Vyhledávat v databázi titulů je možné dle ISBN, ISSN, EAN, č. ČNB, OCLC či vlastního identifikátoru. Vyhledávat lze i v databázi autorů dle id autority či jména.
Projekt ObalkyKnih.cz sdružuje různé zdroje informací o knížkách do jedné, snadno použitelné webové služby. Naše databáze v tuto chvíli obsahuje 2915976 obálek a 882571 obsahů českých a zahraničních publikací. Naše API využívá většina knihoven v ČR.
The nature of the hydrogen bond : outline of a comprehensive hydrogen bond theory | |||||
|
|
Autor: Gilli, Gastone AnotaceHydrogen bond (H-bond) effects are known: it makes sea water iquid, joins cellulose microfibrils in trees, shapes DNA nto genes and polypeptide chains into wool, hair, muscles or enzymes. Its true nature is less known and we may still wonder why O-H...O bond energies range from less than 1 to more than 30 kcal/mol without apparent reason. This H-bond puzzle is re-examined here from its very beginning and presented as an inclusive compilation of experimental H-bond energies and geometries.New concepts emerge from this analysis: new classes of systematically strong H-bonds (CAHBs and RAHBs: charge- and resonance-assisted H-bonds); full H-bond classification in six classes (the six chemical leitmotifs); and assessment of the covalent nature of strong H-bonds. This leads to three distinct but inter-consistent models able to rationalize the H-bond and predict its strength, based on classical VB theory, matching of donor-acceptor acid-base parameters (PA or pKa), or shape of the H-bond proton-transfer pathway.Applications survey a number of systems where strong H-bonds play an important functional role, namely drug-receptor binding, enzymatic catalysis, ion-transport through cell membranes, crystal design and molecular mechanisms of functional materials. Dostupné zdroje
| ||||