A RETURN TO THE PLESEK REACTION AND SOME USEFUL VARIATIONS - CARBON-SUBSTITUTED METHYL AND PHENYL DERIVATIVES OF 5,6-DICARBA-NIDO-DECABORANE(12), NINO-5,6-C2B8H12

A modification of the Plesek reaction has been employed to improve the yield in the synthesis of the parent nido ten-vertex dicarbaborane 5, 6-C2B8H12, and to synthesize some of its 5- and 6-substituted derivati ves. The method is based on the oxidation of the anions [7,8-(RR2)-R-1 -nido-5,6-C2B9H10](-) with acidic aqueous of [Fe(H2O)(6)]Cl-3 to produ ce the series of substituted dicarbaboranes 5,6-(RR2)-R-1-nido-5,6-C2B 8H10, where R-1, R-2 = H, H; H, Me; Me, H; Me, Me; H, Ph; Ph, H, and P h, Ph. The characteristic reaction mode is an oxidative elimination of one boron vertex that is adjacent to the carbon vertex in the open pe ntagonal face of the starting eleven-vertex nido dicarbaborane anion. The products are characterized by mass spectrometry and H-1 and B-11 N MR spectroscopy including [B-11-B-11]-COSY and H-1-{B-11(selective)} m easurements that permit complete assignments of all the observed reson ances to individual cluster {BH} units.