Interplay of hydrogen bonding in deciding the conformers of psilocin:
Computational insights
Abstract
Conformational analysis of psilocin, a psychedelic molecule revealed two
stable conformers designated as conformer-A and B which were 4.97
kcal/mol apart in energy among many other high energy conformers. AIM
analysis revealed that the conformer-A (global minimum) is stable due to
intramolecular H-bond formation between ethyl amine nitrogen and indolic
hydroxyl group. This is in contradiction to earlier X-ray crystal
studies of this molecule reported in literature. Dimers of both
conformer-A and B were studied utilizing DFT method and it was observed
that even in the dimer of conformer-A the intramolecular H-bond energy
dominates over the intermolecular H-bond. Other calculations namely NBO,
FMO, charge analysis, ESP mapping corroborated the AIM results in a
significant manner. The spectroscopic study including UV, 1H-NMR and
vibrational modes calculation were found to be in good agreement with
the data reported in literature.