Search

Guided by a second‐sphere interaction strategy, we fabricated a Tb(III)‐based metal—organic framework (MMCF‐4) for turn‐on sensing of methyl amine with ultra‐low detection limit and high turn‐on efficiency. MMCF‐4 features lanthanide nodes shielded in a nonacoordinate geometry along with secondary coordination spheres that are densely populated with H‐bond interacting sites. Nonradiative routes were inhibited by binding‐induced rigidification of the ligand on the second coordination sphere, resulting in luminescence amplification. Such remote interacting mechanism involved in the turn‐on sensing event was confirmed by single‐crystal X‐ray diffraction and molecular dynamic simulation studies. The design of both primary and secondary coordination spheres of Tb(III) enabled the first turn‐on sensing of organic amines in aqueous conditions. Our work suggests a promising strategy for high‐performance turn‐on sensing for Ln‐MOFs and luminous materials driven by other metal chromophores. [ABSTRACT FROM AUTHOR]

Single-dye-doped self-referenced ratiometric nanoprobe with two well-resolved fluorescence bands has been rationally designed and developed for selectively imaging of hypochlorous acid in lysosomes of living cells. • A single-dye-based self-referenced ratiometric nanoprobe (SSRN) for imaging lysosomal HClO is developed. • The SSRN exhibits two well-resolved fluorescence bands (∼130 nm). • 3The SSRN shows fast response time, high sensitivity and selectivity. The design of novel ratiometric nanoprobes with two well-resolved fluorescence bands for accurate imaging of lysosomal hypochlorous acid (HClO) is significant to understand its biological and pathological behaviors. Herein, we develop a single-dye-doped self-referenced ratiometric nanoprobe (SSRN) for imaging of HClO in lysosomes under a single-wavelength excitation (λ ex = 405 nm). The referenced unit (benzothiazole moiety) and HClO-responsive unit (rhodamine B) are integrated into the single dye (HB-Py) to achieve the self-referenced ratiometric effect. The well-dispersed SSRN are prepared by a simple coprecipitation of the morpholine moiety modified amphiphilic polymers (CO-720-MA) and HB-Py. Of note, the two well-resolved fluorescence bands (∼130 nm) of SSRN could provide accurate imaging of analyte in live cells. Additionally, other distinct merits with SSRN are also simultaneously realized, including high water solubility, high sensitivity (detection limit: 52 nM), excellent selectivity, good biocompatibility and excellent photostability. Significantly, benefiting from the morpholine moiety, this nanoprobe SSRN can specially locate lysosomes and enable ratiometric imaging of exogenous/endogenous HClO in lysosomes. [ABSTRACT FROM AUTHOR]

We report the inaugural experimental investigation of covalent organic frameworks (COFs) to address the formidable challenge of SO2 detection. Specifically, an imine‐functionalized COF (SonoCOF‐9) demonstrated a modest and reversible SO2 sorption of 3.5 mmol g−1 at 1 bar and 298 K. At 0.1 bar (and 298 K), the total SO2 uptake reached 0.91 mmol g−1 with excellent reversibility for at least 50 adsorption‐desorption cycles. An isosteric enthalpy of adsorption (ΔHads) for SO2 equaled −42.3 kJ mol−1, indicating a relatively strong interaction of SO2 molecules with the COF material. Also, molecular dynamics simulations and Møller–Plesset perturbation theory calculations showed the interaction of SO2 with π density of the rings and lone pairs of the N atoms of SonoCOF‐9. The combination of experimental data and theoretical calculations corroborated the potential use of this COF for the selective detection and sensing of SO2 at the sub‐ppm level (0.0064 ppm of SO2). [ABSTRACT FROM AUTHOR]