Direct Imaging of Co-CUK-1 Framework with HO Guests.

The flexible architectural design of metal clusters and organic ligands attributes Metal-Organic Frameworks (MOFs) as one of the most versatile materials. Host-guest interactions contribute to this versatility, highlighting the need for a fundamental understanding of host frame-guest molecule units. Herein, ab-initio calculations elucidate the spatial distribution of HO guest molecules (guests) within [101] honeycomb channel of Co-CUK-1, where the HO guests are 1D aligned with the highest superposition density. In situ heating Raman spectroscopy demonstrates that HO guests within the Co-CUK-1 frame behave like a vapor phase, maintaining phase stability even when heated to 120 °C. Scanning Transmission Electron Microscopy (STEM) enables the identification of both the Co-CUK-1 frame and the HO guests in [101] honeycomb channel. Correlative Light and Electron Microscopy (CLEM) further reveals the intrinsic insulative nature of the Co-CUK-1 frame, along with extrinsic in-gap states caused by HO adsorption. By integrating ab-initio calculations, in situ heating Raman spectroscopy, and atomic-scale investigations via STEM and CLEM, this study establishes a comprehensive structural analysis of MOFs-materials that are highly versatile yet extremely sensitive to electron beam exposure.