Synthesis, Characterization, and Dual Functional Properties of Coumarin-Based Hybrids for Biological and Optical...

Area of Science:

• Medicinal Chemistry
• Organic Synthesis
• Materials Science

Background:

• Heterocyclic compounds containing coumarin, benzimidazole, and benzothiazole nuclei are recognized for their significant biological and pharmacological activities.
• Hybrid molecules integrating these privileged scaffolds offer potential for enhanced therapeutic and material properties.

Purpose of the Study:

• To develop an efficient synthetic route for novel coumarin-benzimidazole and coumarin-benzothiazole hybrid compounds.
• To systematically evaluate the synthesized compounds for antibacterial, antioxidant, and photoluminescent properties.
• To investigate structure-activity relationships and explore potential applications in theranostics and optoelectronics.

Main Methods:

• Mild reaction conditions were employed for the synthesis of 11 hybrid compounds (6 coumarin-benzimidazole, 5 coumarin-benzothiazole derivatives).
• Antibacterial activity was assessed against *Staphylococcus aureus*.
• Antioxidant activity was evaluated using the DPPH radical scavenging assay.
• Density functional theory (DFT) calculations and multivariate statistical methods (PCA) were used for computational analysis.
• Photoluminescence properties were measured, with emission spectra recorded.

Main Results:

• The synthesis yielded 11 hybrid compounds with moderate to good yields (14-60%).
• Derivatives 19 and 26 displayed moderate antibacterial activity against *Staphylococcus aureus* (MICs of 500 and 250 μg·mL^-1).
• Derivatives 26 and 33 exhibited strong antioxidant activity (DPPH radical scavenging rates of 89% and 72%).
• Structure-activity relationship studies indicated that substituents at position 7 of the coumarin nucleus enhance antioxidant activity.
• Promising photoluminescence characteristics were observed, with emissions ranging from 446 to 502 nm.
• DFT and PCA identified molecular volume and bond order as key determinants of biological activity.

Conclusions:

• The developed synthetic strategy efficiently produces coumarin-based hybrid compounds with diverse biological and optical properties.
• Specific derivatives demonstrate potential as antibacterial and antioxidant agents.
• The photoluminescent properties suggest utility in optoelectronic devices and theranostic applications.
• Structural modifications are crucial for optimizing the performance of these hybrid molecules for future biomedical and technological advancements.