Haloaza-closo-dodecaboranes

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.