WO₃-ZnS Photocatalyzed Synthesis of Some Substituted Benzimidazoles as Effective Agents against Gastrointestinal Cancer

Benzimidazoles, a class of nitrogen-containing heteroaromatic compounds, play a crucial role in the development of various important drugs. These compounds exhibit diverse biological functionalities. In this study, a novel and environmentally friendly photocatalytic route is proposed for the production of benzimidazoles. This method involves the oxidation of alcohol to aldehyde using air as the oxidant under visible-light conditions. Subsequently, fast condensation with o-phenylenediamine takes place, leading to the formation of 2-substituted benzimidazoles. The key mediator in this process is a newly developed photocatalyst called WO3-ZnS, which is activated by a commercial green laser light with a wavelength of 535 nm. To characterize the nanocomposite, several techniques including FT-IR, XRD, EDS, and FE-SEM were employed. These analyses provided valuable insights into the structure and properties of the nanocomposite. Moreover, Tauc's method was utilized to estimate the optical band gap of the photocatalyst. The proposed photocatalytic process involves a radical pathway including reactive species such as.O-2(-) and OH center dot, along with h(+). Stability and reusability experiments confirmed the reproducibility of the nano-photocatalyst in the reaction medium. Furthermore, the primarily invitro cellular toxicity of WO3-ZnS nanoparticles was evaluated using the HCT-116 human cancer cell line through MTT (3-(4,5-dimethylthiazol-2-yl)2,5-diphenyl-2H-tetrazolium bromide) assay. The results demonstrated a significant reduction in cell viability, indicating the cytotoxicity of the nanoparticles against these cancerous cells. This finding highlights the potential of the synthesized nanoparticles as effective agents for combating gastrointestinal cancer.