenitrile (HC≡CCH(OH)C≡N)

2015

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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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Microwave Spectrum and Intramolecular Hydrogen Bonding of 2-Isocyanoethanol (HOCH₂CH₂N≡C)

Cited by 4 publications

References 63 publications

Competing Intramolecular vs. Intermolecular Hydrogen Bonds in Solution

Competing Intramolecular vs. Intermolecular Hydrogen Bonds in Solution

Microwave and Quantum Chemical Study of the Hydrazino Group as Proton Donor in Intramolecular Hydrogen Bonding of (2-Fluoroethyl)hydrazine (FCH₂CH₂NHNH₂)

Microwave and Quantum-Chemical Study of Conformational Properties and Intramolecular Hydrogen Bonding of 2-Hydroxy-3-Butynenitrile (HC≡CCH(OH)C≡N)

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Microwave Spectrum and Intramolecular Hydrogen Bonding of 2-Isocyanoethanol (HOCH2CH2N≡C)

Cited by 4 publications

References 63 publications

Competing Intramolecular vs. Intermolecular Hydrogen Bonds in Solution

Competing Intramolecular vs. Intermolecular Hydrogen Bonds in Solution

Microwave and Quantum Chemical Study of the Hydrazino Group as Proton Donor in Intramolecular Hydrogen Bonding of (2-Fluoroethyl)hydrazine (FCH2CH2NHNH2)

Microwave and Quantum-Chemical Study of Conformational Properties and Intramolecular Hydrogen Bonding of 2-Hydroxy-3-Butynenitrile (HC≡CCH(OH)C≡N)

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Microwave Spectrum and Intramolecular Hydrogen Bonding of 2-Isocyanoethanol (HOCH₂CH₂N≡C)

Microwave and Quantum Chemical Study of the Hydrazino Group as Proton Donor in Intramolecular Hydrogen Bonding of (2-Fluoroethyl)hydrazine (FCH₂CH₂NHNH₂)