Transition Behaviors of Isostructural sql-Topological Hydrogen-Bonded Frameworks Composed of Naphthalene, Quinoxaline, and Pyrazinopyrazine Derivatives

A series of isostructural reticular framework materials with systematic differences on chemical structures allows us to disclose correlations between specific structural factors and properties, providing insights for designing novel porous frameworks. However, even slight differences in the molecular structure often lead to non-isostructural polymorphic frameworks particularly in the case of hydrogen-bonded organic frameworks (HOFs) because the structures of HOFs are based on a subtle balance of reversible interactions. In this study, we found that three simple analogues of tetracarboxylic acids with naphthalene, quinoxaline, and pyrazinopyrazine cores (NT, QX, and PP, respectively) yield isostructural solvated HOFs (NT-1, QX-1, and PP-1, respectively), where hydrogen-bonded sql-networked sheets are slip-stacked with closely similar manners, and that these HOFs undergo structural transformations in different ways by guest solvent removal. Comparison of the crystal structures of the HOFs before and after the transformation revealed that intermolecular interactions of the core significantly affected on rearrangements of hydrogen bonds after the transformation. The results suggest the potential to control the properties and functions of isostructural HOFs by elemental doping.