Abstract
Abstract The doubling of the NMR signals of the isopropyl methyl protons in 2,4-dichlorophenyl methyl isopropylphosphoramidate has been shown to be due to a difference in chemical shift of the two methyl groups. This difference is ascribed to a steric hindrance to rotation about the N-C bond which enhances the inherent nonequivalence due to molecular asymmetry. Studies of the changes in chemical shift difference with changes in temperature, concentration and solvent show the steric hindrance to be due to intermolecular hydrogen bonding. The NMR data are correlated with infrared spectra of the phosphoramidate obtained under similar conditions; these spectra support the hydrogen bonding hypothesis. Possible hydrogenbonded species are discussed.
Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
