Low Molecular Weight Gelators Based on Functionalized <span style="font-variant: small-caps">l</span>-Dopa Promote Organogels Formation

oleh: Demetra Giuri, Nicola Zanna, Claudia Tomasini

Format: Article
Diterbitkan: MDPI AG 2019-05-01

Deskripsi

We prepared the small pseudopeptide Lau-<span style="font-variant: small-caps;">l</span>-Dopa(OBn)<sub>2</sub>-<span style="font-variant: small-caps;">d</span>-Oxd-OBn (Lau = lauric acid; <span style="font-variant: small-caps;">l</span>-Dopa = <span style="font-variant: small-caps;">l</span>-3,4-dihydroxyphenylalanine; <span style="font-variant: small-caps;">d</span>-Oxd = (4<i>R</i>,5<i>S</i>)-4-methyl-5-carboxyl-oxazolidin-2-one; Bn = benzyl) through a number of coupling reactions between lauric acid, protected <span style="font-variant: small-caps;">l</span>-Dopa and <span style="font-variant: small-caps;">d</span>-Oxd with an excellent overall yield. The ability of the product to form supramolecular organogels has been tested with different organic solvents of increasing polarity and compared with the results obtained with the small pseudopeptide Fmoc-<span style="font-variant: small-caps;">l</span>-Dopa(OBn)<sub>2</sub>-<span style="font-variant: small-caps;">d</span>-Oxd-OBn. The mechanical and rheological properties of the organogels demonstrated solvent-dependent properties, with a storage modulus of 82 kPa for the ethanol organogel. Finally, to have a preliminary test of the organogels&#8217; ability to adsorb pollutants, we treated a sample of the ethanol organogel with an aqueous solution of Rhodamine B (RhB) for 24 h. The water solution slowly lost its pink color, which became trapped in the organogel.