Preparation of Naphthalenediimide-Decorated Electron-Deficient Photochromic Lanthanide (III)-MOF and Paper Strip as Multifunctional Recognition and Ratiometric Luminescent Turn-On Sensors for Amines and Pesticides

Detecting toxic amine and pesticide contamination in the environment is one of the most pressing issues for environmental sustainability. In this work, two 3D Ln-BINDI complexes [Ln = Eu (1), Sm (2); H4BINDI (N, N'-bis(5-isophthalic acid)-1,4,5,8-naphthalenediimide)] have been designed and synthesized. Crystal structure of [Eu2(BINDI) (NO3)2(DMA)4]·2DMA (complex 1) featuring the lvt topology was determined by X-ray single-crystal diffraction. A multi-functional ratiometric luminescence sensor benefitting from π-electron-deficient NDI moieties and f-f transition characteristics of lanthanide Eu3+ ions for complex 1 has been investigated. Markedly, complex 1 exhibit completely different selective fluorescence ratiometric turn-on responses and pretty high sensitivity behaviors to aromatic amines (OPD), aliphatic amines (n-BA), and pesticides (TBZ), respectively, which are driven by interactions between the electron-donating amino group and acceptor NDI site, contributing to complex 1 as a potential ratiometric luminescent turn-on sensor for practical environmental applications. A PVA/1@paper strip can be used as a potential size selectivity sensor for the practical detection of aliphatic amine vapors in the environment through visual chromic fluorescence enhancement. Because NDIs can undergo one-electron reduction to form stable NDI· free radicals, solid complex 1 can visually distinguish different kinds of amines by selective amine-specific color changes and has the photochromic property of erasable inkless printing.