A new light-powered chemical technique could give scientists more freedom to design drug molecules with complex three-dimensional shapes. Researchers at the University of Hong Kong (HKU) have developed a way to produce molecular structures that could serve as alternatives to benzene rings, which are widely used in medicines but can sometimes limit their properties.

Led by Professor Jian He from HKU’s Department of Chemistry, the team developed specialized copper(I) photosensitizers that use visible light to construct bicyclo[2.1.1]hexanes, or BCHs. Published in Nature Chemistry, the research addresses two major challenges in producing these structures: the limited range of compatible starting materials and unwanted chemical reactions that interfere with synthesis.