Two-dimensional Porous Framework Assembled through Hydrogen-bonds and Dipole-dipole Interactions

Slip-Stacking of Benzothiadiazole Can Provide a Robust Structural Motif for Porous Hydrogen-Bonded Organic Frameworks

“…Electron-withdrawing nature of BT makes it a useful building block of organic electronic devices. − Meanwhile, large dipole moment (4.8 Debye) of BT also plays an important role from supramolecular point of view. Namely, introduction of BT moieties in frameworks can enhance intermolecular interactions through dipole–dipole or dipole–quadruple interactions. − Indeed, we previously revealed that a tetracarboxylic acid possessing a BT moiety, 5,5′-(benzo­[ c ]­[1,2,5]­thiadiazole-4,7-diyl)­diisophthalic acid ( BTIA ), gave a layered HOF BTIA-1 , in which BT moieties are slip-stacked unidirectionally to regulate lamination manner of 2D honeycomb sheets . Based on this finding, we subsequently planned to construct an isostructural HOF with larger pores based on an expanded BT derivative, BTTA (Figure ).…”

“…38−40 Indeed, we previously revealed that a tetracarboxylic acid possessing a BT moiety, 5,5′-(benzo[c][1,2,5]thiadiazole-4,7-diyl)diisophthalic acid (BTIA), gave a layered HOF BTIA-1, in which BT moieties are slip-stacked unidirectionally to regulate lamination manner of 2D honeycomb sheets. 29 Based on this finding, we subsequently planned to construct an isostructural HOF with larger pores based on an expanded BT derivative, BTTA (Figure 1).…”

“…It is noteworthy that the present noncentrosymmetric molecular arrangement of BTTA-1(TCB) is closely similar with that of BTIA-1(TCB), which is estimated by the crystal structure prediction technique. 29 In more details, although space group of the predicted structure of BTIA-1(TCB), that is, P1, is different from that of BTTA-1(TCB), that is, Cm, this discrepancy originates from software limitation. Even the molecular conformation of BTIA applied for the calculation has a Cs symmetry; this was not recognized in the calculation, and therefore, the resultant crystal belongs to space group P1.…”

“…We also activated BTIA-1 by the solvent exchange methodology, affording BTIA-1a with better crystallinity than that reported before. 29 Activated HOFs BTTA-1a and BTIA-1a prepared by the solvent exchange were subjected to gas sorption experiments. A N 2 sorption isotherm recorded at 77 K shows rapid rise at low pressures and continuous increase up to relative pressure of P e /P 0 = 1.0.…”

“…In connection with this, we have proposed that unidirectionally aligned slip-stacking of benzo­[ c ]­[1,2,5]­thiadiazole (BT) can be applied as an additional supramolecular synthon to construct a stable 2D HOF . Electron-withdrawing nature of BT makes it a useful building block of organic electronic devices. − Meanwhile, large dipole moment (4.8 Debye) of BT also plays an important role from supramolecular point of view.…”