Seal Nilanjan, Mondal Partha Pratim, Palakkal Athulya S, Pillai Renjith S, Neogi Subhadip
Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India.
Inorganic Materials & Catalysis Division, CSIR-Central Salt & Marine Chemicals Research Institute (CSMCRI), Bhavnagar, Gujarat 364002, India.
ACS Appl Mater Interfaces. 2023 Nov 29;15(47):54397-54408. doi: 10.1021/acsami.3c11197. Epub 2023 Nov 15.
Stimuli-responsive emission color modulation in fluorescent metal-organic frameworks (MOFs) promises luminescence-ink-based security application, while task-specific functionality-engineered pores can aid fast-responsive, discriminative, and ultralow detection of harmful organo-aromatics in the aqueous phase. Considering practical applicability, a self-calibrated fluoro-switch between encrypted and decrypted states is best suited for antiforgery measures, whereas image-based monitoring of organo-toxins by repetitive and handy methods over multiple platforms endorses in-field sensory potential. Herein, we constructed a mixed-ligand based chemically stable and bilayered-pillar MOF from -NH-hooked pyridyl linker and tricarboxylate ligand that embraces negatively charged [Cd(μ-OH)(COO)] node and shows pore-space-partitioning by nitrogen-rich flanked organic struts. Owing to the presence of a self-calibrating triazolylamine moiety-grafted auxiliary linker, this anionic MOF delineates reversible and multicyclic fluoro-swapping between protonated-encrypted and deprotonated-decrypted domains in the alternative presence of acid and base. Such pH-triggered, site-specific luminescence variation is utilized to construct highly regenerative anticounterfeiting labels for vivid acronym encryption. The intense fluorescence signature of the material is further harnessed in extremely selective and quick responsive sensing of harmful feed additive roxarsone (ROX) and dichloran (DCNA) pesticide in highly recyclable fashion with significant quenching and nanomolar limits of detection (ROX: 52 ppb; DCNA: 26.8 ppb). Notably, the ultrasensitive fluoro-detection of both these organo-toxins is successfully demonstrated via a handy paper-strip method as well as on the vegetable surface for real-time monitoring. Comprehensive density functional theory studies validate the electron transfer mechanism through redistribution of molecular orbital energy levels by each of the targeted analytes in this electron-rich framework besides evidencing MOF-analyte supramolecular interactions.
荧光金属有机框架材料（MOFs）中刺激响应发射颜色调制有望实现基于发光墨水的安全应用，而特定任务功能工程化的孔有助于在水相中对有害有机芳烃进行快速响应、区分性和超低检测。考虑到实际适用性，加密和解密状态之间的自校准荧光开关最适合防伪措施，而通过在多个平台上重复且便捷的方法对有机毒素进行基于图像的监测则支持现场传感潜力。在此，我们从-NH连接的吡啶基连接体和三羧酸配体构建了一种基于混合配体的化学稳定且双层柱状MOF，其包含带负电荷的[Cd(μ-OH)(COO)]节点，并通过富氮侧翼有机支柱显示出孔隙空间分区。由于存在自校准的三唑基胺部分接枝的辅助连接体，这种阴离子MOF在酸和碱交替存在的情况下，在质子化加密和解质子化解密域之间描绘出可逆的多环荧光交换。这种pH触发的、位点特异性的发光变化被用于构建用于生动首字母加密的高度可再生防伪标签。该材料强烈的荧光特征还被用于以高度可回收的方式对有害饲料添加剂洛克沙胂（ROX）和二氯萘醌（DCNA）农药进行极其选择性和快速响应的传感，具有显著的猝灭和纳摩尔检测限（ROX：52 ppb；DCNA：26.8 ppb）。值得注意的是，通过便捷的纸条方法以及在蔬菜表面成功展示了对这两种有机毒素的超灵敏荧光检测，以进行实时监测。综合密度泛函理论研究除了证明MOF-分析物超分子相互作用外，还通过该富电子框架中每种目标分析物的分子轨道能级重新分布验证了电子转移机制。
