Entropy‐Enthalpy Compensation in Solvent Geometry Regulated Supramolecular Polymerization of Luminescent Napthalimide via a Non‐Cooperative, Isodesmic Mechanism

Abstract

AbstractSupramolecular polymers of π‐conjugated systems are an important class of materials with fascinating functions and properties originated from the dynamic behavior and highly ordered molecular organizations. Here, a donor‐π‐acceptor based functionalized luminescent napthalene monoimide (NMI) undergoes J‐type self‐assembly by non‐covalent interactions via a non‐cooperative, isodesmic mechanism to form supramolecular 1D nanowire. The fundamental insights into the thermodynamics regulating the supramolecular polymerization were derived through the fitting of the isodesmic model to variable temperature UV/Vis data in linear (dodecane) and nonliner hydrocarbon (decalin) based solvents. This shows a significant role of entropy‐enthalpy compensation in solvent geometry‐regulated formation and stabilization of supramolecular polymer. Furthermore, we have quantitively estimated the influence of solvent geometry and found that NMI forms stronger self‐assembly and spontaneous gel in linear hydrocarbon based solvent compared to nonliner one and thereby substantially increases the degree of polymerization in linear hydrocarbon solvent (dodecane). This is accredited to the effective influence of the linear hydrocarbon solvent molecules in the polymerization process by favourable van der waals interactions with the peripheral alkyl chains of the NMI monomers in contrast to unfavourable interaction of nonliner hydrocarbon solvent due to geometry mismatch.