Chemistry hydrogen bonds

Chemical compounds that contain methylol groups (-CH2 OH) form stable, covalent bonds with cellulose fibers. Those compounds are well known and widely used in textile chemistry. Hydrogen bonds with cellulose can be formed in this reaction as well. The treatment of cellulose with methylolmelamine compounds before forming cellulose unsaturated polyesters (UP) composites decreases the moisture pickup and increases the wet strength of reinforced plastic [48,49]. 

Quantum Chem. Symp., 18, 601 (1984). Parallelism in Quantum Chemistry Hydrogen Bond Study in DNA Base Pairs as an Example. 

Wilcox. C.S. Adrian. J.C. Webb. T.H. Zawacki. F.J. Chemistry of synthetic receptors and functional group arrays. 18. Approaches to quantitative supramolecular chemistry. Hydrogen-bond-based molecular recognition phenomena and sigmoidal behavior in multicomponent mixtures. J. Am. Chem. Soc. 1992. 114. 10189-10197. 

Gerber R B, McCoy A B and Garcia-Vela A 1995 Dynamics of photoinduced reactions in the van der Waals and in the hydrogen-bonded clusters Femtosecond Chemistry Proc. Berlin Conf. Femtosecond Chemistry (Berlin, March 1993) ed J Manz and L Woeste (Weinheim Verlag Chemie) pp 499-531... 

Dyke T R 1984 Microwave and radiofrequency spectra of hydrogen-bonded complexes in the vapor phase Topics in Current Chemistry 120 85-113... 

DFT calculations offer a good compromise between speed and accuracy. They are well suited for problem molecules such as transition metal complexes. This feature has revolutionized computational inorganic chemistry. DFT often underestimates activation energies and many functionals reproduce hydrogen bonds poorly. Weak van der Waals interactions (dispersion) are not reproduced by DFT a weakness that is shared with current semi-empirical MO techniques. 

Solvent effects on chemical equilibria and reactions have been an important issue in physical organic chemistry. Several empirical relationships have been proposed to characterize systematically the various types of properties in protic and aprotic solvents. One of the simplest models is the continuum reaction field characterized by the dielectric constant, e, of the solvent, which is still widely used. Taft and coworkers [30] presented more sophisticated solvent parameters that can take solute-solvent hydrogen bonding and polarity into account. Although this parameter has been successfully applied to rationalize experimentally observed solvent effects, it seems still far from satisfactory to interpret solvent effects on the basis of microscopic infomation of the solute-solvent interaction and solvation free energy. 

Electronic characteristics and their effects on the ability of side chains to engage in ionic bonding, covalent bonding, hydrogen bonding, van der Waals forces, and acid-base chemistry... 

Gerlt, J. A., Kreevoy, M. M., Cleland, W. W., and Frey, P. A., 1997. Understanding enzymic catalysis The importance of short, strong hydrogen bonds. Chemistry and Biology 4 259-267. 

The coordination chemistry of the large, electropositive Ln ions is complicated, especially in solution, by ill-defined stereochemistries and uncertain coordination numbers. This is well illustrated by the aquo ions themselves.These are known for all the lanthanides, providing the solutions are moderately acidic to prevent hydrolysis, with hydration numbers probably about 8 or 9 but with reported values depending on the methods used to measure them. It is likely that the primary hydration number decreases as the cationic radius falls across the series. However, confusion arises because the polarization of the H2O molecules attached directly to the cation facilitates hydrogen bonding to other H2O molecules. As this tendency will be the greater, the smaller the cation, it is quite reasonable that the secondary hydration number increases across the series. 

Hydrogen-bonded complexes are common throughout chemistry. They generally involve a hydrogen attached to a heteroatom (usually nitrogen or oxygen) interacting with another heteroatom. 

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