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 ZnII 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 K04.10±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 ZnII coordination centre to bind to two adenine molecules through hydrogen bonding with their imine and hydrazone protons. Copyright © 2012 Springer Science+Business Media, LLC.