Tridecacyclene: A Cyclic Tetramer of Acenaphthylene

Area of Science:

• Organic Chemistry
• Materials Science
• Supramolecular Chemistry

Background:

• Decacyclene, a cyclic trimer of acenaphthylene, is a well-known planar polycyclic aromatic hydrocarbon.
• The synthesis and properties of larger cyclic acenaphthylene derivatives remain largely unexplored.
• Understanding structure-property relationships in non-planar aromatic systems is crucial for developing new electronic materials.

Purpose of the Study:

• To report the single-step synthesis of a novel cyclic tetramer of acenaphthylene.
• To characterize the structural, electronic, and packing properties of this new material.
• To investigate the potential for forming supramolecular assemblies with fullerenes.

Main Methods:

• Lewis acid-catalyzed aldol cyclization of 1-acenaphthenone.
• Single-crystal X-ray diffraction for structural and packing analysis.
• Electrochemical measurements (reduction potential) and optical spectroscopy (optical gap).

Main Results:

• Successful single-step synthesis of a cyclic tetramer of acenaphthylene featuring a central eight-membered ring.
• The molecule exhibits significant non-planarity, leading to a decreased reduction potential (-0.4 eV) and optical gap (-0.73 eV) compared to decacyclene.
• Unique crystal packing with substantial π-stacking and formation of shape-complementary cocrystalline supramolecular assemblies with buckminsterfullerene.

Conclusions:

• The synthesized cyclic tetramer is a novel material with distinct structural and electronic properties due to its non-planar, saddle-like shape.
• The unique shape facilitates the formation of ordered supramolecular structures with fullerenes.
• This work expands the family of cyclic acenaphthylene derivatives and highlights their potential in materials science.