title: Synthesis and structural characterization of highly chlorinated, brominated, iodinated, and methylated carborane anions, 1-H-CB9X9-, 1-NH2-CB9X9- (X = Cl, Br, I), and 1-H-CB9(CH3)9-.
abstract: The highly chlorinated, brominated, and iodinated carborane anions 1-R-CB9X9- (R = H, NH2; X = Cl, Br, I) were prepared in high yields by treatment of [Me3NH][1-R-CB9H9] with excess ICl, Br2/triflic acid, and I2/triflic acid, respectively, in sealed tubes at 180-240 degrees C. With the aid of a Pd catalyst, B-I bonds could be converted into the B-Me bonds by treatment with excess MeMgBr, which led to the preparation of the permethylated species 1-H-CB9Me9- in good yield. These new anions were fully characterized by 1H, 13C, and 11B NMR, IR, and negative-ion MALDI MS spectroscopy. Some were further characterized by single-crystal X-ray analyses. The weakly coordinating nature of these new anions was probed by 29Si chemical shifts.
authors.affiliation: Department of Chemistry, Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China.
authors.forename: C W
authors.initials: CW
authors.lastname: Tsang
authors.forename: Q
authors.initials: Q
authors.lastname: Yang
authors.forename: E T
authors.initials: ET
authors.lastname: Sze
authors.forename: T C
authors.initials: TC
authors.lastname: Mak
authors.forename: D T
authors.initials: DT
authors.lastname: Chan
authors.forename: Z
authors.initials: Z
authors.lastname: Xie