Synthesis, crystal structures and studies on Hg2+ sensing by the diazo derivatives of sulfathiazole and sulfamethoxazole

Diazocoupling of sulfathiazole and sulfamethoxazole with 2,4-pentanedione led to the syntheses of compounds R1 and R2. These were fully characterized by single crystal X-ray diffraction studies in conjunction with UV-visible, IR, H-1 NMR, and mass spectral studies. Both the compounds were further screened for their possible use in metal ion recognition. Interestingly, compound R1 showed a selective naked-eye response for Hg2+, while R2 did not give a color change for any metal ions. These results can be understood in terms of a solvent-assisted low-energy absorption band in R1 that disappeared upon interaction with Hg2+. This absorption band was not observed in the case of compound R2 that consequently failed to show any naked-eye color change in the presence of metal ions. [GRAPHICS] .