快猫短视频

A RAGING lion of the chemical world has been tamed. Japanese chemists have made the first moderately stable 鈥渢riplet carbene鈥�, a type of free radical that鈥檚 normally extremely reactive and short-lived. The carbene lives for nearly half an hour and could pave the way to new carbon-based, organic magnets.

Carbon usually forms four covalent bonds with other atoms by sharing four of its electrons with them. Many reactions involve breaking one or more of these bonds, leaving an 鈥渁ngry鈥� intermediate molecule with unpaired electrons. This normally reacts instantly to form a new compound.

In 1900, the chemist Moses Gomberg produced a fairly stable carbon intermediate with one unpaired electron. Now, a century later, Hideo Tomioka of Mie University in Tsu and his team have made a long-lived intermediate with two unpaired electrons-a triplet carbene. They did this by using light to chop nitrogen off a carefully designed organic molecule related to diazomethane (see Diagram). The carbene had a half-life of 19 minutes at room temperature. Tomioka says he had no idea the plan would be so successful. 鈥淪ome people may call it serendipity,鈥� he says.

If scientists can make carbenes stable indefinitely, they could be used to make mini magnets, thanks to the spin of the two unpaired electrons. Organic magnets are lighter and more flexible than their metal cousins, and can even be made transparent or insulating (快猫短视频, 8 November 1997, p 42). They鈥檙e tipped to play a key role in data storage, optical displays and optical computers.