Synthesis and Characterization of Quinuclidinium Derivatives of the [<i>closo</i>-1-CB₁₁H₁₂]⁻ Anion as Potential Polar Components of Liquid Crystal Materials

Antipodal substitution of the [<i>closo</i>-1-CB₁₁H₁₂]⁻ anion with a 4-pentylquinuclidinium fragment and alkyl groups in positions C(1) and B(12) gave polar zwitterions <b>1­[n]</b> and <b>2­[n]</b>. The molecular structure of <b>1­[5]</b> was established using X-ray diffraction (XRD) methods: <i>P</i>1̅, <i>a</i> = 15.162(2) Å, <i>b</i> = 16.546(3) Å, <i>c</i> = 19.794(3) Å; α = 84.871(2)°, β = 84.057(2)°, γ = 84.058(3)°; <i>Z</i> = 8. All compounds exhibit high temperature in-plane ordered smectic phases that are stabilized by dipolar interactions. The ordered phases were investigated by powder XRD methods. Thermal and dielectric parameters for two derivatives, <b>1­[0]</b> and <b>1­[6]</b>, were evaluated in nematic hosts, <b>ClEster</b> and <b>BPhF</b>. The dielectric data were analyzed with the Maier-Meier formalism augmented with density functional theory methods, and the results were compared to those for similar zwitterions previously reported