STUDIES ON N-METALLO IMINES - DEPENDENCE OF CHEMICAL-SHIFT OF THE C-13 IMINIC CARBON FROM THE NATURE OF THE NITROGEN SUBSTITUENT

A preliminary study on the influence of the nitrogen substituent on th e electrophilicity of the iminic carbon by evaluation of its C-13 chem ical shift is reported. Two series of N-substituted imines, derived fr om benzaldehyde and lactic aldehyde and bearing, directly linked to th e nitrogen, Al, Si, B, C, S, N, O groups, are examined. The dependence of C-13 iminic chemical shift is shown to be a function of mesomeric interaction and frontier orbital energetic factors as emphasized by ab initio calculations.