Ab initio SCF-MO study of the molecular structures of aminomethanol, aminesulfonic acid and N-methyl-sulfamate

Abstract

Ab initio MO studies at the STO-3G and the 4-31G level are reported for aminomethanol (H₂NCH₂OH), aminesulfonic acid (H₂NSO₃H) and N-methylsulfamate (CH₃NHSO₃^-). The potential energy surface of aminomethanol is compared with that of methanediol and the origin of "reverse anomeric effect" is discussed. The potential energy surface of aminesulfonic acid is compared with that of aminomethanol and sulfuric acid. The favored conformations are analysed in terms of the interaction of polar bonds and the dipoles on the atoms. Various contributions to the potential energy are analysed by decomposing the potential into three term Fourier components. A general survey is made of the effect of bond length and bond angle optimisation on the conformational energies of various anomeric systems.