Abstract: | The bromo‐ and iodoaza‐closo‐dodecaboranes HNB11H10Hal (Hal = Br, I), MeNB11H9Br2, and MeNB11H8Br3 are formed from NB11H11]– and MeNB11H11, respectively, by electrophilic halogenation with elementary halogen in the presence of acidic catalysts. Hydrogen in para‐ or in para‐ and meta‐position with respect to the cluster‐N atom is substituted by halogen. With iodine chloride as halogenation agent, all the 11 boron bound H atoms of MeNB11H11 are substituted to give HNB11Cl5I6 with iodine in the para‐ and meta‐ and chlorine in the ortho‐positions, presumably via electrophilic (I) and nucleophilic substitution (Cl). The products are characterized by their NMR spectra, the product HNB11Cl5I6 also by crystal structure analysis. |