A unique N-heterocyclic oligo(N,O-donor) salamo-Ni(II)-based probe for highly selective fluorescence detection of Cr2O72

Abstract

A unique fluorescent probe Ni-DAS was developed by a nitrogenous heterocyclic oligo(N,O-donor) salamo-based compound DAS. DAS exhibits AIE and ESIPT effects which are extremely infrequent in salamo-based multi-oxime compounds. In addition, Ni-DAS can be used as a fluorescent probe with high selectivity and sensitivity to recognize Cr₂O₇^2- in DMF with 80 % water content, which enhances the value of the probe for application in real environments, and outperforms most similar molecular fluorescence probes. The probe Ni-DAS can recognize Cr₂O₇^2- by oxidative hydrolysis of C = N bonds, which promotes further research on theory of C = N bond hydrolysis, and the binding ratio and recognition mechanism were verified and supported by relevant theoretical calculations (DFT & MESP). The experiments showed that the probe Ni-DAS can be used for ion detection in real environments. It provides a new strategy for the oxidative hydrolysis of C = N bond and the structure of salamo-based compounds with AIE nature, and offers new ideas for study ion recognition and acidity detection.

Keywords: AIE effect; C=N bond breakage; Cr(2)O(7)(2-); DFT calculation; Salamo-based probe.