Fully zwitterionic diaminobenzoquinonediimines promoted by cyanoaromatic N-substituents

2,5-Diamino-1,4-benzoquinonediimine (DABQDI) derivatives possessing two electron-withdrawing aromatic N-substituents can potentially exhibit a zwitterionic ground state in lieu of the expected canonical structure. It was previously shown that use nitroaromatics groups (EWG) could yield quantitative formation tautomer DABQDI polar solvents, while mixture and forms present low polarity solvents. In this work, we report replacement nitro-containing EWG by weaker nitrile ones prevents species apolar solvents for benefit tautomer. This counterintuitive observation is rationalized with theoretical calculations, which points out fully electronic structure nitrile-containing arises from absence possible intramolecular hydrogen bonding between cyanoaromatic N-substituent N–H proton bridge form.