Super/hyperbasicity of novel diquinonimino derivatives of guanidine in gas phase

Abstract

In the present investigation, we are trying to design appropriate super/hyperbasic structures on the basis of guanidine and the application of electron-donating of substituted R groups, aromaticity stabilization of a seven-membered and two six-membered fused rings via the calculation of Proton Affinity (PA) and Gas-phase Basicity (GB), using Density Functional Theory (DFT). The results showed that the effective push-pull effect has been existed from R donating groups to guanidine moiety. In order to monitoring aromaticity alterations in the rings before and after protonation, Nucleus-independent Chemical Shift (NICS), Harmonic Oscillator Model of Aromaticity (HOMA), and Harmonic Oscillator Model of Electron Delocalization (HOMED) indexes were used. Results ascertained that all of the designed structures have the PA value further than superbasicity threshold and also even four structures offered PA values higher than hyperbasicity threshold (11, 13, 18, and 19).