title: Highly Chlorinated, Brominated, and Iodinated Icosahedral Carborane Anions: 1-H-CB(11)X(11)(-), 1-CH(3)-CB(11)X(11)(-) (X = Cl, Br, I); 1-Br-CB(11)Br(11)(-).
abstract: Direct chlorination of 1-CH(3)-CB(11)H(11)(-) in glacial acetic acid gave the highly chlorinated carborane anion 1-CH(3)-CB(11)Cl(11)(-), and treatment of 1-CH(3)-CB(11)H(11)(-) with ICl in triflic acid afforded the highly iodinated carborane anion 1-CH(3)-CB(11)I(11)(-). Under similar or more vigorous reaction conditions, however, the reaction of 1-CH(3)-CB(11)H(11)(-) with Br(2) in triflic acid did not proceed to completion. The highly brominated carborane anion 1-CH(3)-CB(11)Br(11)(-) was achieved via a sealed-tube reaction. This new method has led to the isolation of 1-H-CB(11)X(11)(-) (X = Cl, Br, I) and 1-Br-CB(11)Br(11)(-) in high yield. The lithiation of 1-H-CB(11)X(11)(-) resembles that of its parent anion CB(11)H(12)(-). Treatment of these lithio species with methyl iodide gave the methylated carborane anions 1-CH(3)-CB(11)X(11)(-). These new weakly coordinating anions were fully characterized by (1)H, (13)C, and (11)B NMR, IR, and negative-ion MALDI MS spectroscopy. Some were further confirmed by single-crystal X-ray analysis.
authors.affiliation: Department of Chemistry, The Chinese University of Hong Kong, Shatin NT, Hong Kong, China.
authors.forename: Zuowei
authors.initials: Z
authors.lastname: Xie
authors.forename: Chi-Wing
authors.initials: CW
authors.lastname: Tsang
authors.forename: Eric Tung-Po
authors.initials: ET
authors.lastname: Sze
authors.forename: Qingchuan
authors.initials: Q
authors.lastname: Yang
authors.forename: Dominic T. W.
authors.initials: DT
authors.lastname: Chan
authors.forename: Thomas C. W.
authors.initials: TC
authors.lastname: Mak