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

Abstract

It 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 selfaccelerating 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 m 2 g À 1 , and good H 2 separation performance.

Bioinspired “Spindle Knot Effect” Integrated into Mixed-Matrix Nanofibrous Membranes for Highly Efficient Solar-to-Vapor Conversion

“…The poor processability of MOFs impedes the formation of the “spindle knot” by using MOFs alone. Fortunately, polymers of intrinsic microporosity (PIMs) exhibit remarkable processability for the successful preparation of spindle-knotted nanofibers, keeping high microporosity. − As such, it is anticipated that MOF and PIM as complementary pairs could be promising candidates to synchronically construct a high-performance solar steam evaporator based on the “spindle knot effect”, which has never been touched.…”