Berlin 2005 – scientific programme
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MO: Molekülphysik
MO 15: Biomolecules II
MO 15.3: Talk
Friday, March 4, 2005, 17:30–17:45, HU 2097
Solvation of Protonated Biomolecular Building Blocks: IR spectra of Protonated Imidazole Clusters — •Horia-Sorin Andrei, Nicola Solca, and Otto Dopfer — Institut für Physikalische Chemie, Universität Würzburg, Am Hubland, 97074 Würzburg
Imidazole (Im) is a principal building block of many bioorganic compounds, such as the DNA bases adenine (A) and guanine (G) and the amino acid histidine (His). Because of its high proton affinity, Im is often protonated even at physiological pH values and acts in many enzymatic processes as a proton shuttle. Here, we report on IR spectra and quantum chemical calculations of ImH+-(H2O)n clusters to evaluate the properties of ImH+ under controlled microhydration conditions. Additional spectra recorded for ImH+-Ln with L=Ar, N2, and CH4 yield detailed information about the acidity of the NH protons of ImH+ in both nonpolar and polar environments.