Hydrogen-Bonding Cooperativity and Competing Inter- and Intramolecular Associations: A Unified Approach
نویسندگان
چکیده
Cooperativity in hydrogen bonding has been repeatedly invoked in the literature. Very often a distinction is made between the association constant for the “dimer” formation and the corresponding constant for the formation of association complexes beyond dimer. This work examines this cooperativity hypothesis and proposes a straightforward manner of integrating it in the framework of the lattice-fluid hydrogen-bonding (LFHB) equation-of-state model. This integration is done without altering the basic rationale of the LFHB model for the enumeration of hydrogen bond configurations for the self-association and cross-association in the system. The model can accommodate hydrogen bond cooperativity in complex systems, even polymer mixtures forming three-dimensional networks of hydrogen bonds, and permits its study over an extended range of temperatures and pressures. As additional examples of the applicability of the method, the formation of cyclic associates and of intramolecular hydrogen bonds is also examined.
منابع مشابه
FTIR study of H-bonds cooperativity in complexes of 1,2-dihydroxybenzene with proton acceptors in aprotic solvents: influence of the intramolecular hydrogen bond.
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...
متن کاملIsomerism and Hydrogen Bonding in the Cis-enol Forms of 1-(n-pyridyl)butane-1,3-diones: A Theoretical Study
Molecular structure, isomerism, conformational stability and intramolecular hydrogen bonding (IHB) of cis-enol forms of 1-(n-pyridyl)butane-1,3-diones (nPBD) (n = 2, 3, or 4) have been investigated by means of density functional theory (DFT) calculations. Energy differences for all possible nPBD cis-enol forms of isomers with respect to the most stable form of the correspondin...
متن کاملComputational study of the intramolecular proton transfer between 6-hydroxypicolinic acid tautomeric forms and intermolecular hydrogen bonding in their dimers
This paper is a density functional theory (DFT) calculation of intramolecular proton transfer (IPT) in 6-hydroxypicolinic acid (6HPA, 6-hydroxypyridine-2-carboxylic acid) tautomeric forms. The transition state for the enol-to-keto transition is reported in the gas phase and in four different solvents. The planar and non-planar dimer forms of 6HPA keto and enol, respectively, were also studied i...
متن کاملEnergetics and cooperativity in three-center hydrogen bonding interactions. II. Intramolecular hydrogen bonding systems
متن کامل
Conventional and Unconventional Intramolecular Hydrogen Bonding in some Beta-diketones
This study presents our view of unconventional and conventional intramolecular hydrogen bonds (HBs) for some beta-diketones theoretically and experimentally. According to our results, the groups such as Phenyl and t-But in beta positions increase and CF3 group decrease IHB strength, respectively. For better understanding of the substitution effects, the compounds with similar and different subs...
متن کامل