Research Highlight

Metal-free catalyst for making drugs, smart materials

doi:10.1038/nindia.2018.92 Published online 25 July 2018

Like a chameleon changes colours, a phenalenyl based cation can change its property to regulate metal free C-H arylation catalysis.

© Mandal, S. et al.

Researchers have synthesised an organic molecule that can act as a metal-free catalyst in different pharmaceutical and chemical industries for making drugs and various smart molecules1.

To run chemical reactions, industries rely heavily on metal-based catalysts such as palladium. Besides being expensive and rare, they are toxic and difficult to remove from desired products such as drugs.

In search of a cheap and non-toxic catalyst, scientists from the Indian Institute of Science Education and Research in Kolkata, led by Swadhin K Mandal, prepared a phenalenyl-based molecule — an organic molecule-based metal-free catalyst. They then tested this molecule’s efficiency to catalyse arylation, an organic reaction widely used to make drugs and various natural products.  

They found that the organic catalyst catalysed the chemical reaction in the same way as transition metals such as palladium. Like palladium, the catalyst can accept electrons, store it and then deliver.  

The organic catalyst helped synthesie boscalid, an important agrochemical used to kill disease-causing fungi that destroy crops. This suggests that this organic catalyst can replace typical transition metals such as palladium, which are expensive and rare.

Besides, the catalyst can set off chemical reactions even in the absence of light.

The organic catalyst, set to replace expensive metal-based catalysis at room temperature, can even help make smart materials such as organic light-emitting diode, says Mandal. 


1. Ahmed, J. et al. Integrating organic Lewis acid and redox catalysis: the phenalenyl cation in dual role. J. Am. Chem. Soc. (2018) doi: 10.1021/jacs.8b04786