Linker Aromaticity Reduces Band Dispersion in 2D Conductive Metal–Organic Frameworks
Monique C. Demuth, Christopher H. Hendon
Abstract
All 2D electrically conductive metal–organic frameworks (MOFs) are constructed from hexasubstituted aromatics that oxidize during self-assembly. Since electrical conduction is thought to occur through the ligand π-system, but aromaticity itself results in stabilized π-electrons, the delocalization of ligand wavefunctions should be inversely related to the ligand π-stability. That is, aromatic π-electrons should prefer to localize on a single linker rather than delocalize to form a curved band in the MOF. Here, we use a combination of NICS-xy scans and bulk electronic band structure calculations to show that the extent of residual aromaticity in the oxidized linker is a good predictor for electronic localization in the resultant MOF. Thus, ligands that feature antiaromatic π-systems in the oxidation state found within the MOF should yield increased band curvature, a target parameter that affects charge mobility in high performing electrical conductors.