A theoretical study of epibatidine

A theoretical study of the conformational profile of epibatidine and its pr otonated form has been carried out using molecular mechanics (CVFF and CFF9 1), semiempirical (AM1) and ab initio (RHF/6-31G* and B3LYP/6-31G*) methods . Six minima have been found for the neutral molecule and four for the prot onated one with small rotational barriers between them. The stability of th e minima has been explained using the AIM methodology. Finally, the NMR shi eldings of the different conformers found have been calculated with the CIA O method and used to assign some of the ambiguous experimental signals.