Self‐Accelerating Diels–Alder Reaction for Preparing Polymers of Intrinsic Microporosity

Abstract

AbstractIt is a formidable challenge in polycondensation to simultaneously construct multiple covalent bonds to prepare double‐stranded polymers of intrinsic microporosity (PIMs) with fused multicyclic linkages. To the best of our knowledge, this is the first study to develop a self‐accelerating Diels–Alder reaction for successfully preparing double‐stranded PIMs with fused multicyclic backbone structures. A self‐accelerating Diels–Alder reaction was developed based on the [4+2] cycloaddition of sym‐dibenzo‐1,5‐cyclooctadiene‐3,7‐diyne (DIBOD) and ortho‐quinone compounds. In this reaction, the cycloaddition of ortho‐quinone with the first alkyne of DIBOD activates the second alkyne, which reacts with ortho‐quinone at a rate constant 192 times larger than that of the original alkyne. Using this self‐accelerating reaction to polymerize DIBOD and spirocyclic/cyclic difunctional ortho‐quinone monomers, a novel stoichiometric imbalance‐promoted step‐growth polymerization method was developed to prepare PIMs. The resultant PIMs possess intrinsic ultramicropores with pore sizes between 0.45 to 0.7 nm, high specific surface areas above 646 m2 g−1, and good H2 separation performance.