Synthesis, cation exchange, and optical properties of pyrene-based chromophores containing [CB₉H₉]⁻ and [CB₁₁H₁₁]⁻ cluster units

Four monocarborane anion-based compounds connected to a pyrene moiety were synthesized by combining two monocarborane anion scaffolds and two counter cations. The effects of the cage structure and the counter cation on the optical properties were investigated from UV-vis absorption and photoluminescence (PL) measurements. The PL spectra in the solid state were unique for each compound, derived from the different shapes of the carborane cage and counter cation. These results suggest great potential for designing a monocarborane anion-based chromophore.