Theoretical Study of Long-Distance Electronic Coupling in H2C(CH2)n-2 CH2 Chains, n=3-16

The long-range electronic coupling in model chain alkyls H 2 C(CH 2 ) n-2 CH 2 , n=3-16, and 1,4-dimethyl-enecyclohexane has been investigated using ab initio molecular orbital theory to assess dependence of the results on basis set and method of calculation. Both anion and cation π couplings were examined. Basis sets ranging from minimal STO-3G to triple-zeta plus polarization were used, and diffuse orbitals were added to some of the basis sets. Small basis sets such as the split-valence 3-21G generally gave results in reasonable agreement with the larger basis sets