nidocarboranes

Nidocarboranes are a class of cage compounds derived from carboranes. Carboranes are a group of boron-containing clusters that also include carbon atoms. Nidocarboranes are characterized by a cage structure where one or more boron atoms have been replaced by a single carbon atom. This distinguishes them from closocarboranes, where all cage vertices are occupied by either boron or carbon atoms in a regular polyhedral arrangement.

The general formula for a nidocarborane is often represented as [C2B(n-1)Hn]2-, where n is the total number of atoms in the cage. The number of vertices in the cage can vary. For example, nido-carboranes with 12 vertices are common and are structurally related to the closo-dicarbadodecaboranes. In these 12-vertex structures, two carbon atoms are present, and the remaining ten vertices are occupied by boron atoms.

The structure of nidocarboranes is typically derived from a deltahedral boron cluster by the formal removal of a single polyhedron vertex and the insertion of a single carbon atom into that vacant position. This results in an open cage structure. The naming convention for nidocarboranes follows that of boranes and carboranes, indicating the number of skeletal atoms and the presence of carbon. Their electronic structure and bonding are often described using Wade's rules, which help predict the geometry of polyhedral boranes and related clusters. Nidocarboranes find applications in areas such as materials science and medicinal chemistry.