Pure and Applied Chemistry

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.