218
N. Tshilande and L. Mammino
check whether these symmetrical inputs yield symmetrical outputs on optimization,
above all in view of possible influences by the bulky BDE ring system, which is not
symmetric with respect to the plane of ring A. In the case of the rotation by 180°,
only one rotation is possible for each bond; thus, the bonds denoted by 2, 4, 6, 8 and
10 (Fig. 4) can rotate by 180° to the side of R
and those denoted by 3, 5, 7, and 9
can rotate by 180° to the other side with respect to R
.
The next subsections consider relevant molecular properties individually. Two sets
of ESI tables are provided for each property: a set of three tables showing the values
for all the calculated conformers of each of the three molecules (HF results) and a
set of three tables showing the values for the calculated conformers with different
geometries of R and the same geometry of ABDE (HF, DFT and MP2 results). Within
each set, the tables correspond to the MYRA, c-DBPO and t-DBPO sequence; since
this sequence remains the same for all cases, it is not repeated in the presentation of
each set.
3.3.2 Conformational Preferences in Vacuo
Overall, 123 conformers were calculated for MYRA and 115 conformers for each of
the two DBPO isomers. Tables S6–S8 report the relative energies of the calculated
conformers of the three molecules; Figs. S3, S5 and S7 show the geometries of the
calculated conformers having the same geometry of R and different geometries of
ABDE for MYRA, c-DBPO and t-DBPO respectively, and Figs. S4, S6 and S8
show the geometries of the conformers having different geometries of R and the
same geometry of ABDE. The absolute energies values show that the energy of the
lowest energy conformer of t-DBPO is 1.843 kcal/mol lower than the energy of the
lowest energy conformer of c-DBPO, suggesting greater stability of the trans isomer.
For the information about the energetics to be complete, Tables S9–S11 report
the relative energies corrected for ZPE (sum of electronic and zero-point energies),
the relative Gibbs free energies (sum of electronic and thermal free energy), and the
corresponding corrections, for representative lower-energy conformers of the three
molecules, and Figs. S22–S24 compare their trends. The ZPE corrections (kcal/mol)
are close for all the conformers of the same molecule: 453.64–454.51 for MYRA,
476.32–477.20 for c-DBPO and 476.07–476.92 for t-DBPO. The thermal corrections to the Gibbs free energy have the following ranges: 405.03–408.96 for MYRA,
425.05–431.51 for c-DBPO and 425.16–426.50 for t-DBPO. For MYRA, the values
of the uncorrected relative energies, ZPE-corrected relative energies and relative free
energies are close for the first nine lowest energy conformers, and for conformers #
27–39 (with these numbers referring to increasing uncorrected relative energies, as
used to denote conformers in Fig. S22), whereas they show significant differences
for most of the # 10–26 conformers. The latter are the conformers whose uncorrected
relative energies are so close as to give a nearly horizontal line in the graph, whereas
the corrected ones differ. In the case of c-DBPO and t-DBPO, the trends of uncorrected and corrected energy values are similar and the values for the same conformer
are close.
N. Tshilande and L. Mammino
check whether these symmetrical inputs yield symmetrical outputs on optimization,
above all in view of possible influences by the bulky BDE ring system, which is not
symmetric with respect to the plane of ring A. In the case of the rotation by 180°,
only one rotation is possible for each bond; thus, the bonds denoted by 2, 4, 6, 8 and
10 (Fig. 4) can rotate by 180° to the side of R
and those denoted by 3, 5, 7, and 9
can rotate by 180° to the other side with respect to R
.
The next subsections consider relevant molecular properties individually. Two sets
of ESI tables are provided for each property: a set of three tables showing the values
for all the calculated conformers of each of the three molecules (HF results) and a
set of three tables showing the values for the calculated conformers with different
geometries of R and the same geometry of ABDE (HF, DFT and MP2 results). Within
each set, the tables correspond to the MYRA, c-DBPO and t-DBPO sequence; since
this sequence remains the same for all cases, it is not repeated in the presentation of
each set.
3.3.2 Conformational Preferences in Vacuo
Overall, 123 conformers were calculated for MYRA and 115 conformers for each of
the two DBPO isomers. Tables S6–S8 report the relative energies of the calculated
conformers of the three molecules; Figs. S3, S5 and S7 show the geometries of the
calculated conformers having the same geometry of R and different geometries of
ABDE for MYRA, c-DBPO and t-DBPO respectively, and Figs. S4, S6 and S8
show the geometries of the conformers having different geometries of R and the
same geometry of ABDE. The absolute energies values show that the energy of the
lowest energy conformer of t-DBPO is 1.843 kcal/mol lower than the energy of the
lowest energy conformer of c-DBPO, suggesting greater stability of the trans isomer.
For the information about the energetics to be complete, Tables S9–S11 report
the relative energies corrected for ZPE (sum of electronic and zero-point energies),
the relative Gibbs free energies (sum of electronic and thermal free energy), and the
corresponding corrections, for representative lower-energy conformers of the three
molecules, and Figs. S22–S24 compare their trends. The ZPE corrections (kcal/mol)
are close for all the conformers of the same molecule: 453.64–454.51 for MYRA,
476.32–477.20 for c-DBPO and 476.07–476.92 for t-DBPO. The thermal corrections to the Gibbs free energy have the following ranges: 405.03–408.96 for MYRA,
425.05–431.51 for c-DBPO and 425.16–426.50 for t-DBPO. For MYRA, the values
of the uncorrected relative energies, ZPE-corrected relative energies and relative free
energies are close for the first nine lowest energy conformers, and for conformers #
27–39 (with these numbers referring to increasing uncorrected relative energies, as
used to denote conformers in Fig. S22), whereas they show significant differences
for most of the # 10–26 conformers. The latter are the conformers whose uncorrected
relative energies are so close as to give a nearly horizontal line in the graph, whereas
the corrected ones differ. In the case of c-DBPO and t-DBPO, the trends of uncorrected and corrected energy values are similar and the values for the same conformer
are close.