title: Electrochemical and spectroelectrochemical studies of C-benzodiazaborolyl-ortho-carboranes.
abstract: Fifteen C-diazaborolyl-ortho-carboranes, 1-R'-2-R''-1,2-C(2)B(10)H(10), where R' represents the groups 2-(1,3-Et(2)-1,3,2-N(2)BC(6)H(4))-, 2-(1,3-Ph(2)-1,3,2-N(2)BC(6)H(4))-, 2-(1,3-Ph(2)-5,6-Me(2)-1,3,2-N(2)BC(6)H(2))-, 2-(1,3-(i)Pr(2)-1,3,2-N(2)BC(6)H(4))-, and 2-(1,3,2-N(2)BC(6)H(6))- and where R'' is H, Me, Ph, (t)Bu or SiMe(3), were synthesized. Cyclic voltammetry studies of the compounds showed irreversible oxidation waves which are caused by the oxidation of the heterocycle. Those C-diazaborolyl-ortho-carboranes with Ph, tBu and SiMe(3) substituents at the adjacent C-atom of the cage displayed two one-electron reduction waves reflecting the formation of stable radical monoanions with unusual (2n + 3) skeletal electron counts. The geometries of these anions were determined by combinations of infrared, UV-visible spectroelectrochemical and computational studies. Additionally the structures of seven new C-diazaborolyl-ortho-carboranes and one new 2-bromo-1,3,2-benzodiazaborole were determined by X-ray crystallography and compared with previously obtained structures.
authors.affiliation: Fakultät für Chemie der Universität Bielefeld, 33615 Bielefeld, Germany. lothar.weber@uni-bielefeld.de
authors.forename: Lothar
authors.initials: L
authors.lastname: Weber
authors.forename: Jan
authors.initials: J
authors.lastname: Kahlert
authors.forename: Lena
authors.initials: L
authors.lastname: Böhling
authors.forename: Andreas
authors.initials: A
authors.lastname: Brockhinke
authors.forename: Hans-Georg
authors.initials: HG
authors.lastname: Stammler
authors.forename: Beate
authors.initials: B
authors.lastname: Neumann
authors.forename: Rachel A
authors.initials: RA
authors.lastname: Harder
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Low
authors.forename: Mark A
authors.initials: MA
authors.lastname: Fox