Scientists Develop Sunlight Method to Break Tough Carbon–Fluorine Bonds

Fluorinated organic molecules are widely used across pharmaceuticals, agrochemicals, polymers, and industrial processes due to their stability.

In a major scientific advancement, researchers have developed an environmentally friendly, sunlight-powered method to break one of the strongest chemical bonds known — the carbon–fluorine (C–F) bond. This breakthrough holds immense potential for recycling fluorinated materials, designing new drugs, and transforming industrial chemicals that rely heavily on fluorinated compounds.

Fluorinated organic molecules are widely used across pharmaceuticals, agrochemicals, polymers, and industrial processes due to their stability. However, this very stability makes them difficult to modify or degrade. The exceptional strength of the C–F bond has traditionally required harsh reaction conditions, costly metal catalysts, and energy-intensive methods, often leaving sustainable processing out of reach.

COFs: A New Frontier in Green Photocatalysis

Researchers from the S. N. Bose National Centre for Basic Sciences, an autonomous institute under India’s Department of Science and Technology (DST), have introduced a pioneering solution through covalent organic frameworks (COFs). These crystalline, porous materials are known for their structural robustness, tunable properties, and high surface area — characteristics that make them ideal candidates for catalytic applications.

The team engineered a modified form of a bipyridine-based COF (Tp-Bpy). By introducing a methyl group through a simple post-synthetic methylation step, they produced a positively charged version, Tp-Bpy-Me COF. Despite this structural tweak being minimal, it significantly enhanced the COF’s electron-deficient nature and ability to absorb visible light efficiently.

Breaking C–F Bonds Using Blue Light and Sunlight

The newly developed cationic COF demonstrated remarkable photocatalytic efficiency. Under blue light irradiation, it successfully activated the strong C–F bond and enabled the formation of C–N bonds through nucleophilic attack by amines — a crucial step in synthesizing complex organic molecules.

Even more impressively, the reaction proceeded under natural sunlight, making this method a truly green and energy-efficient alternative to traditional catalytic systems. This represents the first demonstration of a COF-based photocatalyst converting C–F bonds into C–N bonds, opening the door to sustainable chemical transformations.

Broad Applications Across Industries

The aminated products obtained through this reaction pathway have significant potential applications, including:

• Pharmaceuticals – for synthesizing drug intermediates

• Agrochemicals – for designing more efficient crop protection agents

• Green chemistry – enabling degradable pathways for persistent fluorinated pollutants

• Natural product synthesis – as key molecular building blocks

This work not only showcases the power of COFs as next-generation photocatalysts but also highlights a scalable path toward eco-friendly chemical manufacturing, leveraging the most abundant renewable resource available — sunlight.

For the full research article, refer to: https://doi.org/10.1002/anie.202516235