Photobromination of Halogenobenzenes: Ipso-Attack or Not?

In a preliminary communication (2) we reported the results obtained in the photo- and ionic brominations of halogeno- and dihalogenobenzenes. A recent paper(3) suggested that our results “are suggestive of ipso-attack, a mechanism that has not previously been advocated for free-radical reactions”. The purpose of this communication is to point out that the proofs of such a mechanism are not borne out by our data. This does not imply that ipso-attack has to be rejected but it needs other data to be proved and remains only a simple although attractive hypothesis.