Designing a Stable Singlet Phenyl Cation via ortho -Disubstitution with Carborane Anions

The experimental isolation of singlet phenyl cations remains a major challenge. We propose a molecular design for their stabilization using ortho-substitution with two anionic carborane cages, [CB11H12]−. Density Functional Theory (DFT) calculations investigated the generation and stability of the target 2,6-dicarboranylphenyl cation (2,6-C-Ph+). Generation via N2 elimination or fluoride abstraction appears kinetically feasible. Calculations using the benchmarked B1B95 functional confirm a stable singlet ground state. NBO analysis reveals significant electronic stabilization from B–H σ-donation by the anionic cages. Critically, B-vertex attachment was found to be more stable than C-vertex attachment, offering a promising theoretical route toward isolating this reactive intermediate.