An Electrically Conductive Tetrathiafulvalene-Based Hydrogen-Bonded Organic Framework

Recent advancements in the development of conductive metal-organic frameworks (MOFs) and covalent organic frameworks (COFs) havesparked interest in a variety of applications that leverage electronic materials dueto the inherent tunability, porosity, and crystallinity associated with thesematerials. Hydrogen-bonded organic frameworks (HOFs) comprise an emergingclass of complementary porous materials that assemble crystalline networksmainly from intermolecular hydrogen-bonding interactions; however, relativelyfew reports on functional HOFs exist as these reversible interactions are muchweaker than the coordination or covalent bonds found in the former frameworks,which presents additional challenges in the isolation and activation of HOFs. Inthis work, we introduce an approach to access a permanently porous HOF derivedfrom a tetrathiafulvalene (TTF) core, which is thefirst HOF reported to date that exhibits electrical conductivity. Uponprecipitation from solution, HOF-110 self-assembles in a preferred orientation that contains vertical columns of TTF dimers,and the postsynthetic incorporation of iodine within the nanoporous channels of this framework affords pressed pelletconductivity values of up to 6.0x10-7Smiddotcm-1, which is an almost 30-fold improvement compared with pressed pellets of thepristine framework. Extensive structural characterization studies suggest the presence of radical mixed-valence TTF/TTFmiddot+species within these materials, which is consistent with previous reports on analogous TTF-based MOFs and COFs. Overall,this work presents a viable strategy to develop robust, electrically conductive frameworks built from purely intermolecularinteractions, further expanding the toolbox available for the assembly of functional porous materials.

Automated summary

Recent advancements in conductive metal-organic frameworks and covalent organic frameworks have led to increased interest in leveraging electronic materials due to their tunability, porosity, and crystallinity. Hydrogen-bonded organic frameworks are an emerging class of porous materials with weaker, reversible interactions, presenting challenges in isolation and activation. A novel approach using a tetrathiafulvalene (TTF) core has been developed to create a permanently porous HOF with electrical conductivity, showing promising results in structural characterization studies.