Stable GaX2, InX2 and TlX2 radicals

• Published in: Nature chemistry Vol. 6; no. 4; pp. 315 - 319
• Main Authors: Protchenko, Andrey V., Dange, Deepak, Harmer, Jeffrey R., Tang, Christina Y., Schwarz, Andrew D., Kelly, Michael J., Phillips, Nicholas, Tirfoin, Remi, Birjkumar, Krishna Hassomal, Jones, Cameron, Kaltsoyannis, Nikolas, Mountford, Philip, Aldridge, Simon
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01-04-2014; Nature Publishing Group
• Subjects: 639/638/263/910; 639/638/263/914; Analytical Chemistry; Biochemistry; Chemistry; Chemistry/Food Science; Crystallography; Gallium; Indium; Inorganic Chemistry; Laboratories; Metals; Organic Chemistry; Oxidation; Physical Chemistry; Resonance; Thallium; United Kingdom > UK; Australia
• ISSN: 1755-4330; 1755-4349
• DOI: 10.1038/nchem.1870

The chemistry of the Group 13 metals is dominated by the +1 and +3 oxidation states, and simple monomeric M
(II)
species are typically short-lived, highly reactive species. Here we report the first thermally robust monomeric MX
2
radicals of gallium, indium and thallium. By making use of sterically demanding boryl substituents, compounds of the type M(
II
)(boryl)
2
(M = Ga, In, Tl) can be synthesized. These decompose above 130 °C and are amenable to structural characterization in the solid state by X-ray crystallography. Electron paramagnetic resonance and computational studies reveal a dominant metal-centred character for all three radicals (>70% spin density at the metal). M
(II)
species have been invoked as key short-lived intermediates in well-known electron-transfer processes; consistently, the chemical behaviour of these novel isolated species reveals facile one-electron shuttling processes at the metal centre.
The chemistry of group 13 metals (M) is dominated by +1 and +3 oxidation states, so MX
2
species are typically metal–metal-bonded dimers, M(
II
)
2
X
4
or mixed-valence species M(
I
)M(
III
)X
4
. Now, monomeric M(
II
)(boryl)
2
radicals have been prepared for gallium, indium and thallium. The compounds — structurally characterized by X-ray crystallography — are stable up to 130 °C and exhibit dominant metal-centred radical character.