A Redox-Active Tetrathiafulvalene-Based Three-Dimensional Covalent Organic Framework with scu Topology for Controllable Charge Transport

Unlike two-dimensional (2D) frameworks where conductivity is typically restricted to in-plane transport, scu topology offers three-dimensional (3D) conduction pathways, enhancing bulk conductivity. When integrated with redox-active species like tetrathiafulvalene (TTF), the scu structure promotes electron transfer across the 3D network, enabling tunable conductivity. This study presents the construction of a 3-periodic [8+4]-connected COF, TU-48, adopting a 2-fold interpenetrated scu net, achieved through the integration of a tetratopic D2h-symmetric rectangular TTF structural motif and an octatopic D4h-symmetric quadrangular prism linker, displaying high structural order, well-defined porosity, and tunable electrochemical functionality. The high-connectivity 3D COF configuration optimizes access to redox centers, enabling controlled iodine oxidation and achieving an electrical conductivity of up to 1.8 × 10-4 S cm-1 at 393 K. Enhancing structural connectivity in TTF-bridged 3D covalent lattices, this research fuels innovation in sustainable energy storage solutions and electronics.