Proceedings - Interdisciplinary Center for Nanotoxicity

40
Conference on Current Trends in Computational Chemistry 2009
31+G** basis sets. The minima of the potential surface were found by relaxing the geometric
parameters with the standard optimization methods. Analytical force constants
a) trans‐1 (0.0) b) trans‐2 (0.9 kcal/mol)
c) cis‐1 (4.3 kcal/mol) d) cis‐2 (4.9 kcal/mol)
Figure 2. Optimized B3LYP/6‐31+G** geometries and relative energies (in parentheses) for four
stable conformers of I.
were derived and harmonic vibrational frequencies were calculated using all investigated
theoretical levels. All calculations have been done without any restrictions for structures.
We have considered four stable conformers of I, the optimized B3LYP/6‐31+G**
geometries of these conformers with their relative energies (in parentheses) are presented in
Fig. 2. The most stable by theoretical calculations is trans‐1 conformer (Fig. 2a), the next on
stability is trans‐2 conformer (Fig. 2b) which differs from trans‐1 by the orientation of metoxy
group. The energy difference between them is about 0.9 Kcal/Mol, and their relative
concentrations are ~ 78% : 22%. Corresponding theoretical dipole moments of these
conformers are equal to 4.19 and 6.07 D for trans‐1 and trans‐2, accordingly. Two cis‐
conformers presented on Figs 2c and 2d have significantly higher energies in comparison with
trans‐forms.