Development of heterocyclic 2,7-diamino-3-phenylazo-6-phenylpyrazolo[1,5-a]pyrimidine as antimicrobial agent and selective probe for UV–visible and colorimetric detection of Hg2+ ions

Mercury is considered as a highly toxic metal ion due to its lethal effects on humans and the ecological system. The increasing level of antimicrobial resistance are threatening to the ecosystem, public health and economy. The development of new environmentally safe organic molecules can be a potential cure for both of the above-mentioned problems. Herein, we have synthesized 2,7-diamino-3-phenylazo-6-phenylpyrazolo[1,5-a]pyrimidine (PPD) as a new hetero-cyclic ligand, act as a selective Hg2+ ion chemosensor. The developed sensing probe PPD exhibited limit of detection (LOD) 1.31 × 10−6 M, and limit of quantitation (LOQ) 4.39 × 10−6 M in the linear range2.7–45.65 × 10−6 M with good association affinity of 1.668x 104 M−1for Hg2+ ions. Interestingly, the synthesized heterocyclic motif (PPD) provided a significant colorimetric change from colorless to yellow upon binding with Hg2+ ions. Moreover, the developed probe exhibited tremendous antimicrobial activity against seven bacterial strains and one fungal strain. Cytotoxic studies on normal cell lines were also carried out for this compound which proved that compound is non-toxic (91–100 % cell survival) and can be applied to living system for mercury poisoning detection.