Orange crystal compound designed to include long but strong carbon bonds

This compound was designed to include long but strong ties between carbon atoms. Credit: Yusuke Ishigaki

Organic chemistry

Fundamental carbon bonds stretched to record-setting lengths

A fundamental link between atoms is pushed beyond the breaking point.

Chemists have set a record for the longest carbon–carbon bond ever measured in an electrically neutral molecule.

Single bonds between carbon atoms are the fundamental connection in genes, drugs and proteins. In all of these molecules, the length of the carbon–carbon bond is nearly constant. To probe the bond’s properties, chemists in the past have tried lengthening it, only to have the bond split.

Takanori Suzuki, Yusuke Ishigaki and their colleagues at Hokkaido University in Sapporo, Japan, sought to design a molecule containing a long, but robust, bond. They built a rigid hydrocarbon structure that shored up the bond. The researchers then added bulky hydrocarbons to the bonded carbons to push the atoms away from each other.

The stretched bond measured 1.806 ångströms — 1.17 times longer than normal.

Correction: an earlier version of this story listed Takuya Shimajiri rather than Yusuke Ishigaki as a corresponding author.