Rapid and reliable ratiometric fluorescence detection of nitro explosive 2,4,6-trinitrophenol based on a near infrared (NIR) luminescent Zn(II)-Nd(III) nanoring.

A nine-metal Zn(II)-Nd(III) nanoring with a diameter of about 2.3 nm was constructed for the rapid and ratiometric fluorescence detection of explosive 2,4,6-trinitrophenol at the ppm level. [Display omitted] • 2,4,6-Trinitrophenol (TNP) is detected firstly by a NIR luminescent high-nuclearity d-4f nanomolecular sensor. • The ratiometric fluorescence detection of TNP is fast and reliable. • The ratiometric fluorescence detection of TNP is highly sensitive and selective. Rapid and quantitative detection of 2,4,6-trinitrophenol (TNP) is very crucial for homeland security, military application, and environment protection. Herein, a nine-metal Zn(II)-Nd(III) nanoring 1 with a diameter of 2.3 nm was constructed by the use of a long-chain Schiff base ligand, which shows ratiometric fluorescence response to TNP with high selectivity and sensitivity. The fluorescence sensing behavior of 1 to TNP is expressed by a first-order equation I 1060nm / I 560nm = -0.0128*[TNP] + 0.9723, which can be used to quantitatively analyze TNP concentrations in solution. The limits of detection (LODs) to TNP based on the ligand-centered (LC) and Nd(III) emissions of 1 are 5.93 μM and 3.18 μM, respectively. The fluorescence response mechanism to TNP is attributed to the competitive absorption effect and photoinduced electron transfer (PET). The luminescence quenching of 1 is dominated by static process. [ABSTRACT FROM AUTHOR]