Intercalated conductive Metal-Organic frameworks constructed via Donor-Acceptor interactions for Ultratrace gas sensing

Two-dimensional conductive metal–organic frameworks (2D cMOFs) offer significant potential for gas sensing due to their tunable porosity and conductivity. However, their intrinsic anisotropic conductivity and limited accessible active sites hinder efficient three-dimensional charge transfer and selective analyte recognition. To address this challenge, this study presents a bottom-up strategy to construct intercalated conductive 2D cMOFs. The approach leverages supramolecular interactions between 2,3,6,7,10,11-hexahydroxytriphenylene (HHTP, donor) and 1,4,5,8,9,11-hexaazatriphenylenehexacarbonitrile (HATCN, acceptor) to preassemble ordered and alternating π-donor/acceptor (π-D/A) stacks, followed by coordination of HHTP linkers within the π-D/A stacks with square-planar Cu²⁺ ions. The resulting intercalated Cu₃(HHTP)₂/HATCN framework exhibits efficient charge transport both in-plane through delocalized π-orbital networks and out-of-plane via vertically aligned pathways facilitated by strong donor–acceptor stacking. Intriguingly, the Cu₃(HHTP)₂/HATCN-based sensors demonstrated sensitive and selective H₂S detection at room temperature, with a limit of detection of 120 ppb, which is outstanding compared to previously reported H₂S sensors. The sensing behavior can be correlated with the specific D-A electronic environment within the Cu₃(HHTP)₂/HATCN and tailored host–guest interactions, offering novel insights into the design of multifunctional MOF-based sensors with high sensitivity and selectivity.