Constructing Crystalline Porous Polyacetylene Frameworks via Catalyst-free Solid-state Cross-linking in Confined Space

A ‘confined space’ provides a unique environment to regulate the crystallization thermodynamics and kinetics by confining the reactants in the restricted space dimensions. Solid-state crystal-to-crystal transitions in confined space are controlled by the preassembly of molecules in crystal lattice and occur inside the lattice. Herein we report the first case of construction of crystalline porous polyacetylene frameworks (PPFs) through solid-state cross-linking of acetylenic groups-bridged 2D crystalline covalent organic frameworks (COFs) in spatially limited systems. Specifically, this transformation is thermally induced yielding PPFs with superlative properties like outstanding enhancement in crystallinity, specific surface area and stability. We further demonstrate the PPFs as high conductivity polymers after iodine doping. This work underscores the opportunity in using lattice-constrained solid-state cross-linking to develop more versatile and feature-rich polyacetylene frameworks.