Expect the unexpected: why the chemistry community should pay more attention to ‘inert’ materials

At the end of last year, a Japanese team discovered that there was more than meets the eye to a mechanochemical cross-coupling reactions catalysed by nickel salts. The paper revealed that abrasion of stainless steel during ball milling activated nickel catalysts – without the need for mechanoredox catalysts, piezoelectric materials or common reductants – challenging the assumption that the materials used for ball-milling, such as stainless steel and zirconia, are inert.

‘In nickel catalysed C–N cross coupling, you usually need a reductant,’ explains Julia Khusnutdinova, a coordination and catalysis chemist at Okinawa Institute of Science and Technology in Japan, who led the research team. ‘I started discussing with my student what could be the reductant – he proposed some crazy ideas, like it could be hydroxyl radicals and I said: “No, no, you have stainless steel – it could just be stainless steel”.’