Incremental iodination of the eight-vertex closo monocarborane anion [closo-1-CB7H8](-): preparation and characterization of [closo-1-CB7H5-6,7,8-I-3](-) and [closo-1-CB7H2-2,3,4,6,7,8-I-6](-), and the synthesis of the first eight-vertex C-methylated carborane anion [1-CH3-closo-1-CB7H4-6,7,8-I-3](-)

0356979 - ÚACH 2011 RIV CZ eng J - Journal Article
Dostál, Radim - Londesborough, Michael Geoffrey Stephen - Kvíčalová, Magdalena - Macháček, Jan - Císařová, I. - Janoušek, Zbyněk
Incremental iodination of the eight-vertex closo monocarborane anion [closo-1-CB7H8](-): preparation and characterization of [closo-1-CB7H5-6,7,8-I-3](-) and [closo-1-CB7H2-2,3,4,6,7,8-I-6](-), and the synthesis of the first eight-vertex C-methylated carborane anion [1-CH3-closo-1-CB7H4-6,7,8-I-3](-).
Collection of Czechoslovak Chemical Communications. Roč. 75, č. 9 (2010), s. 931-947. ISSN 0010-0765
R&D Projects: GA MŠMT LC523; GA MŠMT ME09114
Institutional research plan: CEZ:AV0Z40320502
Keywords : carboranes * monocarborane anions * eight-vertex
Subject RIV: CA - Inorganic Chemistry
Impact factor: 0.853, year: 2010

Iodination of [closo-1-CB7H8](-) (anion 1) with elemental iodine under various controlled conditions yields a continuum from mono-to hexaiodinated derivatives including the previously unknown [closo-1-CB7H5-6,7,8-I-3](-) (anion 5) and [closo-1-CB7H2-2,3,4,6,7,8-I-6](-) (anion 8). These species, characterized by mass spectrometry and NMR spectroscopy, and, in the case of 8, by single-crystal X-ray diffraction, provide insight into the fluxional molecular behavior of anion 1 in solution. Investigation of direct electrophilic substitution on the carbon-vertex of anion 1 using standard conditions and reagents (deprotonation by BuLi followed by addition of electrophile) proved futile, but the same conditions when using the new triiodo-deravitive anion 5 resulted in the formation of the first eight-vertex C-methylated carborane anion [1-CH3-closo-1-CB7H4-6,7,8-I-3](-) (anion 9), in 60% yield.
Permanent Link: http://hdl.handle.net/11104/0195358