Deoxycholamide Crystalline Frameworks as a Platform of Highly-Efficient Fluorescence Materials

To achieve spatially oriented molecular arrays with a wide range of dye molecules, an organic lattice framework is a promising platform, because its flexible superstructure connected by labile hydrogen bonds can tune the host framework to provide the dyes geometrically oriented in the appropriate inclusion spaces. In this Article, we demonstrate that inclusion crystalline lattice composed of deoxycholamide (DCM) can be applied as a platform to arrange various “skinny” dye molecules such as anthracene and 1,6-diphenylhexatriene into a tandemly aligned array without π/π stacking interactions in the inclusion channel. As compared to its parent compound deoxycholic acid (DCA), DCM forms additional N–H···O interactions between DCM molecules, stabilizing the host framework. The density of the guest dyes included in the DCM channels can be controlled upon changing crystallization solvent: nonpolar solvents give inclusion crystals (ICs) containing a small amount of dye molecules (I-state), while polar ones give ICs whose channels are filled by tandemly arrayed dyes (F-state). ICs of dyes, even in the densely packed F-sate, exhibit fluorescence quantum yields higher than the naked dye crystals and comparable to the diluted solutions.