A Low Temperature Infrared Study of Hydrogen Bonding in N-Alkylacetamides

1973 ◽  
Vol 51 (21) ◽  
pp. 3640-3646 ◽  
Author(s):  
Marie-Claude Bernard-Houplain ◽  
C. Sandorfy
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Low Temperature ◽  
Infrared Spectra ◽  
Bond Formation ◽  
Coupling Constant ◽  
Infrared Study ◽  
Hydrogen Bond Formation ◽  
Stretching Vibration ◽  
Secondary Amides

The infrared spectra of N-methylacetamide and two other secondary amides were measured in solution at temperatures ranging from 22 to −190 °C in both the fundamental and the overtone regions. At least two hydrogen bonded species are found as association increases with decreasing temperature. The effect of hydrogen bond formation on the anharmonicity of the NH stretching vibration and on the NH stretching – NH bending coupling constant is examined.

Anharmonicity, solvent effects, and hydrogen bonding: NH stretching vibrations

1970 ◽  
Vol 48 (14) ◽  
pp. 2197-2203 ◽  
Author(s):  
A. Foldes ◽  
C. Sandorfy
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Solvent Effects ◽  
Bond Formation ◽  
Hydrogen Bond Formation ◽  
Stretching Vibration ◽  
Solvent Shifts ◽  
Stretching Vibrations ◽  
Secondary Amides ◽  
Influence Of Solvent

The influence of solvent effects and hydrogen bond formation on the anharmonicity of the NH stretching vibration of simple secondary amides, lactams, anilides, indole, pyrrole, and imidazole have been studied; and the frequencies of the first and second overtones, their half widths and solvent shifts measured. The validity of Buckingham's theory is established in the case of inert solvents; whereas the second order perturbation treatments are shown to be inapplicable to the case of hydrogen bonding solvents. All NH stretching modes seem to exhibit the same anharmonic behavior which is very different from that of OH vibrations.

A Low Temperature Infrared Study of Self-association in Thiols

1972 ◽  
Vol 50 (22) ◽  
pp. 3594-3600 ◽  
Author(s):  
R. Bicca de Alencastro ◽  
C. Sandorfy
Keyword(s):  
Hydrogen Bonding ◽  
Low Temperature ◽  
Infrared Spectra ◽  
Low Temperatures ◽  
Infrared Study ◽  
Text Type ◽  
Stretching Vibration ◽  
Aliphatic Thiols ◽  
Self Association ◽  
Associated Species

The infrared spectra of several aliphatic thiols and of benzenethiol were measured between 2400 and 2700 cm−1, and 4800 and 5300 cm−1 in a 1:1 mixture of CCl3F and C2F4Br2, at temperatures ranging from 20 to −190 °C. Dimerization takes place at low temperatures and more highly associated species also appear. Free S—H groups are present in the solutions as well as in the pure liquids, even at the lowest temperatures. The association is of the [Formula: see text] type in aliphatic thiols; both [Formula: see text] and [Formula: see text] bonds are found in the case of benzenethiol and α-toluenethiol. Hydrogen bonding has little effect on the anharmonicity of the S—H stretching vibration.

A Low Temperature Infrared Study on the Association of Thiols with Pyridine and Triethylamine

1973 ◽  
Vol 51 (7) ◽  
pp. 985-990 ◽  
Author(s):  
R. Bicca De Alencastro ◽  
C. Sandorfy
Keyword(s):  
Low Temperatures ◽  
Bond Formation ◽  
Infrared Study ◽  
Hydrogen Bond Formation ◽  
Text Type ◽  
Predominant Species ◽  
Type Complex ◽  
Proton Donors ◽  
Stretching Vibration ◽  
Associated Species

The infrared spectra of solutions containing propane-1-thiol or benzenethiol as proton donors, and pyridine or triethylamine as proton acceptors were measured down to about −100 °C. The dependence of hydrogen bond formation on concentration and temperature was studied at the fundamental and overtone region of the S—H stretching vibration. The predominant species is found to be a 1:1 [Formula: see text] type complex. In addition, evidence was found for the existence of more highly associated species at low temperatures. Thiol–thiol [Formula: see text] type hydrogen bonds are also present in the case of benzenethiol–pyridine mixtures.

Enthalpies of hydrogen bond formation of 1-octanol with aprotic organic solvents. A comparison of the solvation enthalpy, pure base, and non-hydrogen-bonding baseline methods

1985 ◽  
Vol 63 (2) ◽  
pp. 342-348 ◽  
Author(s):  
W. Kirk Stephenson ◽  
Richard Fuchs
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Bond Formation ◽  
Enthalpies Of Solution ◽  
Dispersion Interactions ◽  
Butyl Ether ◽  
Hydrogen Bond Formation ◽  
Solvation Enthalpy ◽  
Benzene Toluene ◽  
Good Agreement

Enthalpies of solution (ΔHs) of 1-octanol and five model compounds (di-n-butyl ether, n-heptyl methyl ether, 1-fluoro-octane, 1-chlorooctane, and n-octane) have been determined in 13 solvents (heptane, cyclohexane, CCl4, 1,1,1-trichloro-ethane, 1,2-dichloroethane, triethylamine, butyl ether, ethyl acetate, DMF, DMSO, benzene, toluene, mesitylene), and combined with heats of vaporization to give enthalpies of transfer from vapor to solvent (ΔH(v → S)). These values have been used to calculate the enthalpy of hydrogen bond formation (ΔHh) of 1-octanol with each solvent, using the pure base (PB), solvation enthalpy (SE), and non-hydrogen-bonding baseline (NHBB) methods. Evidence is presented suggesting that (a) the SE method is susceptible to mismatches of the 1-octanol vs. model polar and dispersion interactions, (b) the PB method is sensitive to polar interaction mismatches, whereas (c) the NHBB method compensates for both polar and dispersion interactions mismatches. The (apparent) ΔHh values determined by the SE and PB methods may be as much as several kcal/mol (nearly 50%) too large, because of the inclusion of other polar and dispersion interactions. The NHBB method is therefore preferred for determining enthalpies of H-bond formation from calorimetric data. However, apparent ΔHh values from the SE and PB methods can be incorporated into total solvatochromic equations using Taft–Kamiet π*, β, and ξ parameters, to provide enthalpies of H-bond formation in good agreement with ΔHh (NHBB).

Hydrogen bonding of n-alcohols of different chain lengths

1985 ◽  
Vol 63 (1) ◽  
pp. 40-45 ◽  
Author(s):  
Lucie Wilson ◽  
R. Bicca de Alencastro ◽  
C. Sandorfy
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Chain Length ◽  
Bond Formation ◽  
Hydrocarbon Chain ◽  
Hydrogen Bond Formation ◽  
Degree Of Association ◽  
Chain Lengths ◽  
Anesthetic Potency

The anesthetic potency of n-alcohols exhibits a somewhat irregular dependence on the length of the hydrocarbon chain. An attempt has therefore been made to ascertain if this is related to the relative tendency for hydrogen bond formation by these alcohols. No such relationship was found. The result was rather that the degree of association by hydrogen bond formation of dissolved alcohols appears to be independent of the chain length, that is of the extent of other interactions that exist in these solutions.

Low Temperature Infrared Study of Hydrogen Bonding in Dissolved Pyrrole and Indole

1973 ◽  
Vol 51 (7) ◽  
pp. 1075-1082 ◽  
Author(s):  
Marie-Claude Bernard-Houplain ◽  
C. Sandorfy
Keyword(s):  
Hydrogen Bonding ◽  
Low Temperature ◽  
Spectroscopic Methods ◽  
Infrared Study ◽  
Stretching Vibration ◽  
Self Association ◽  
Associated Species

Self-association by hydrogen bonding in the case ot pyrrole was studied by i.r. spectroscopic methods. The fundamental first and second overtones of the NH stretching vibration were measured at different concentrations and at temperatures ranging from 22 to −190 °C. The existence of at least two associated species in solution has been ascertained. 2,5-Dimethylpyrrole and indole were also studied and gave similar results.

scholarly journals Structures of the monofluoro- and monochlorophenols at low temperature and high pressure

2005 ◽  
Vol 61 (1) ◽  
pp. 69-79 ◽  
Author(s):  
Iain D. H. Oswald ◽  
David R. Allan ◽  
W. D. Samuel Motherwell ◽  
Simon Parsons
Keyword(s):  
Hydrogen Bond ◽  
High Pressure ◽  
Low Temperature ◽  
Ambient Pressure ◽  
Bond Formation ◽  
Screw Axis ◽  
Hydrogen Bond Formation ◽  
Independent Molecules ◽  
Two Phases ◽  
Crystallization From The Melt

2-Fluorophenol, 3-fluorophenol and 3-chlorophenol were recrystallized from frozen solids at 260, 263 and 283 K. All compounds were also crystallized by the application of high pressure (0.36, 0.12 and 0.10 GPa). While 3-fluorophenol and 3-chlorophenol yielded the same phases under both conditions, different polymorphs were obtained for 2-fluorophenol. 4-Chlorophenol was crystallized both from the melt and from benzene to yield two different ambient-pressure polymorphs; crystallization from the melt at 0.02 GPa yielded the same phase as from benzene at ambient pressure. 3-Fluorophenol is unusual in forming a hydrogen-bonded chain along a 21 screw axis. Such behaviour is usually only observed for small alcohols, but here it appears to be stabilized by intermolecular C—H...F hydrogen-bond formation. 3-Chlorophenol is a more typical large alcohol and emulates a fourfold screw axis with two independent molecules positioned about a 21 axis, although there are significant distortions from this ideal geometry. The two phases of 4-chlorophenol consist of chains or rings connected by C—Cl...H interactions. The low-temperature and high-pressure polymorphs of 2-fluorophenol consist of chains of molecules connected through OH...OH hydrogen bonds; while inter-chain C—H...F interactions are significant at high pressure, there are none in the low-temperature form.

A nuclear magnetic resonance study of hydrogen bonding of δ-valerolactam

1969 ◽  
Vol 47 (19) ◽  
pp. 3655-3660 ◽  
Author(s):  
J. M. Purcell ◽  
H. Susi ◽  
J. R. Cavanaugh
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Magnetic Resonance ◽  
Chemical Shifts ◽  
Bond Formation ◽  
Resonance Spectroscopy ◽  
Hydrogen Bond Formation ◽  
Wide Range ◽  
Nuclear Magnetic

The association of amide groups of δ-valerolactam through hydrogen bonding has been investigated by means of high resolution nuclear magnetic resonance spectroscopy in CCl4 and CDCl3 solutions. Chemical shifts of the NH proton signal were measured over a wide range of temperatures and concentrations. Thermodynamic properties associated with the [Formula: see text] hydrogen bond formation were evaluated from a least squares analysis by a direct search procedure with a digital computer. The obtained enthalpy values for hydrogen bond formation are in general agreement with results obtained by other methods.

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