Do Corroles Stabilize Tetravalent Antimony?

Antimony corrole cations have been prepared by one-electron oxidation of antimony(III) congeners with silver(I) and copper(II) salts. Isolation and crystallization was successful for the first time, and the X-ray crystallographic investigation unraveled structural similarities with antimony(III)corroles. EPR experiments showed strong hyperfine interactions of the unpaired electron with the ¹²¹ Sb (I=5/2) and ¹²³ Sb nuclei (I=7/2). A DFT analysis supports the description of the oxidized form as a Sb^III corrole radical with less than 2 % Sb^IV character. In the presence of water or a fluoride source like PF₆ ^- , the compounds undergo a redox disproportionation to yield known antimony(III)corroles and either difluorido-antimony(V)corroles, or bis-μ-oxido-di[antimony(V)corroles] via novel cationic hydroxo-antimony(V) derivatives.