A (1) (TS) J F,H(O) coupling pathway, dictated by a hydrogen bond, in some 2-fluorobenzoic acids has been observed, while such an interaction does not occur in 2-fluorophenol. Thus, this work reports the conformational analysis of 2-fluorophenylboronic acid (1), in order to evaluate a possible intramolecular OH∙∙∙F hydrogen bond in comparison to an nF→pB interaction, which mimics the quantum nF...

FTIR spectroscopic study of hydrogen bonding of 1,2-dihydroxybenzene (catechol) with proton acceptors has been carried out. The influence of intramolecular and intermolecular hydrogen bonds on the strengths of each other in complexes of 1,2-dihydroxybenzene with various proton acceptors has been analyzed. It was shown that intramolecular hydrogen bond is strengthened when 1,2-dihydroxybenzene i...

The cysteine anion was produced in the gas phase by electrospray ionization and investigated by photoelectron spectroscopy at low temperature (70 K). The cysteine anion was found to exhibit the thiolate form [-SCH2CH(NH2)CO2H], rather than the expected carboxylate form [HSCH2CH(NH2)CO2-]. This observation was confirmed by two control experiments, that is, methyl cysteine [CH3SCH2CH(NH2)CO2-] an...

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 electrostati...

An organocatalytic strategy for the synthesis of tetrasubstituted pyrrolidines with monoactivated azomethine ylides in high enantiomeric excess and excellent exo/endo selectivity is presented. The key to success is the intramolecular activation via hydrogen bonding through an o-hydroxy group, which allows the dipolar cycloaddition to take place in the presence of azomethine ylides bearing only ...

In the title compound, C(15)H(15)N(3)OS, the thio-urea group is stabilized by an intra-molecular hydrogen bond between the carbonyl O atom and the thio-amide group. A C-H⋯N intramolecular hydrogen bond is also present. Mol-ecules are linked by inter-molecular N-H⋯O and C-H⋯S hydrogen bonds.

The strength of the low-barrier hydrogen bond in hydrogen maleate in the gas phase was investigated by low-temperature photoelectron spectroscopy and ab initio calculations. Photoelectron spectra of maleic and fumaric acid monoanions (cis-/trans-HO(2)CCH=CHCO(2)(-)) were obtained at low temperatures and at 193 nm photon energy. Vibrational structure was observed for trans-HO(2)CCH=CHCO(2)(-) du...

A series of conformationally restricted triol and tetrol systems containing intramolecular hydrogen bond arrays has been prepared and characterized by X-ray crystallography and NMR spectroscopy. NMR isotopic perturbation measurements in DMSO-d6 and CD2Cl2 reveal that this methodology can be used to detect the spatial proximity of up to four contiguous hydroxyl groups sharing a 1,3-, 1,4-, or 1,...

The Gibbs free energy, enthalpy and entropy of partitioning of 45 simple aromatic compounds (phenols, benzoic acids and acetanilides) from water to octanol and from water to cyclohexane have been determined using the filter-probe method. This involved the measurement of partition coefficients over the temperature range 20-45C. The aim of the work was to explore the effects of intramolecular hyd...