CHED 1356 |
| Proton transfer, like in a reaction HA → A- + H+, is arguably the most important process in chemistry, biochemistry and materials science. For the proton-exchanging groups that cannot be subjected to experimental pH measurement – e.g. an enzyme cofactor not suitable for molecular spectroscopic measurements – electronic structure calculation can provide an estimate of the proton exchange power in vacuum and in simulated solvent. In recent past calculations of this type have been highly intensive and the calculated pKa values have been at best very crude estimates. With the continuing development of algorithms and codes a priori calculations of intrinsic Brřnsted acidities are becoming more manageable, even on small microcomputers. It does not take a visionary to predict that calculations of absolute pKa values will in time become a standard molecular laboratory procedure. Here we present a procedure for a priori pKa calculation of a protonated water complex – a small and relatively simple molecular species whose electronic structure calculation demand modest computing power – which employs the knowledge and tools of the basic statistical thermodynamics and thus provide a useful project in undergraduate physical chemistry course.
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Undergraduate Research Poster Session: Physical Chemistry
2:00 PM-4:00 PM, Monday, March 26, 2007 Hyatt Regency Chicago -- Riverside Center, Poster
Division of Chemical Education |