Fine-Tuning of Saponification-Triggered Gelation by Strategic Modification of Peripheral Substituents: Gelation Regulators

A pioneering approach towards controlling the efficiency of saponification assisted gelation in ethyl ester based ZnII-complexes have been described. Using four new ester containing bis-salen ZnII complexes (C1-C4) involving different para- dye-azo phenyl substituted ligands it has been clearly shown that gelation efficiency is greatly influenced by electronic effect of the substituents (-H, C1; -CH3, C2; -NO2, C3 and -OCH3, C4). Morphological, photophysical, and rheological investigations corroborated well with the experimental observations and established that gelation efficiency enhanced coherently with electron withdrawing characteristics of the substituents (C4 < C2 < C1 < C3) which has also been supported by DFT studies.