Aryl-substituted TEEs, TVEs, and their hybrids are fluorescent, with some exhibiting aggregation-induced emission enhancement. The utilization of TEE–TVE hybrids as building blocks for larger acyclic, through/cross-conjugated hydrocarbon frameworks is also established. Their participation in pericyclic reaction cascades, leading to sp3-rich polycycles, is demonstrated. Most substituted TVE–TEE hybrids are found to be significantly more robust compounds than their unsubstituted counterparts, enhancing the prospects of their deployment in conducting materials and devices. The synthesis permits the controlled preparation of many previously inaccessible structures, including examples with different substituents on each of the four branching arms. This work thus advances COFs with high stability as potential universal CSPs for chromatography that are otherwise hard or impossible to produce.Ī general synthetic approach to molecular structures that are hybrids of tetraethynylethylene (TEE) and tetravinylethylene (TVE) is reported. The resolution performances are comparable to and the versatility is superior to those of the most widely used commercial chiral columns, showing promises for practical applications. The COF-packed HPLC and GC columns show excellent complementarity and each affords high resolution, selectivity, and durability for the separation of a wide range of racemic compounds, including amino acids, esters, lactones, amides, alcohols, aldehydes, ketones, and drugs. Chiral crown ethers are periodically aligned within the COF channels, allowing for enantioselective recognition of guest molecules through intermolecular interactions. Both COFs have the same 2D layered porous structure but channels of different sizes and display high stability under different chemical environments including water, organic solvents, acids, and bases.
We demonstrate here that two olefin-linked covalent organic frameworks (COFs) featuring chiral crown ether groups can be general CSPs for extensive separation not only in GC but also in normal-phase and reversed-phase HPLC. High-performance liquid chromatography (HPLC) and gas chromatography (GC) over chiral stationary phases (CSPs) represent the most popular and highly applicable technology in the field of chiral separation, but there are currently no CSPs that can be used for both liquid and gas chromatography simultaneously.
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