Gauche and Diaxial Strain in Cyclohexane Rings
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 epimeric cyclohexane
rings bearing different dimethyl substitution patterns. You will then compare
the strain energies and/or enthalpies of formation in each pair, to evaluate
trends in preference for cis/trans and axial/equatorial geometry
in these systems.
Procedure. Build and optimize the following molecules.
In the results table, record the method used, strain energies, enthalpy
of formation (if available). Visualize the molecule and examine the force
field output (similar data not available in MO analyses) to identify major
sources of steric strain, if present.
Benchmarks. Enthalpies of formation are recorded in the results
section below, where available.
Copyright 1995 by Paul M. Lahti. All Rights Reserved.