Near-Field Infrared Nanospectroscopy Reveals Guest Confinement in Metal-Organic Framework Single Crystals
Near-Field Infrared Nanospectroscopy Reveals Guest Confinement in Metal-Organic Framework Single Crystals
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DOI：
10.1021/acs.nanolett.0c02839
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发表时间：
2020-10-14
期刊：
影响因子：
10.8
通讯作者：
Tan, Jin-Chong
中科院分区：
文献类型：
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作者：
Moslein, Annika F.;Gutierrez, Mario;Tan, Jin-Chong
金属有机框架（MOF）可以为分子客体封装提供卓越的孔隙率，可用于传感、气体存储、药物输送和光电子学等新兴应用。然而，实现此类应用程序的核心是成功地将功能客户纳入主机框架内。在这里，我们首次证明了散射型扫描近场光学显微镜（s-SNOM）和纳米傅里叶变换红外（nanoFTIR）光谱的可行性，与密度泛函理论（DFT）计算相结合，揭示了Guest@MOF系统的振动特性。通过探测单个 MOF 晶体，我们查明了局部分子振动，从而为纳米尺度上的主客体相互作用提供了新的线索。我们的策略不仅证实了发光客体分子成功封装在单晶的多孔主体框架中，而且还进一步提供了一种新的方法，用于纳米级分辨的物理和化学识别广泛的框架材料和设计用于高级应用的多孔系统。
Metal-organic frameworks (MOFs) can provide exceptional porosity for molecular guest encapsulation useful for emergent applications in sensing, gas storage, drug delivery, and optoelectronics. Central to the realization of such applications, however, is the successful incorporation of a functional guest confined within the host framework. Here, we demonstrate, for the first time, the feasibility of scattering-type scanning near-field optical microscopy (s-SNOM) and nano-Fourier transform infrared (nanoFTIR) spectroscopy, in concert with density functional theory (DFT) calculations to reveal the vibrational characteristics of the Guest@MOF systems. Probing individual MOF crystals, we pinpoint the local molecular vibrations and, thus, shed new light on the host-guest interactions at the nanoscale. Our strategy not only confirms the successful encapsulation of luminescent guest molecules in the porous host framework in single crystals but also further provides a new methodology for nanoscale-resolved physical and chemical identification of wide-ranging framework materials and designer porous systems for advanced applications.