Haloaza-closo-dodecaboranes

The bromo- and iodoaza-closo-dodecaboranes HNB(11)H(10)Hal (Hal = Br, I). M eNB11H9Br2, and McNB(11)H(8)Br(3) are formed from [NB11H11](-) and MeNB11H1 1, respectively, by electrophilic halogenation with elementary halogen in t he presence of acidic catalysts. Hydrogen in para- or in para- and meta-pos ition with respect to the cluster-N atom is substituted by halogen. With io dine chloride as halogenation agent, all the 11 boron bound H atoms of MeNB 11H11 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 NM R spectra, the product HNB11Cl5I6 also by crystal structure analysis.