Nature of intramolecular interactions in hypercoordinate C-substituted 1,2-dicarba-closo-dodecaboranes with short P⋯P distances

Experimental and computational evidence show that there is short intramolecular distance between two phosphorus atoms in 1,2-(diphenylphosphino)-1,2-dicarba-closo-dodecaborane. At the B3LYP/6-31G∗ level, quantum theory - atoms-in-molecules indicates direct P⋯P interaction, while natural bonding orbitals describes it mainly as donor-acceptor interaction between phosphorus electron lone pair and adjacent antibonding P-C(phenyl) orbital.