An asymmetric salamo-type fluorescent chemosensor for efficient recognition of Cu2+ and B4O72ˉ ions.

• Successfully synthesized a salamo-type probe NBS for detecting Cu2+ and B 4 O 7 2ˉ. • The additions of Cu2+ and B 4 O 7 2ˉ have opposite fluorescence behavior on NBS. • The detection mechanisms were proposed based on experimental and theoretical researches. A novel salamo-type fluorescent probe NBS (5-(N,N′-diethylamino)-2,2′-[ ethylenedioxybis (nitrilomethylidyne)]phenolnaphthol) for selectively recognition of Cu2+ and B 4 O 7 2ˉ was successfully synthesized. According to the Cu2+ recognition experiment, the probe NBS underwent a coordination process with Cu2+, leading to fluorescence quenching. Theoretical analysis of the recognition mechanism was conducted through DFT calculations. The binding ratio of NBS to Cu2+ was further determined to be 1:1 through high-resolution mass spectrometry. The limit of detection (LOD) of NBS for Cu2+ was calculated to be 3.57 × 10−8 M, and the association constant (K a) was 5.45 × 104 M −1. In addition, the probe NBS can also be used for selective detection of B 4 O 7 2ˉ, which was theoretically analyzed through molecular electrostatic potential. The limit of detection (LOD) of NBS for B 4 O 7 2ˉ was calculated to be 7.13 × 10−8 M, and the association constant was 5.66 × 104 M −1. At the same time, the probe can also quantitatively detect Cu2+ in water samples. A novel asymmetric salamo-type fluorescent probe NBS for detecting Cu2+ and B 4 O 7 2ˉ was successfully synthesized. In a mixed solvent DMF : H 2 O (9:1, V/V, pH=7.2), the NBS probe exhibits good selectivity for Cu2+ and B 4 O 7 2ˉ. The detection limit (LOD), quantification limit (LOQ), and association constant (Ka) of the NBS probe for detecting Cu2+ and B 4 O 7 2ˉ were determined. In addition, based on high-resolution mass spectrometry, Job's plots, DFT calculations, and molecular electrostatic potential analysis, reasonable mechanisms for the interaction between the probe NBS and Cu2+ and B 4 O 7 2ˉ were proposed. Meanwhile, the probe NBS can also be used for quantitative detection of Cu2+ in water samples. [Display omitted] [ABSTRACT FROM AUTHOR]