Supramolecular Polymeric Chemosensor for Biomedical Applications: Design and Synthesis of a Luminescent Zinc Metallopolymer as a Chemosensor for Adenine Detection

Adenine is an important bio-molecule that plays many crucial roles in food safety and biomedical diagnostics. Differentiating adenine from a mixture of adenosine and other nucleic bases (guanine, thymine, cytosine, and uracil) is particularly important for both biological and clinical applications. A neutral Zn^II metallosupramolecular polymer based on acyl hydrazone derived coordination centres (P1) were generated through self-assembly polymerization. It is a linear coordination polymer that behaves like self-standing film. The synthesis, ¹H-NMR characterization, and spectroscopic properties of this supramolecular material are reported. P1 was found to be a chemosensor specific to adenine, with a luminescent enhancement. The binding properties of P1 with common nucleic bases and nucleosides reveal that this supramolecular polymer is very selective to adenine molecules (~20 to 420 times more selectivity than other nucleic bases). The formation constant (K) of P1 to adenine was found to be log K?=?4.10?±?0.02. This polymeric chemosensor produces a specific response to adenine down to 90?ppb. Spectrofluorimetric and ¹H-NMR titration studies showed that the P1 polymer allows each Zn^II coordination centre to bind to two adenine molecules through hydrogen bonding with their imine and hydrazone protons.