Metal-Promoted Fusion and Linkage of B5H81-, 1-XB5H71-, (X = D, CH3), B10H131-, and (ε5-C5H5)CoB4H71-. Facile Routes to B10H14 and (η5-C5H5)2Co2B8H10 Isomers.

Article abstract of DOI:10.1021/ja00298a025

This study examined the conversions, via oxidative fusion or coupling, of B5H8^1- to B10H14 and 2,2'-(B5H8)2 in the presence of FeCl2/FeCl3, of B5H8^1- to B10H14 alone in the presence of RuCl3, and of 1-XB5H7^1- (X = D and CH3) to 2,4-B10H12D2 and 2,2-(1-CH3B5H7)2 with RuCl3 or FeCl2/FeCl3.The B10H13^1- ion was shown to form n- and i-B18H22 on treatment with RuCl3 in THF and subsequent exposure to air.The RuCl3-promoted fusions of the square-pyramidal cobaltaboranes 2-(ε⁵-C5H5)CoB4H7^1- and 1-(ε⁵-C5H5)CoB4H7^1- (both analogues of B5H8^1- to give nido-(η-C5H5)2Co2B8H12 isomers were also studied.The 2-isomer yields primarily 5,8-, 1,5-, and 1,7-(η-C5H5)2Co2B8H12, while the 1-isomer affords only 2,4-(η⁵-C5H5)2Co2B8H12.All these observations support a fusion mechanism in which two square-pyramidal substrate molecules, facilitated by coordination to a common metal ion, are initially joined at their basal edges and then complete the fusion process to give a nido 10-vertex cage in which the original apex (1-vertex) atoms become the 2,4-vertexes in the product.The new compounds were characterized via infrared, 11B and 1H NMR, mass spectra, and in some cases by two-dimensional (2D) 11B homonuclear NMR.