Department of Chemical & Biomolecular Engineering, National University of Singapore, Singapore, 117585, Singapore.
Department of Chemistry, National University of Singapore, Singapore, 117543, Singapore.
Nat Commun. 2017 Oct 26;8(1):1142. doi: 10.1038/s41467-017-01293-x.
Molecular rotors have played an important role in recent materials chemistry. Although several studies on functional materials containing molecular rotors have been reported for fluorescence sensing, this concept has yet to be realized in two-dimensional (2D) materials. Here we report the preparation of all-carbon, π-conjugated 2D porous organic nanosheets, named NUS-24, which contain flexible tetraphenylethylene (TPE) units as the molecular rotors. NUS-24 nanosheets exhibit high stability, large lateral size, and ultrathin thickness (2-5 nm). The dynamic TPE rotors exposed on the surface of NUS-24 nanosheets can be restricted in the aggregated state with different water fractions, which is reminiscent of the aggregation-induced emission mechanism, thereby leading to the size-selective turn-on fluorescence by volatile organic compounds. Significantly, the ultrathin 2D nanosheets and its composite membranes show much higher sensitivity and selectivity toward Fe ions and nitro-containing compounds sensing, suggesting their potential applications in explosive detection and environmental monitoring.
分子转子在现代材料化学中发挥了重要作用。尽管已有几篇关于含分子转子的功能材料的荧光传感研究报告，但这一概念尚未在二维（2D）材料中实现。在这里，我们报告了全碳、π共轭 2D 多孔有机纳米片的制备，该纳米片命名为 NUS-24，其含有作为分子转子的柔性四苯乙烯（TPE）单元。NUS-24 纳米片具有高稳定性、大的横向尺寸和超薄厚度（2-5nm）。表面暴露的动态 TPE 转子在不同水分数的情况下可以被限制在聚集态，这让人联想到聚集诱导发射机制，从而导致挥发性有机化合物的尺寸选择性开启荧光。值得注意的是，超薄的 2D 纳米片及其复合材料膜对 Fe 离子和含硝基化合物的传感表现出更高的灵敏度和选择性，这表明它们在爆炸物检测和环境监测方面具有潜在的应用。
