An infrared study of the interaction between ethyl N-(diphenylmethylene)glycinate with proton donors: comparison with N-benzylidenemethylamine

Abstract

MARLEEN RUYSEN and T H~R~S EZEEGERS-HCYSKENS. Can. J. Chem. 64, 2305(1986.The interaction between ethyl N-(dipheny1methylene)gylcinate (DPG) and hydroxy proton donors or pyrrole has been investigated by ir spectrometry. The equilibrium constants, enthalpies, and entropies of complex formation have been determined in carbon tetrachloride solution and compared with the data obtained for the complexes involving N-benzylidenemethylamine and the same proton donors. The ir spectra studied mainly in the V O H , V C = N , VC=,, and uc-, regions suggest that hydrogen bond formation occurs at the N atom of the imino group and at the 0 atom of the carbonyl group. The results are discussed in terms of the basicity at the two acceptor sites and of the accessibility of the lone pair of electrons. The ir spectra of the solid adduct of DPG with HCI show that protonation takes place on the N atom. The protonated structure is possibly stabilized by an intramolecular hydrogen bond.