Synthesis of a novel hydrazone-based compound applied as a fluorescence turn-on chemosensor for iron (III) and a colorimetric sensor for copper (II) with antimicrobial, DFT and molecular docking studies.

A. Adams, A.R. Sharmin, A.M. Patwary, E.G. William, K.M. Royhana, M.M. Mahmud, M.A. Haque, J. Uddin, and K. Morshin
Coppin State University,
United States

Keywords: chemosensor, Hydrazone–hydrazide, fluorescence


Hydrazone–hydrazide-based linkers perform a crucial role in environmental as well as biological fields. Such linkers are employed to detect exact metal ions at a minute level; hence, numerous probes are available. Even though thiophene-based molecules have a unique position in the medicinal arena, only very few chemo sensors are reported based on such a moiety. In this current work, a novel hydrazide–hydrazone-based fluorogenic molecule 5-bromo-2-hydroxy-N-[(1E)-1-(thiophen-2-yl) ethylidene]benzo hydrazide (L) has been successfully designed and synthesized. The sensing studies of L demonstrated a ratio metric as well as turn-on-enhanced fluorescence and colorimetric response toward Fe3+ and Cu2+ ions, respectively and it was observed to be insensitive toward various metal ions. The Job plots revealed that the binding stoichiometry of L and metal ions is 2:1. In addition, density functional theory (DFT) results strongly suggested that L can be used as a powerful colorimetric sensor for the detection of Cu2+ ions. In vitro antimicrobial activities of L were evaluated by disk diffusion and results revealed good antibacterial activities against E. coli. Further, molecular docking was executed with DNA gyrase (PDB ID: 1KZN) of E. coli and the calculated interaction energy value was found to be −7.7 kcal mol−1. Finally, molecular docking, fluorescence, colorimetry and the HOMO–LUMO energy gap of the compound can provide new insights into developing drugs and detecting metals in biomolecules.