Facts and reality of multi-component organic ionic-cocrystals of di-topic acid–base conjugates†

In this study, three ionic-cocrystals of N-((10-chloroanthracen-9-yl)methyl)-3-(1H-imidazolium-1-2yl)propan-1-ammonia (chloroanthraimmida) and 3,5-pyridinedicarboxylic acid (H₂35pdc) together with and without diiodo-tetrafluorobenzene are described. Variations in the protonation and deprotonation on the parent ditopic acid–base conjugate partners were observed. The energy considerations on different proton-transferred forms and the observed form of three multi-component ionic-cocrystals of di-topic acid–base conjugates revealed that the crystallised forms adopted closely related intermediate forms but with different proton-transferred states of the multi-component ionic-cocrystals. The halogen-bonds were used to construct two compositionally different ionic-cocrystals from the same acid–base conjugate pair.