SCF-MO Conformational Analysis of Polycroconaine

Abinitio calculations at the STO-3Gbasis set level using GAUSSIAN 92 were conducted on the monomer unit of polycroconaine, a conducting polymer with conductive properties similar to several metals, in order to determine the most probable conformation of the monomer. We also compared the energy difference between the highest occupied and lowest unoccupied molecular orbitals. Successivecalculations were performed at dihedral angle intervals of 30° around the central bond of the monomer. Minimum energy was observed at 0° bond rotation, consistent with a theory that the polymer owes many of its conductive properties to a planar configuration in combination with extensive conjugation of the CC double bonds in the structure.