Highly sensitive conformational switching of ethane-bridged mono-zinc bis-porphyrin as an application tool for rapid monitoring of aqueous ammonia and acetone

The spectroscopic behavior of mono-zinc ethane-bridged bis-porphyrin (ZnH2Po2) was studied as a solid film upon deposition from a chloroform solution by means of the spin-coating method. The angular speed used during the deposition strongly influences the conformational arrangement of bis-porphyrin. A preferential arrangement as the anti- (opened) conformer was obtained when high speeds were used. The obtained thin film was successfully employed to detect ammonia and acetone as the relevant analytes in aqueous solutions. This was a result of the supramolecular interaction between each of these two compounds used and the bis-porphyrin active layer, inducing the corresponding conformational switching easily detectable by UV-vis absorption spectroscopy. The spectral variations of ZnH2Po2 were evident in the range of concentrations between 1 ppm and 20 ppm for both the analytes. This is particular important in light of the fact that ammonia and acetone concentrations are changed within this limit throughout the menstrual women's cycle, reaching their maximum during the fertility days. Hence, ZnH2Po2 can be effectively applied as a potential active layer for medical devices to monitor the hormonal variations during the women's menstrual cycle. Additionally, the reversible sensing mechanism with reusable up to 8 cycles, makes this ZnH2Po2 based active layer practically efficient