[Preparation and application of heteroporous covalent organic frameworks as gas chromatography stationary phases].

Chromatographic separation stands as a cornerstone technique in modern analytical chemistry， playing an indispensable role in critical areas such as chemical purification， environmental monitoring， and pharmaceutical analysis. With the increasing complexity of analytical samples， particularly regarding the efficient separation of structurally similar isomers， higher requirements have been imposed on chromatographic stationary phases. Traditional porous materials such as zeolites and silica show limited tunability in pore size distribution and surface chemistry， making it difficult to meet the urgent need for high-resolution and rapid separation of complex mixtures. Therefore， the exploration of novel ordered porous materials with precisely tunable pore structures and functionalities has become a frontier research direction in separation science. Covalent organic frameworks （COFs）， as a category of crystalline porous polymers， possess great application potential in separation science. Their prominent advantages mainly include designable periodic frameworks， easily modified functional groups， and precisely tunable pore sizes. These intrinsic merits render COFs promising candidates for next-generation chromatographic separation media. In this work， a novel strategy is proposed to regulate the pore structure of COFs via rational topological design， aiming to improve their gas chromatographic performance toward challenging isomer separation. This is achieved by constructing heteroporous COFs that integrate distinct pore size distributions within a single， ordered framework. To realize this strategy， a heteroporous COF designated as ET-COF was successfully constructed. It was synthesized via a reversible imine condensation reaction between a