Cu─X Bonds Regulated Conduction and Polarization Loss in Conductive Metal-Organic Framework Under Electromagnetic Field

Conduction and polarization are known to profoundly impact conductive metal-organic frameworks (c-MOFs) for their applications in electromagnetic wave (EMW) absorption. Albeit a few advances along c-MOF platforms in enhancing their EMW absorption performances, reticular modulation-led inter/intra-layer conduction and polarization loss remains an unmet challenge. To address this, a ligand substitution-guided bottom-up structural control strategy is introduced to study the depth of reticular modulation-led inter/intra-layer conduction and polarization loss in c-MOFs under an electromagnetic (EM) field. A family of triphenylene-X ligands (X = -NH 2, -OH, and -SH) is harnessed to afford an isoreticular family of three Cu-based c-MOFs. Thanks to the distinct Cu─X bonds, such a platform allowed to systematically study the synergistic features of conduction and polarization loss in EMW absorption enhancement. One of the trio, Cu 3(HITP) 2 (X = -NH 2; HITP, 2,3,6,7,10,11-hexahydroxytriphenylene) is identified with an optimal EM loss capacity under the EM field, achieving a record-high reflection loss of -63.03 dB in the effective absorption range of 3-18 GHz band. Setting up a new benchmark for EM loss among c-MOFs, this study introduces a way to leverage control in the charge mobility characteristics of Cu─X bonds relative to the dielectric losses at both molecular and atomic scales.