It’s make or break
They have used the complex to study how much energy is required to make or break the bond – consisting of two electrons – between the tin and the cobalt, which will provide useful information for designing new molecules in the future.
They have also shown that each half of the complex – the cobalt–ligand complex and the tin–ligand complex – can exist in a stable state on their own. These separated complexes are what’s known as 'radicals' – that is they each get to take away one electron from the two-electron bond between them. Tin radicals in particular are relatively rare, and this particular one – featuring a four-coordinate ligand – has never been observed before.
Unique structure and reactivity
"This is the first room-temperature observation of a four-coordinate tin radical, which is not only unique in structure but also comes with a unique reactivity not shared by the conventional three-coordinate tin radicals", says Dr Fu.
The new complex is not just interesting to fundamental chemists. It changes colour from blackish yellow to red upon exposure to light and oxygen, meaning that it could be used to detect changes in the environment in, for example, food packages.
This article is free to read in our open access, flagship journal Chemical Science: Zikuan Wang et al., Chem. Sci., 2018, Advance Article. DOI: 10.1039/C8SC01269E