Design and Construction of Isoreticular Hydrogen-Bonded Organic Frameworks
摘要
Successful construction of a series of isoreticular or isostructural porous frameworks allows systematic study on selective adsorption of molecules, catalytic reactions, and optical and electronical functionalities of the framework materials. Contrary to metal–organic frameworks (MOFs) and covalent organic frameworks (COFs), it is still challenging to construct controlled frameworks using noncovalent intermolecular interactions. Therefore, it seems to be a touchstone for noncovalent interaction-based reticular chemistry to construct such isoreticular frameworks. This chapter overviews isoreticular hydrogen-bonded organic frameworks (HOFs) developed in the author’s research group. The directional hydrogen bonding nature of carboxylic acids is significantly useful to preorganize building block molecules to a certain network structure. For example, hexatopic- and tetratopic-carboxylic acids tend to give predictable hxl- and sql-topological H-bonded network. However, even though the H-bonded network was formed as designed, the assembly manner of the network cannot be controlled without further robust interactions in addition to H-bonds. To accomplish isostructural assembly of the low network structures, a certain robust interaction that can work orthogonally to the hydrogen bonds is required. Herein, shape-fitted docking between the twisted π-conjugated molecules is proposed to build a series of robust isoreticular/isostructural frameworks. The effective shape-fitted docking was demonstrated in two systems: hexaazatripheneylene (HAT)- and dibenzo[g,p]chrysene (DBC)-based HOFs.