Metal-Promoted Fusion and Linkage of B5H8-, 1-XB5H7-(X = D, CH3), B10H13-, and (n5-C5H5)CoB4H7-. Facile Routes to B10H14 and (n5-C5H5)2Co2B8H10 Isomers

摘要

This study examined the conversions, via oxidative fusion or coupling, of B5H8- to B10H14 and 2,2-(B5H8) in the presence of FeC12/FeCl3 of B5H8 to B10H14 alone in the presence of RuC13 and of X-XB5H7-(X=D and CH3) to 2,4-B10H12D2 and 2,2-(1-CH3B5H7)2 with RuC13 or FeC12/FeC13. The B10H13 ion was shown to form n-and i-B18H22 on treatment with RuC1 in THF and subsequent exposure to air. The RuC13-promoted fusions fo the square-pyramidal cobaltabornaes 2-eta5-C5H5)CoB4H7-(both analogues of B5H8-) to give nido(n5-C5H5)2C02B8H12 isomers were also studied. The 2-isomer yields primarily 5,8- 1,5-, and 1,7 (eta5-C5h5)2Co2B8H12, while the 1-isomer affords only 2,4(eta5-C5H4)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-vertx 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.