A thiophene functionalized Hf(IV) organic framework for the detection of anti-neoplastic drug flutamide and biomolecule hemin and catalysis of Friedel-Crafts alkylation.

Development, rapid detection and quantification of anticancer drugs in biological samples are crucial for effective drug monitoring. The present work describes the design of a metal-organic framework (MOF) between Hf(IV) ion and 2-(thiophene-2-carboxamido)terephthalic acid linker (surface area = 571 m² g-1). Desolvated 1' displayed highly discriminative fluorescence sensing property for the anti-neoplastic drug flutamide and biomolecule hemin in aqueous medium in the presence of co-exiting biomolecules and ions. The MOF's response time for sensing flutamide and hemin was less than 5 s with low detection limits 1.5 and 0.08 nM respectively. Additionally, the MOF also demonstrated recyclability up to five cycles and maintained its sensing ability across different pH media, various water samples, and biological fluids. Experimental and theoretical analyses suggested photoinduced electron transfer and inner-filter effect in the presence of flutamide and Förster resonance energy transfer in the presence of hemin are most likely reasons behind the fluorescence quenching of MOF. Furthermore, the MOF demonstrated catalytic activity in Friedel-Crafts alkylation reactions, providing a 96% yield with slight decay in its activity over four uses. The enhanced activity of 1' is due to the functionalized thiophene moities through hydrogen bond donating sites, confirmed by series of control experiments.