Mutually independent pathways for one-to-two chemodosimetric recognition of Zn2+ and F− by a dimeric nickel(II) complex: A potential biomarker sensor for copper deficiency myelopathy

Abstract

Towards exploration of one-to-two unimolecular system, the applicability of a fluorescence silent Ni(II) based chemosensor, AR-1 comprised of NO2 donor Schiff base ligand towards “turn on” chromo-fluorogenic recognition of F− and Zn2+ over Cd2+via mutually independent pathways has been unveiled in the present work. The sensing phenomenon is very fast within ∼18 sec for Zn2+ and ∼24 sec for F− with the emergence of bright greenish cyan and yellowish green coloured fluorescence respectively. The detection threshold values were acquired to be 1.3 μM (388 ppb) for Zn2+ and 3.4 μM (887 ppb) for F−. UV–vis, fluorescence, mass spectroscopic and electrochemical investigation with theoretical DFT and TDDFT studies support the chemodosimetric sensing phenomenon. AR-1, characterized by single crystal X-ray data, is equally responsive towards solid state sensing of the targeted analytes. Moreover, it has also been employed towards preparation of three-input-two-output logic circuitry, which is unique of its kind in the relevant domain. Most interestingly, to the best of our knowledge, AR-1 is the first Ni(II) based Schiff base chemoreceptor, which has been effectively implemented for real-time detection of Zn2+ from complex bio-matrix, like serum upto 1.83 μM (544 ppb). This may give an indication of copper deficiency myelopathy (CDM), of which early diagnosis may reduce the risk of irreversible neurological damage.