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Recognition of Polymer Terminus by Metal-Organic Frameworks Enabling Chromatographic Separation of Polymers.

Unlike commonly used molecular recognition tech-niques, recognition of polymer structures requires an addi-tional aspect of extremely high recognition ability, by which marginal structural differences can be identified in a large polymer chain. Herein we show that metal-organic frameworks (MOF) can recognize polymer terminal struc-tures, thus enabling the first reported chromatographic sepa-ration of polymers. End-functionalized polyethylene gly-cols (PEGs) are selectively inserted into the MOF chan-nel, the insertion kinetics being dependent on the projec-tion size of the PEG terminus. This size-selective inser-tion mechanism facilitates precise discrimination of end-functionalized PEGs using liquid chromatography (LC). A MOF-packed column thus provides an efficient and easily accessible method for the separation of such end-functionalized polymers using conventional LC systems.