Vertical decorative line
Research Center for Complex Molecular Systems and Biomolecules
Center for Biomolecules and Complex Molecular Systems   
Supported by the Ministry of Education, Czech Republic      
Decorative element
Decorative element
Decorative element Research | Papers | People | Events | Archive | Teach | Contact   
Decorative element
Empty gif
Empty space gif.
Abstract of the article
Empty gif Empty gif
On differences between hydrogen bonding and improper blue-shifting hydrogen bonding.

Zierkiewicz, W.; Jurecka, P.; Hobza, P., ChemPhysChem, 6 [4] 609 - 617 (2004)

Twenty two hydrogen-bonded and improper blue-shifting hydrogen-bonded complexes were studied by means of the HF MP2 and B3LYP methods using the 6-31G(dp) and 6-311++G(dp) basis sets. In contrast to the standard H bonding, the origin of the improper blue-shifting H bonding is still not fully understood Contrary to a frequently presented idea, the electric field of the Proton acceptor cannot solely explain the different behavior of H-bonded and improper blue-shifting H-bonded complexes. Compression of the hydrogen bond due to different attractive forces-dispersion or electrostatics-makes an important contribution as well. The symmetry-adapted perturbation theory (SAPT) has been utilized to decompose the total interaction energy into physically meaningful contributions. In the red-shifting complexes, the induction energy is mostly larger than the dispersion energy while, in the case of blue-shifting complexes, the situation is opposite. Dispersion as an attractive force increases the blue shift in the blue-shifting complexes as it compresses the H bond and, therefore, it increases the Pauli repulsion. On the other hand, dispersion in the red-shifting complexes increases their red shift.


<< Go back
Empty space gif.
Empty gif
Decorative element