Organic and Inorganic Chemistry of Iodine Oxides

Abstract

IN comparing multivalent iodine with multi-valent nitrogen, I was led in 1933 to try the action of iodic acid upon aromatic compounds; an unexpected result was found, namely, the copious formation of iodonium salts. The existing knowledge of these proving to be inadequate, a long digression was necessary in which we were able to clear up the main chemistry of iodoxy-compounds and to discover (inter alia) that iodine can form compounds in which it recalls quinquevalent arsenic as this is seen in arsinic and arsonic acids; some of the ways in which iodonium salts are derived from iodoxy-and iodoso-compounds were elucidated¹. Mr. Race and I then reverted to the initial reaction, which takes place in sulphuric acid media of hydration less than H₂SO₄.H₂O; from iodic acid and chlorobenzene, for example, one obtains in a single operation an 80 per cent yield of the para-iodonium derivative. Benzene similarly yields diphenyl-iodonium salts, and its derivatives with o-p-directing substituents (provided that these are not too highly activating) react in the same way; while meta-directing substituents like the nitro-group prevent the reaction. Particulars of this work will be published.