Tailoring a Polyoxometalate-Based Metal–Organic Framework for Photocatalytic Oxidative Cross-Coupling Reactions to Synthesize Benzo(naphtho)thiazoles

Benzo(naphtho)thiazoles and their derivatives are widely used in optoelectronic materials, medicinal chemistry, and industry. Visible-light-induced photocatalytic cross-dehydrogenative coupling (CDC) reactions have emerged as a green and efficient alternative, but existing catalytic systems still suffer from limitations such as the high cost of precious metal catalysts, poor stability of organic-based catalysts, and low bond-formation efficiency. Herein, a photoactive polyoxometalate-based metal-organic framework (POMOF) catalyst, [Cu₂(BTIz)₃(H₂O)₅SiW₁₂O₄₀]·5H₂O (CuW-BTIz, BTIz = 4,7-bis(imidazolyl) benzothiazole), was synthesized by integrating the electron-acceptor polyanion [SiW₁₂O₄₀]⁴⁻ into a BTIz-based MOF. BTIz serves as a donor-acceptor-donor photosensitizer with extended visible-light absorption and efficient electron transfer capability, while [SiW₁₂O₄₀]⁴⁻ acts as an electron trap to promote charge separation via coordination interactions. Under white light irradiation at room temperature, CuW-BTIz exhibits excellent performance in the CDC reactions for synthesizing benzo(naphtho)thiazoles, achieving moderate-to-high yields. This work provides a promising heterogeneous photocatalytic strategy for the green and efficient synthesis of benzo(naphtho)thiazole derivatives.