Oxidation of the [nido-6,9-C_2B_8H_(10)]~(2-) anion - an alternative source of the 1,6- and 1,10-dicarba-closo-decaboranes(10)

摘要

The oxidation of the [nido-6,9-C_2B_8H_(10)]~(2-) (1) dianion with CuCl_2, is supposed to proceed via an unstable closo-2,6-C_2B_8H_(10) (2) intermediate, which is then rearranged into closo-1,6-C_2B_8H_(10) (3) (yields 30-35%). The synthesis is accompanied by the formation of the isomeric closo-dicarbaboranes 1,10-C_2B_8H_(10) (4) and 1,2-C_2B_8H_(10) (5) and the whole procedure can be modified to isolate only isomer 4 (yield 35%). Side products from the synthesis consist of a complex and so far unseparable mixture, in which arachno-4,6-C_2B_7H_(13), chloro derivatives closo-C_2B_8H_9Cl, and trimeric compounds of a closo-(C_2B_8H_9)_2-C_2B_8H_8 formulation were detected by GLC/MS techniques. These findings point to the involvement of a radicalchain mechanism in the reaction.