Phase dependent luminescent property of N,N-di(n-octyl)quinacridone crystals

• A polymorph and a pseudopolymorph of N,N-di(n-octyl)quinacridone (DOQA) are prepared.
• Two forms show different molecular packing structures.
• Different morphologies and luminescent properties of two forms are exhibited.
• DOQA was employed as building blocks to fabricate luminescent microscale wires.

A polymorph A and a pseudopolymorph B of N,N-di(n-octyl)quinacridone (DOQA) have been prepared by altering the crystal growth conditions and their molecular structures have been identified by single-crystal X-ray diffraction. Both polymorphs show similar characteristics of molecular structures and their molecular arrangements are characterized by the intermolecular π…π interactions and CH…O hydrogen interactions. Due to the presence of methanol molecules in the form B, it is found that in crystalline polymorphs A and B the distance and the degree of overlap of π-electron are remarkably different. Simultaneously, molecules of two forms show different hydrogen bonding patterns. The different molecular packing structures result in significantly different morphologies, namely block shape for A whereas needle shape for B, and solid-state luminescent properties of two forms. From the X-ray single-crystal analysis, the obvious different molecular packing structures of two forms, due to the presence of methanol molecules in the form B, urge us to investigate the phase-dependent emission properties of DOQA in microstructures. DOQA can be employed as building blocks to fabricate luminescent microscale wires by controlling the ratio of methanol solvent.

The crystallization of DOQA affords a polymorph A and a pseudopolymorph B. Both polymorphs show similar characteristics of molecular structures and their molecular arrangements are characterized by the intermolecular π…π interactions and CH…O hydrogen interactions. It is found that, due to the presence of methanol molecules in the form B, the distance and the degree of overlap of π-electron are remarkably different in crystalline polymorphs A and B. Simultaneously, molecules of two forms show different hydrogen bonding patterns. The different molecular packing structures result in significantly different emission properties and different morphologies of two polymorphs, namely, block shape for A whereas needle shape for B. From the X-ray single-crystal analysis, the obvious different molecular packing structures of two forms urge us to investigate the phase-dependent emission properties of DOQA in microstructures. DOQA can be employed as building blocks to fabricate luminescent microscale wires by controlling the ratio of methanol solvent.Figure optionsDownload high-quality image (48 K)Download as PowerPoint slide