A tunable ratiometric pH sensor based on phenanthro[9,10-d]imidazole covalently linked with vinylpyridine

Abstract

A rational design of the novel phenanthro[9,10-d]imidazole based pH sensing fluorophore PITP was developed, in which phenanthroimidazole acts as a donor and pyridine acts as an acceptor. Various spectral studies confirm that the protonation occurs at two different nitrogen centres, each of which produces an observable color change depending on the pH of the buffer solution. DFT calculations also support the experimental results. We show that PITP can be used as a ratiometric and colorimetric pH sensor in the acidic region.