A Redox-Active Tetrathiafulvalene-Based 3D Covalent Organic Framework with scu Topology for Controllable Charge Transport.

Unlike 2D frameworks where conductivity is largely confined to in-plane transport, the scu topology offers 3D conduction pathways that enhance bulk charge mobility. When integrated with redox-active species like tetrathiafulvalene (TTF), the scu architecture promotes electron transfer across the 3D network, enabling tunable conductivity. This article presents the construction of a 3-periodic (4,8)-c covalent organic framework (COF), TU-48, adopting a twofold interpenetrated scu net, achieved through the integration of a tetratopic D 2h-symmetric rectangular TTF structural motif and an octatopic D 2h-symmetric quadrangular prism linker. TU-48 exhibits high structural order, well-defined porosity, and redox-responsive electrochemical behavior. The high-connectivity 3D COF configuration ensures effective access to TTF redox centers, enabling controlled iodine oxidation and resulting in electrical conductivities of 4.3 × 10-6 S cm-1 at 298 K and 1.8 × 10-4 S cm-1 at 393 K. By demonstrating how enhanced structural connectivity in TTF-bridged 3D covalent lattices enables improved charge-transport properties, this research fuels innovation in sustainable energy storage solutions and electronics.