The correlations between interaction and relative conformer energies of the different kJ/mol). The relative energy of the C 5 ion pair conformer (3.53 kJ.mol) is lower than that of the ion pair conformers of C 1 (4.03 kJ/mol) and C 2 (5.17 kJ/mol) and thus is expected to be more stable than the other two. However, the question why the C 5 ion pair conformer has less absolute interaction energy than C 1 and C 2 ion pair conformers is likely to be raised. From ). The results show that the greater the number of multiple H-bond interactions, the greater the absolute value of the interaction energy.