Halogenation of tris(amido)tantalacarboranes with dihalomethanes CH2X2 (X = Cl, Br)

Fox, M.A.; Goeta, A.E.; Hughes, A.K.; Malget, J.M.; Wade, K.

Abstract

Slow reactions of isomeric metallacarboranes of general formulae [(NMe2)(3)TaC2B9H11] (3 isomers) and [(NMe2)(3) TaC2B9H10Me] (3 isomers) with CD2Cl2 afford quantitative yields of monochloro complexes [Cl(NMe2)(2)TaC2B9H11] and [Cl(NMe2)(2) TaC2B9H10Me]. Exposure to CD2Cl2 for months leads to solutions containing about 70% of the dichlorides in three cases. More prolonged exposure of these and the other monochlorides leads to a mixture of boron-substituted complexes. Hydrolysis of [3,3,3-(NMe2)(3)-3,1,2-TaC2B9H11] by moist toluene results in the formation of the oxo-bridged complex 3,3-[3,3-(NMe2)(2) 3,1,2-TaC2B9H11] (2) (mu-O), characterised by single-crystal X-ray crystallography. The limited solubility of the latter complex in CD2Cl2 eliminates the presence of this compound in the reaction of [3,3,3-(NMe2)(3)-3,1,2-TaC2B9H11] with CD2Cl2. The reaction of [2,2,2-(NMe2)(3) 2,1,12-TaC2B9H11]with CH2Br2 in C6D6 quantitatively yields the monobromide [2-Br-2,2-(NMe2)(2)-2,1,12-TaC2B9H11]. Prolonged reaction with CH2Br2 leads directly to isomeric boron-substituted complexes with no evidence for dibromides. The influence on B-11, C-13 and H-1 NMR chemical shifts of replacing an amide group in [(NMe2)(3)TaC2B9H11] with chloride to give [Cl(NMe2)(2)TaC2B9H11] is also discussed.

Citation

Fox, M., Goeta, A., Hughes, A., Malget, J., & Wade, K. (2002). Halogenation of tris(amido)tantalacarboranes with dihalomethanes CH2X2 (X = Cl, Br)

• Journal Article Type: Article
• Publication Date: 2002
• Journal: Collection of Czechoslovak chemical communications.
• Peer Reviewed: Peer Reviewed
• Volume: 67
• Issue: 6
• Pages: 791-807