Reviewed by Lexie CornerMar 19 2025
Researchers at the University of Vienna's Institute of Organic Chemistry have developed a new method for creating azaparacyclophanes (APCs), a family of complex ring-shaped molecules with significant potential in material science. The newly developed Catalyst-Transfer Macrocyclization (CTM) process simplifies the synthesis of these intricate macrocycles.
This innovation enables more efficient and scalable applications in supramolecular chemistry, organic electronics, and optoelectronics. These include potential uses in transistors, flexible solar cells, and displays.
Compared to typical flat panels of solar cells made of energy-intensive processed silicon, organic solar cells are lightweight, and hence can be used off-grid in unconventional surfaces. Image Credit: University of Vienna
APCs are small molecular rings with repeating units connected in a continuous loop. These macrocyclic organic compounds have a unique structure, making them important for advanced technologies, including optoelectronic applications like display systems.
Traditionally, synthesizing APCs has been complex and labor-intensive, requiring multiple steps under challenging conditions.
A Shortcut to Complex Molecular Rings
The "Pd-catalyzed Buchwald-Hartwig cross-coupling reaction" is used in the newly developed CTM technique to form carbon-nitrogen bonds, producing π-conjugated cyclic structures. The term "π-conjugated" refers to a pattern of alternating single and double bonds, which enhances the material's electrical properties by allowing free electron mobility. The CTM technique simplifies the creation of APCs through its direct and efficient approach.
With this approach, we can create structurally precise APCs in a short time, under mild conditions and with high yields, making them much more accessible for both research and industrial applications.
Josue Ayuso-Carrillo, Study First Author, University of Vienna
The method is versatile, allowing the production of APCs with various functional groups and ring sizes (typically 4–9 members). Unlike traditional macrocyclization methods that require highly diluted conditions, the CTM technique can be carried out under normal concentrations (35–350 mM), making it scalable and reproducible.
A Game Changer for Advanced Technologies
The process produces APCs with significant potential for solar technology and organic semiconductors. Due to their π-conjugated structures, APCs promote effective electron flow, making them valuable in various applications. They can improve the flexibility and efficiency of solar cells, transistors, and displays in organic electronics.
Organic electronics, such as flexible solar cells, use organic materials. They are lighter than conventional silicon-based panels and can be used off the grid on unconventional surfaces, as they do not rely on energy-intensive processed silicon.
The properties of APCs also enhance light-harvesting systems, improving solar energy conversion and storage. Additionally, APCs can be applied in supramolecular chemistry to create advanced molecular recognition systems, sensors, and catalysts.
The CTM method is not only a breakthrough in synthesis, but also a stepping stone towards the large-scale production of tailor-made materials. By eliminating unnecessary complexity, we open the door to new functional applications that were previously out of reach. And, importantly, we demonstrate the reproducibility of our method by providing a step-by-step guide for researchers in related fields.
Davide Bonifazi, Study Senior Author, University of Vienna
From the Lab to Industry
The CTM process simplifies the synthesis of high-performance organic components, enhancing their applicability in industrial settings. Its scalability ensures a smoother transition from laboratory discoveries to practical use. This study marks a notable step forward in integrating advanced chemical synthesis into widely used technologies. Innovations like this are expected to shape the future of materials research, as industries continue to demand high-performance, sustainable materials.
Journal Reference:
Ayuso-Carrillo, J and Bonifazi, D., (2025) Catalyst-Transfer Macrocyclization Protocol: Synthesis of π-Conjugated Azaparacyclophanes Made Easy. JACS Au. doi.org/10.1021/jacsau.5c00109