Wide-Gap 1D-, 2D-, and 3D-Hydrogen-Bonded Organic Frameworks Hierarchically Weaved by Macrocyclic Supramolecular Multifluorine Tectons

Abstract

A series of 1D-, 2D-, and 3D-hydrogen-bonded organic frameworks (1D-, 2D-, and 3D-HOFs) force-driven by macrocyclic multifluorine tectons (F-tectons) was constructed on the basis of burgeoning multifluorinated diaminoterephthalates (25, 345, and 26). Crystalline 25 gave ladder-shaped 1D-HOFs containing one kind of macrocyclic F-tecton looped by two F···H­(CH3) hydrogen bonds in competition with strong π···π and π···H­(CH3) interactions. Crystalline 345 gave layer-by-layer translational 2D-HOFs containing hierarchically macrocyclic F-tectons looped by 8-fold hydrogen bonds, including three F···H­(CH3), three O···HN and two ArC···H­(CH3) prior to weak π···π interactions. Crystalline 26 possessed 2-fold interpenetrated 3D-HOFs containing hierarchically macrocyclic F-tectons looped by F···H­(CH3), ArH···F, and ArH···F···H­(CH3) hydrogen bonds and interpenatrated by strong π···π interactions. In addition to that, the electron-withdrawing multifluorination of diaminoterephthalates caused an optical blue shift with wide optical energy gaps (2.43–2.51 eV) for 25, 345, and 26 in solution and a wide optical band gap (2.31 eV) for 345 in the film state. The multifluorination effect confirms an interesting trend that more F atoms bring in deeper highest occupied molecular orbital (HOMO)/lowest unoccupied molecular orbital (LUMO) energy levels (345 vs 25/26) and also regioisomerism confirms that farther F atoms bring in deeper HOMO/LUMO energy levels (25 vs 26).

Recent Advances in Luminescent Hydrogen‐Bonded Organic Frameworks: Structures, Photophysical Properties, Applications

“…The phosphorescence quantum yields of PTOCz and MTOCz in HOF crystal are 0.33% and 0.057%, respectively. To improve phosphorescence efficiency of HOFs, an organic compound DCzPO (38) was designed as the building block of a HOF structure (Figure 14a,b). [54] The HOF with a lifetime of 398 ms demonstrated high phosphorescence efficiency of 3%.…”

“…The HOF structure quenched red fluorescent emission and generated intense emission after grinding. [37] Recently, a series of HOFs driven by macrocyclic multifluorine tectons (28-30) were reported by Chen et al [38] The lifetimes of HOFs were only several nanoseconds. 2D-HOF and 3D-HOF exhibited obvious aggregation-induced quenching (ACQ) characteristics.…”