Ab initio study of possible and preferred basic site(s) in polyfunctional N1,N1-dimethyl-N2-cyanoformamidine

Energies of protonation and of hydrogen-bond complex formation of neutral and protonated forms with one water molecule were studied by means of ab initio calculations for polyfunctional nitrogen push-pull base, Me(2)N-CH=N-C=N. Two potential basic sites, the N-imino and N-cyano were considered. Calculations with the 6-31G* basis set showed that the N-cyano site is more basic than the N-imino one for both reactions, proton-transfer and hydrogen-bonding in the gas-phase, whereas in water solution, the PCM model indicated the N-imino as the preferred basic site.