Photochemistry of covalently bonded graphene oxide – Perylene diimide system for bacterial growth inhibition started by singlet oxygen

• Published in: Journal of photochemistry and photobiology. A, Chemistry. Chemistry., 2021-02, Vol.407, p.113058, Article 113058
• Main Authors: Peres, Rayana Martins, Brêda, Gabriela Coelho, Almeida, Rodrigo Volcan, Corrêa, Rodrigo José
• Format: Article
• Language: English
• Subjects: Escherichia coli; Graphene oxide; Photo-bactericidal; Singlet oxygen; UV-vis irradiation
• ISSN: 1010-6030; 1873-2666
• DOI: 10.1016/j.jphotochem.2020.113058

[Display omitted] •Graphene oxide modified with perylene diimide capable of generating singlet oxygen.•The material shows the potential to be applied as a bactericidal agent.•GO modification decreases excited-state deactivation of linked dyes. Two new composites containing perylene diimides derivates covalently bonded to graphene oxide were obtained and their antimicrobial properties were applied against Escherichia coli, a model of gram-negative bacteria. The perylene diimides were prepared by condensating perylene dianhydride with ethyldiamine (PEDI2) or decyldiamine (PEDI10) and then, a SOCl2 modified GO sample reacted with perylene diimides, originating the respective covalently bonded GO/PEDI2 and GO/PEDI10. Semi-empirical calculations with PM6-DH2X (MOPAC 2016) confirmed the photophysical results and showed that perylene diimides could form three different structures when bonded to GO: (1) parallel to GO, forming π-stacking interaction; (2) parallel to GO, but not superimposed π-systems (pns-π), and; (3) perpendicular to the GO molecular plane (T-shape). The photophysical studies showed that both GO/PEDI2 and GO/PEDI10 composites were able to generate singlet oxygen (1O2) when perylene diimides did not form π-stacking with GO. Finally, the photochemical reactivities of such covalently bonded composites were confirmed by the increased bacterial inhibition when E. coli (more than 80 %) is irradiated in the visible part of the electromagnetic spectrum when compared to dark conditions GO.