ABSTRACT
Herein, we report the design and synthesis of an amphiphilic flavin analogue as a robust low molecular weight gelator involving minimal structural modification. Four flavin analogues were evaluated for their gelation capabilities and the flavin analogue with antipodal positioning of the carboxyl and octyl functionalities was found to be the most efficient gelator with the minimum gelation concentration being as low as 0.03 M. A wide range of solvents were used for gelation studies suggesting its widespread applicability. Morphological, photophysical and rheological characterization studies were performed to fully characterize the nature of the gel. Interestingly, reversible multiple stimuli responsive sol-gel transition was observed with changing pH and redox activity, while metal screening showed specific transition in the presence of ferric ions. The gel was able to differentiate between ferric and ferrous species with well-defined sol-gel transition. The current results potentially offer a redox-active flavin-based material as a low molecular weight gelator for the development of next-generation materials.
ABSTRACT
A bioinspired mimic for the stabilization of hydroperoxyflavin intermediate formation was designed and investigated for monooxygenase like catalytic properties. A suitable peptide appendage was covalently linked to the C7-position of the neutral isoalloxazine core to synthesize Fl-G, Fl-F, Fl-P, and Fl-ßA analogues. While the presence and identity of the peptide appendage were found to be crucial for catalytic efficiency, corroborative observations were made from theoretical studies as well, supporting the precise conformational and accessibility requirements for the stabilization of the key hydroperoxyflavin intermediate. A simple yet elegant flavopeptide model (Fl-G) was found to achieve almost quantitative catalytic efficiency compared to the control flavin analogue without a peptide appendage.
