Merging One- and Multi-Photon Processes in Hydrogen-Bonded Organic Frameworks for Enhanced NIR Light-Driven Photothermal and Photochemical Conversions.

Abstract

Direct application of near-infrared (NIR) light for solar-thermal and solar-chemical conversions is of emergent interest to improving efficiency in solar-energy utilization. Herein, we report a synthetic approach to NIR-responsive materials by self-assembly of hydrogen-bonded organic frameworks (HOF-1/2/3) from multifunctionalized Ru-components incorporating chiral, photoactive, H-bonding, π-stacking, and protonation/deprotonation subunits. Significantly, protonation of the imidazole-subunits in HOF-3 promotes densified packing to extend NIR-absorption tail up to 1100 nm with a narrowed bandgap of 1.41 eV, meanwhile leads to spontaneous resolution of enantiomeric Δ-/Λ-HOF-3. Consequently, remarkably enhanced photothermal effect and photocatalytic performance, including chiroptical activity induced by circularly polarized NIR-light, are achieved through synergy of direct one- and multi-photon NIR-absorption, underscoring effectiveness to bring multifunctionalities into ordered HOFs for generation of robust and effective materials with multimode NIR-responsiveness.