Electronic structure of phenyl-N,N-dimorpholinomethanes

The electronic structure of dimorpholinomethane and II phenyl derivatives w as studied by He I photoelectron spectroscopy and AMI quantum chemical calc ulations. The pi -system of the phenyl ring reacts weakly with the molecula r orbitals of dimorpholinomethane. Mutual electronic effects of the dimorph oline and phenyl fragments are estimated. It is shown that for most title c ompounds, HOMO is localized on the nitrogen atoms of dimorpholinomethane an d is independent of the type of substituent in the phenyl ring. An exceptio n is dimethylaminophenyl-N,N-dimorpholinomethane whose first ionization pot ential (7.31 eV) is much lower than that for other compounds (8.15-8.53 eV) due to electron withdrawal front the 3 pi (b(1)) MO of the phenyl ring. Th e relationship between the first ionization potentials and the effective co rrosion inhibiting property of the compounds is discussed.