Toward Sustainable Gel Chemistry: Supramolecular Gelation of Amino Acid Derivatives in Green Solvents

Herein, we report a systematic study on the formation of supramolecular gels in selected organic green solvents using a small library of low-molecular-weight gelators derived from l-Dopa and l-tyrosine. Five green solvents (γ-valerolactone, dimethyl carbonate, diethyl carbonate, isopropanol, and isoamyl alcohol) were selected to span different chemical classes and physicochemical properties relevant to sustainable processing. By modulating the aromatic content and side-chain length, structure–property relationships governing the gelation behavior were identified: the intrinsic lipophilicity of the gelator, expressed by its logP value, emerged as a key factor in the self-assembly outcome. Indeed, the bolaamphiphilic Dopa-based derivatives, bearing aliphatic spacers and the highest value of logP, display markedly enhanced gelation performance and predominantly thermoreversible networks in the selected solvents. Overall, this work expands the applicability of green solvents in supramolecular gel chemistry and provides molecular design guidelines for sustainable materials.