Fermi resonance and conformation in glycolaldehyde particles

2004 ◽  
Vol 82 (6) ◽  
pp. 915-924 ◽  
Author(s):  
Martin Jetzki ◽  
David Luckhaus ◽  
Ruth Signorell
Keyword(s):  
Hydrogen Bond ◽  
Fourier Transform ◽  
Gas Phase ◽  
Fermi Resonance ◽  
Dihedral Angles ◽  
Intermolecular Hydrogen Bonds ◽  
Resonance Analysis ◽  
Solid Bulk ◽  
Intramolecular Hydrogen ◽  
Good Agreement

The infrared spectra of gas-phase glycolaldehyde and small glycolaldehyde particles both exhibit a split carbonyl band around 1730 cm–1. Ab initio calculations show that this splitting can be traced back to a Fermi resonance involving the C=O-stretching band and the first overtone of the C–C-stretching band. The analysis of this resonance leads to detailed information about the conformation of glycolaldehyde in the particles. The results can be summarized as follows. (i) In the particles, monomers with OCCO dihedral angles of 0° and CCOH dihedral angles around 50° are strongly preferred. (ii) The intramolecular hydrogen bond observed in the gas phase is partly replaced by intermolecular hydrogen bonds. (iii) The calculated infrared spectrum and the results from the Fermi resonance analysis are in good agreement with the formation of long chains of monomeric glycolaldehyde. This is in contrast to the solid bulk, which consists of chemically bound dimers. Key words: Fermi resonance, conformation, glycolaldehyde particles, hydroxyacetone particles, Fourier transform infrared spectroscopy.

Energetics of Intra- and Inter-molecular Bonds in the Three Nitrophenols

1994 ◽  
Vol 47 (9) ◽  
pp. 1651 ◽  
Author(s):  
R Sabbah ◽  
M Gouali
Keyword(s):  
Thermal Analysis ◽  
Hydrogen Bond ◽  
Heat Capacity ◽  
Differential Thermal Analysis ◽  
Relative Stability ◽  
Intermolecular Bond ◽  
Resonance Energies ◽  
Heat Capacity Measurements ◽  
Intramolecular Hydrogen ◽  
Good Agreement

A thermodynamic study of the three nitrophenol isomers (general formula C6H5NO3) was realized by combustion calorimetry of small amounts of substance (a few milligrams), sublimation calorimetry, differential thermal analysis and heat capacity measurements. The experimental enthalpies of combustion, sublimation and fusion of these compounds are as follows: ortho para -ΔcH�m(s,298.15K)/kJ mol-1 2871.0�1.3 2875.1�0.9 2868.5�1.0 ΔsubH�m(298.15K)/kJ mol-1 72.30�0.28 91.23�0.49 92.39�0.43 ΔfusHm/kJ mol-1 18.32�0.35 20.54�0.34 17.33�0.10 Ttriple point/K 318.40�0.01 370.51�0.01 387.26�0.05   The strength of the intramolecular hydrogen bond in the ortho isomer was estimated equal to 20.09 kJ mol-1. The relative stability of the three isomers is discussed, and the intermolecular bond enthalpies have been determined. The experimental resonance energies Eexp,conj are 168.7, 142.8 and 148.2 kJ mol-1 for ortho -, meta- and para-nitrophenol respectively, and are in good agreement with theoretical values. The experimental atomization enthalpies Δa,expH°m(298.15K) are 6742.5�1.9, 6719.5�1.7 and 6724.9�1.8 kJ mol-1 for ortho -, meta- and para-nitrophenol respectively.

scholarly journals HIGH-RESOLUTION GAS PHASE THz SPECTROSCOPY OF THE CATECHOL LOW FREQUENCY MODES INVOLVING AN INTRAMOLECULAR HYDROGEN BOND

2021 ◽  
Author(s):  
Jonas Bruckhuisen ◽  
Arnaud Cuisset ◽  
Marie-Aline Martin-Drumel ◽  
Manuel Goubet ◽  
Thi Tran ◽  
...  
Keyword(s):  
Hydrogen Bond ◽  
High Resolution ◽  
Gas Phase ◽  
Intramolecular Hydrogen Bond ◽  
Low Frequency ◽  
Thz Spectroscopy ◽  
Intramolecular Hydrogen

scholarly journals N-[2-(Methylsulfanyl)phenyl]-2-sulfanylbenzamide

2012 ◽  
Vol 68 (8) ◽  
pp. o2400-o2400
Author(s):  
Chang-Chih Hsieh ◽  
Hon Man Lee ◽  
Yih-Chern Horng
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonds ◽  
Intramolecular Hydrogen Bond ◽  
Title Compound ◽  
Aromatic Rings ◽  
Intermolecular Hydrogen Bonds ◽  
Methyl Group ◽  
Interplanar Angle ◽  
Compound C ◽  
Intramolecular Hydrogen

In the title compound, C14H13NOS2, the S atom with the methyl group is involved in an intramolecular hydrogen bond with the amido H atom. In the crystal, the sulfanyl H atoms form intermolecular hydrogen bonds with the O atoms, connecting the molecules into zigzag chains along thecaxis. The two aromatic rings exhibit a small interplanar angle of 16.03 (9)°.

Torsional isomers in methylated aminoethanols - A jet-FT-IR study

2004 ◽  
Vol 82 (6) ◽  
pp. 1006-1012 ◽  
Author(s):  
Yaqian Liu ◽  
Corey A Rice ◽  
Martin A Suhm
Keyword(s):  
Hydrogen Bond ◽  
Gas Phase ◽  
Quantum Chemical ◽  
Supersonic Jet ◽  
Energy Difference ◽  
Ft Ir ◽  
Ir Study ◽  
Intramolecular Hydrogen ◽  
Quantum Chemical Data ◽  
Torsional Isomers

Jet-FT-IR spectra of aminoethanol (AE), N-methylaminoethanol (MAE), and N,N-dimethylaminoethanol (DMAE) are presented and compared to gas-phase and matrix isolation IR, microwave, and quantum chemical data. The intramolecular O-H···N hydrogen bond gives rise to characteristically shifted O-H stretching bands and torsional difference bands in the monomer spectra. It stabilizes one out of 14 diastereomeric monomer conformations of AE and DMAE and two out of 27 diastereomeric MAE conformations. The latter two correspond to torsional or N-inversional isomers, the interconversion of which is hindered by the intramolecular hydrogen bond. Their energy difference is found to be <1.2 kJ/mol. The intermolecular aggregation patterns of the three aminoethanols are quite distinct and non-monotonic, as suggested by their O-H stretching fingerprints.Key words: aminoethanol, IR spectroscopy, conformation, hydrogen bond, supersonic jet.

Ethyl 1-[5-amino-1-tert-butyl-3-(methylsulfanyl)-1H-pyrazole-4-carbonyl]-5-methyl-3-(methylsulfanyl)-1H-pyrazole-4-carboxylate

2006 ◽  
Vol 62 (5) ◽  
pp. o1679-o1681
Author(s):  
Jun-Fei Li ◽  
Hai-Bin Song ◽  
You-Quan Zhu ◽  
Hua-Zheng Yang
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bond ◽  
Hydrogen Bonds ◽  
Intramolecular Hydrogen Bond ◽  
Membered Ring ◽  
Intermolecular Hydrogen Bonds ◽  
Tert Butyl ◽  
The Family ◽  
Title Molecule ◽  
Intramolecular Hydrogen

The title molecule, C17H25N5O3S2, belongs to the family of bis-heterocycles. In the crystal structure, there are one intra- and two intermolecular hydrogen bonds. One of the two pyrazole rings and the six-membered ring formed by the intramolecular hydrogen bond are approximately coplanar.

Effect of Intramolecular Hydrogen Bonds on the Gas-Phase Basicity of Guanidines

2014 ◽  
Vol 67 (7) ◽  
pp. 1056 ◽  
Author(s):  
Zoran Glasovac ◽  
Mirjana Eckert-Maksić
Keyword(s):  
Hydrogen Bond ◽  
Gas Phase ◽  
Model Systems ◽  
Chain Model ◽  
Open Chain ◽  
Independent Variables ◽  
Wide Range ◽  
Intramolecular Hydrogen ◽  
Gas Phase Basicities ◽  
Two Independent Variables

Three series of novel trisubstituted guanidines containing at least one hydrogen bond accepting (HBA) group were modelled using B3LYP/6–311+G(2df,p)//B3LYP/6–31G(d) calculations. Their structure was modified by incorporating a variety of different HBA groups covering a wide range of hydrogen bond strengths. Calculated gas-phase basicities (GBs) ranged from 1035 to 1181 kJ mol–1 depending on the nature of the substituent. To rationalise changes in the GB, a correlation of GB against two independent variables (pKHB and σ4B) was conducted where pKHB served as the descriptor of the hydrogen bond strength and σ4B was introduced to describe changes in the GBs in the open-chain model systems, i.e. in the absence of intramolecular hydrogen bond (IMHB), caused by the electronic effect of the propyl-HBA substituent. A very good correlation of the calculated gas-phase basicities against these two independent variables was established for all three sets of the bases.

scholarly journals (3-Ammonio-2,2-dimethyl-propyl)carbamate Dihydrate

Molbank ◽  
10.3390/m1015 ◽  
2018 ◽  
Vol 2018 (3) ◽  
pp. M1015
Author(s):  
Jaqueline Heimgert ◽  
Dennis Neumann ◽  
Guido Reiss
Keyword(s):  
Hydrogen Bond ◽  
Raman Spectroscopy ◽  
Acetic Acid ◽  
Hydrogen Bonds ◽  
Chain Structure ◽  
X Ray Diffraction ◽  
Intermolecular Hydrogen Bonds ◽  
X Ray ◽  
Title Molecule ◽  
Intramolecular Hydrogen

(3-Ammonio-2,2-dimethylpropyl)carbamate dihydrate was synthesised. The title compound was characterised by single crystal X-ray diffraction and IR-/Raman-spectroscopy. It has been demonstrated that a mixture of dilute acetic acid and 2,2-dimethyl-1,3-diaminopropane is able to capture CO2 spontaneously from the atmosphere. An intramolecular hydrogen bond stabilises the conformation of the ylide-type title molecule. Intermolecular hydrogen bonds between all moieties connect them to a strand-type chain structure.

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