The Effects of Substituent Position and Orientation on the Structures and Dipole Moments of the Cyanocyclohexanes Using Density Functional Theory Calculations

Publication date: Available online 21 October 2019Source: Computational and Theoretical ChemistryAuthor(s): Kyle D. McNamara, Robert W. ZoellnerAbstractThe effects of position and orientation (axial/equatorial) on the structures and dipole moments of all possible cyano-substituted cyclohexanes were examined using B3LYP/6-311++G**. All optimized molecules exhibited the chair conformation; molecules exhibiting dipole moments ≥6.00 D were examined to determine the effect of substituent position and orientation on the dipole moment. Axial substituents had a greater effect than did equatorial on the dipole moment. For conformer pairs, axial substituents produced higher energy conformers, indicating that equatorial substituents lowered steric interference. Intramolecular non-bonded distances between co-facial axial/axial and vicinal axial/equatorial cyano-groups did not support the idea of greater axial steric demand. The ranges, but not the magnitudes, of ring C-C-C angles were influenced the atoms vicinal to the central carbon atom of the angle. Patterns in the highest occupied and lowest unoccupied molecular orbital energies may provide a basis from which specific cyanocyclohexanes may be “tuned” for electron-acceptor properties.Graphical abstract

Source: Computational and Theoretical Chemistry - October 22, 2019 Category: Chemistry Source Type: research