Table 1.

Total and relative energies for the 15 tested structures. Energies were calculated using the B3LYP method and 6-311G basis set. Zero point energy corrections were applied. The displayed ΔE represents the energy difference compared to the structure with lowest energy value (assigned as 0) of each structural group. Groups are represented by Structures 2–3, 4–5, 6–7, 8–10, 11–12, and 13–15

Structure	Electronic+thermal energy at 298 K (kcal/mol)	ΔE(kcal/mol)
2	−349121.24	16.1
3	−349137.30	0
4	−315491.38	0
5	−267529.07	47962.3
6	−444844.96	12.3
7	−444857.24	0
8	−195089.64	0
9	−195080.37	9.3
10	−195077.75	11.9
11	−469491.61	0
12	−469481.97	9.6
13	−219739.58	0
14	−219730.34	9.2
15	−219727.71	11.9