Tuning the Aggregation Performance by Varying the Substituent Position: Comparative Study of Neutral Bis-Urea Derivatives in Aqueous Medium

A set of three neutral bis-urea derivatives has been purposefully chosen to investigate the consequences of positional isomers on the aggregation performance. The comparative analysis based on the spectral study proved that all three isomers 1, 2 and 3 exhibit substantial aggregation behavior while the compound 2 is more potent in the formation and stabilization of aggregates. Variation in the aromatic core revises the directional property as well as steric effect which causes the diversity in morphology of aggregated species of 1, 2 and 3 and further validated by FESEM images as well as theoretical approach. Additional studies were also conducted to assess the influence of temperature, salt (NaCl), urea and pH on their aggregation properties to gain a deeper understanding on their relative aggregation aptitude and the results direct to the strong hydrogen bonding responsible for the aggregation phenomenon.