Synthesis and structure of 3-arylazo derivatives of ortho -carborane

A series of B-substituted arylazo derivatives of ortho -carborane, 3-XC 6 H 4 -NN-1,2-C 2 B 10 H 11 (X = p -NMe 2 , p -OMe, o -Me), were synthesized by reaction of its diazonium derivative [3-N 2 - o -C 2 B 10 H 11 ][BF 4 ] with aryl Grignard reagents. The treatment of 3-arylazo- ortho -carboranes with CsF in refluxing ethanol results in their selective decapitation with the formation of the corresponding 3-arylazo- nido -carboranes Cs[3-XC 6 H 4 -NN-7,8-C 2 B 9 H 11 ].