Electrically Conductive π-Intercalated Graphitic Metal-Organic Framework Containing Alternate π-Donor/Acceptor Stacks

Two-dimensional graphitic metal-organic frameworks (GMOF) often display impressive electrical conductivity chiefly due to efficient through-bond in-plane charge transport, however, less efficient out-of-plane conduction across the stacked layers creates large disparity between two orthogonal conduction pathways and dampens their bulk conductivity. To address this issue and engineer higher bulk conductivity in 2D GMOFs, we have constructed via an elegant bottom-up method the first π-intercalated GMOF (iGMOF1) featuring built-in alternate π-donor/acceptor (π-D/A) stacks of Cu^II -coordinated electron-rich hexaaminotriphenylene (HATP) ligands and non-coordinatively intercalated π-acidic hexacyano-triphenylene (HCTP) molecules, which facilitated out-of-plane charge transport while the hexagonal Cu₃ (HATP)₂ scaffold maintained in-plane conduction. As a result, iGMOF1 attained an order of magnitude higher bulk electrical conductivity and much smaller activation energy than Cu₃ (HATP)₂ (σ=25 vs. 2 S m^-1 , E_a =36 vs. 65 meV), demostrating that simultaneous in-plane (through-bond) and out-of-plane (through πD/A stacks) charge transport can generate higher electrical conductivity in novel iGMOFs.