Unlocking the chromatographic potential of emerging hydrogen-bonded/metal-organic frameworks as advanced functional...

Hydrogen/metal bonded organic frameworks (HOFs/MOFs), with their high porosity and tunable structures, demonstrate broad application prospects as chromatographic separation materials. However, MOF particles often suffer from limited separation efficiency, whereas HOFs tend to exhibit insufficient stability under repeated elution owing to the weak nature of hydrogen bonds, both of which pose significant challenges to a wide range of applications. Therefore, developing a composite that integrates the rigid framework of MOFs with the dynamic recognition features of HOFs is highly desirable to overcome these challenges, achieving both high separation performance and superior stability.

This study designed a novel HOF-102/ZIF-67@SiO₂ composite stationary phase to overcome the respective limitations of individual MOF and HOF materials. The incorporation of HOF-102 mitigates the peak tailing phenomenon caused by strong non-specific interactions with exposed metal sites in ZIF-67. Meanwhile, the underlying ZIF-67 acts as a rigid scaffold that structurally supports the HOF-102 layer, effectively preventing framework collapse during repeated chromatographic elution. Specifically, HOF-102/ZIF-67@SiO₂ was prepared using an in situ growth method, where a ZIF-67 layer was first constructed on the aminated silica surface, followed by the assembly of 6,6',6″,6‴-(pyrene-1,3,6,8-tetrayl)tetrakis(2-naphthoic acid) to form the outer HOF-102 layer. The HOF-102/ZIF-67@SiO₂ stationary phase demonstrated excellent separation performance across multiple chromatographic modes, and the retention mechanism was investigated through density functional theory calculations. Furthermore, its practical application value was confirmed through the successful separation and detection of target pollutants in complex real-world samples.

This study represents the first application of HOF/MOF composite as a promising stationary phase by synergistically combining the structural rigidity of ZIF-67 with the dynamic recognition capability of HOF-102. The developed HOF-102/ZIF-67@SiO₂ not only serves as an effective tool for environmental monitoring applications but also offers a conceptual framework for designing next-generation chromatographic systems.