An expanded hydrogen-bonded organic framework formed by a tetrakis(terphenyl)ethene derivative

Abstract

Abstract A low-density hydrogen-bonded organic framework (HOF) with channel aperture with dimensions of 33.8 Å × 55.2 Å was constructed from a tetrakis(terphenyl)ethene derivative. The structure was successfully characterized by single crystalline X-ray diffraction analysis. Although solvent molecules are included in the channel, the present framework is one of the HOFs with the largest aperture. The framework is based on H-bonded sql-networks that stack in an eclipse fashion. The interlayer interactions were thoroughly investigated on the basis of the crystal structure. Interestingly, thee analogues of tetraarylethene-based tetracarboxylic acids, including the title compounds, formed the same H-bonded sql-network as a lower-dimensional supramolecular motif. However, the motifs are assembled in completely different ways to give the corresponding three types of the framework, indicating the importance of precise design of the secondary interactions between the lower dimensional motifs. In solid state, the molecular unit of the constructed HOF shows a largely Stokes-shifted and strong emission due to a fast (< 15 ps) ICT and a relatively slower (90 ps) intermolecular PT reaction, while in DMF it exhibits a strong H-bond with the solvent.