Tautomeric Equilibria, I.
Methodology
Molecular Mechanics (Force Field) MNDO/AM1 PM3
(Semiempirical MO)
Techniques Used
Building, Optimization. Analysis of Bonding Parameters.
Output Analysis
Abstract. You will build pairs of tautomeric molecules
to predict the most stable isomer. Since tautomeric equillbria are often
finely poised and solvent dependent, this will act as a test of the capability
of any given method to give an experimentally correct result for a gas phase
molecular calculation. As an option, solvent field corrections may be included
in the calculation if these are available.
Procedure. Build and optimize the following molecules. In the
results table record the method used, force held energies. and enthalpy
of formation (if available) for each system. Compare your predicted stability
trends to benchmark results.
Benchmarks. Known relative stabilities are recorded in the following
table with relative enthalpies of formation where lmown.
