Xi'an Key Laboratory of Textile Chemical Engineering Auxiliaries, School of Environmental & Chemical Engineering, Xi'an Polytechnic University, Xi'an 710048, Shaanxi, P. R. China.
Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education, School of Chemistry & Chemical Engineering, Shanxi Normal University, Xi'an 710062, Shaanxi, P. R. China.
Inorg Chem. 2022 Sep 26;61(38):15213-15224. doi: 10.1021/acs.inorgchem.2c02459. Epub 2022 Sep 9.
How to accurately detect and efficiently sweep Cr(VI) from contaminated water has come into focus. Zirconium-based metal-organic frameworks (MOFs) play vital roles in water environmental chemistry due to excellent hydrolysis-resistant stability. However, as photochemical probes and photocatalysts, poor performances in detection sensitivity, selectivity, and photosensitiveness limit sole Zr-MOFs' applications. So, it is urgent to quest valid strategies to break through the dilemmas. Embedding luminous dyes into MOFs has been considered one of the most feasible avenues. Herein, a dual-emissive RhB@Zr-MOF with orange-yellow fluorescence has been assembled by in situ-encapsulating rhodamine B (RhB) into a zirconium-biquinoline-based MOF. Actually, within RhB@Zr-MOF, the aggregation fluorescence quenching (ACQ) effect of RhB molecules was effectively avoided. Notably, RhB@Zr-MOF exhibits a rapid fluorescence quenching response toward Cr(VI) ions with high selectivity, sensitivity, and anti-interference abilities. More interestingly, unlike the most widely reported fluorescence resonance energy transfer (FRET) between MOFs and encapsulated guest modules, photoinduced electron transfer from RhB to Zr-MOF has been confirmed by modeling the ground state and excited states of RhB@Zr-MOF using density functional theory (DFT) and time-dependent DFT (TD-DFT). The effective electron transfer makes RhB@Zr-MOF more sensitive in probing CrO and CrO ions with ultralow detection limit (DL) values of 6.27 and 5.26 ppb, respectively. Prominently, the detection sensitivity based on DL values has been increased about 6 and 9 times, respectively, compared with pristine Zr-MOF. Moreover, rather negative CB and positive VB potentials make RhB@Zr-MOF have excellent photochemical scavenging ability toward Cr(VI) and MO.
如何准确地检测和有效地从受污染的水中清除 Cr(VI)已成为焦点。锆基金属-有机骨架（MOF）由于具有优异的水解稳定性，在水环境保护化学中起着至关重要的作用。然而，作为光化学探针和光催化剂，其检测灵敏度、选择性和光敏性差限制了单一 Zr-MOF 的应用。因此，迫切需要寻求有效的策略来突破这些困境。将发光染料嵌入 MOF 中被认为是最可行的途径之一。在这里，通过将罗丹明 B（RhB）原位封装到基于锆双喹啉的 MOF 中，组装了具有橙黄色荧光的双发射 RhB@Zr-MOF。实际上，在 RhB@Zr-MOF 中，有效地避免了 RhB 分子的聚集荧光猝灭（ACQ）效应。值得注意的是，RhB@Zr-MOF 对 Cr(VI)离子表现出快速荧光猝灭响应，具有高选择性、灵敏度和抗干扰能力。更有趣的是，与最广泛报道的 MOF 和封装客体模块之间的荧光共振能量转移（FRET）不同，通过使用密度泛函理论（DFT）和时间相关的 DFT（TD-DFT）对 RhB@Zr-MOF 的基态和激发态进行建模，证实了光诱导电子从 RhB 到 Zr-MOF 的转移。有效的电子转移使 RhB@Zr-MOF 能够更灵敏地探测 CrO 和 CrO 离子，其检测限（DL）值分别低至 6.27 和 5.26 ppb。突出的是，与原始 Zr-MOF 相比，基于 DL 值的检测灵敏度分别提高了约 6 倍和 9 倍。此外，RhB@Zr-MOF 的 CB 和 VB 电位均为负值，使其具有出色的光化学清除 Cr(VI)和 MO 的能力。
