Cobalt isatin-Schiff-base derivative of MOF as a heterogeneous multifunctional bio-photocatalyst for sunlight-induced tandem air oxidation condensation process

• Published in: Scientific reports Vol. 13; no. 1; p. 5115
• Main Authors: Rouzifar, Majid, Sobhani, Sara, Farrokhi, Alireza, Sansano, José Miguel
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 29-03-2023; Nature Publishing Group; Nature Portfolio
• Subjects: 639/638; 639/638/403; 639/638/403/933; Alcohols; Aldehydes; Aniline; Antibacterial activity; Catalysts; Cobalt; E coli; Energy conservation; Ethanol; Humanities and Social Sciences; Imidazole; Irradiation; multidisciplinary; Oxazoles; Oxidants; Oxidation; Oxidizing agents; Photocatalysis; Radiation; Science; Science (multidisciplinary); Spectrophotometry; Sunlight; Thiazoles
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-023-32241-z

A sunlight-induced tandem air oxidation-condensation of alcohols with
ortho
-substituted anilines or malononitrile for the efficient synthesis of benz-imidazoles/-oxazoles/-thiazoles, or benzylidene malononitrile catalyzed by Co-isatin-Schiff-base-MIL-101(Fe) as a heterogeneous multifunctional bio-photocatalyst is reported. In these reactions, Co-isatin-Schiff-base-MIL-101(Fe) acts both as a photocatalyst, and a Lewis acid to catalyze the reaction of the in-situ formed aldehydes with
o
-substituted anilines or malononitrile. A significant decrease in the band gap energy and an increase in the characteristic emission of MIL-101(Fe) after functionalization with cobalt Schiff-base according to the DRS analysis and fluorescence spectrophotometry, respectively, indicate that the photocatalytic effectiveness of the catalyst is associated primarily to the synergetic influence of Fe–O cluster and Co-Schiff-base. EPR results obviously pointed out that Co-isatin-Schiff-base-MIL-101(Fe) is capable of creating
1
O
2
and O
2
⋅−
as active oxygen species under visible light irradiation. Using an inexpensive catalyst, sunlight irradiation, air as a cost-effective and abundant oxidant, and a low amount of the catalyst with recoverability and durability in ethanol as a green solvent, make this methodology as an environmentally friendly process with energy-saving organic synthetic strategies. Furthermore, Co-isatin-Schiff-base-MIL-101(Fe) displays excellent photocatalytic antibacterial activity under sunlight irradiation against
E. coli, S. aureus
and
S. pyogenes.
Based on our knowledge, this is the first report of using a bio-photocatalyst for the synthesis of the target molecules.