New carboranes and phosphaboranes

Abstract

A review is presented on the new routes to the synthesis of the monocarbaboranes [arachno-6-CB9H14]–, arachno-4-CB8H14, and nido-1-CB8H12, that now have become excellent starting materials for the preparation of a family of seven-, eight-, and nine-vertex closo-monocarbaborane anions [2-CB6H7]–, [1-CB7H8]–, and [4-CB8H9]–. These anions exhibit high stability and have a good chance to become new candidates for weakly coordinated anion chemistry. Discussed are also reactions leading new families of phosphacarboranes that contain one, two, and three phosphorus atoms in the cage. These compounds, namely closo- 2,1-PCB8H9, closo-6,1-PCB8H9, nido -7,8,9-PC2B8H11, nido-7,8,11-PC 2B8H11, and nido- 7,8,9,10-P3CB7H8 ,are structural analogs of the corresponding carboranes and are likely to exhibit similar chemical behavior.