Strategic synthesis of [NiII]2FeIII heterotrimetallic chemophores for selective sensing of poultry feed-additive organo-arsenicals (PFAs)

Abstract

Two novel heterotrimetallic complexes, [(Ni²⁺)₂Fe³⁺L₂] (designated as VBCMERI-1 and VBCMERI-2), were synthesized and fully characterized as effective chemosensors for poultry feed-additive organoarsenicals (PFAs). These complexes exhibit selective chromo-fluorogenic responses in aqueous media via the ligand displacement mechanism triggered by PFAs. The binding process was substantiated experimentally by means of FT-IR, UV-vis, photoluminescence, and cyclic voltammetry studies and further supported theoretically by reduced density gradient (RDG) analysis. The selective and sensitive detection capabilities were successfully demonstrated in real-world matrices, including poultry blood, flesh, and soil samples. Notably, VBCMERI-2 enabled efficient turn-on fluorogenic detection of As³⁺ in tobacco products. Additionally, the resulting VBCMERI–PFA adducts showed cross-reactive behavior toward Al³⁺, allowing the construction of a 6-input/8-output molecular logic gate system that emulates visual perception. These findings position VBCMERI-1 and VBCMERI-2 as promising multifunctional sensory platforms for environmental and food safety monitoring.