Non-traditional intrinsic luminescence of amphiphilic-based ionic liquids from oxazolidines: Interaction studies in phosphatidylcholine-composed liposomes and BSA optical sensing in solution

• Published in: Journal of molecular liquids Vol. 313; p. 113525
• Main Authors: Borba, Laíse Costa, Griebeler, Cassiana Herzer, Bach, Mariana Ferrari, Barboza, Cristina Aparecida, Nogara, Pablo Andrei, da Rocha, João Batista Teixeira, Amaral, Simone Schneider, Rodembusch, Fabiano Severo, Schneider, Paulo Henrique
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-09-2020
• Subjects: Intrinsic luminescence; Ionic liquid; Oxazolidine; Intrinsic luminescence; Oxazolidine; Ionic liquid
• ISSN: 0167-7322; 1873-3166
• DOI: 10.1016/j.molliq.2020.113525

This study presents the synthesis in good overall yields of oxazolidine-based ionic compounds obtained from protected l-serine followed by an esterification reaction with bromoalcohols and a reaction with 1-methylimidazole in acetonitrile under reflux. These compounds present in ethanol solution an absorption maxima located around 210 nm, resulting in a non-traditional intrinsic luminescence observed between 350 and 390 nm. According to calculations performed at CAM-B3LYP/6-311++G(d,p), these redshifted emission bands would be related to the increased polarity of these structures (μ > 10 D). Fluorescence titration experiments were also performed, and the partition coefficient in PC liposomes was determined, presenting high values (Kp ~ 104). In addition, their interaction with bovine serum albumin (BSA) in a phosphate buffer solution (PBS) was investigated, presenting a suppression mechanism where the imidazolium seems to play a fundamental role. Docking simulations were also performed to better understand the observed BSA suppression mechanism upon the addition of oxazolidines.
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•Photoactive quiral oxazolidine-imidazolium based ILs synthesized in good yields•Non-traditional intrinsic luminescence observed•Photophysical properties of these ILs were successfully explored for BSA sensing.•Docking simulations contributed to understand the BSA suppression mechanism.