A C₁-symmetric hexapole helicene (HH) and a C₃-symmetric dodecapole helicene (DH) were prepared, and their three-dimensional structures were verified by X-ray crystallography and density functional theory calculations. The molecular geometries and local helical configurations of their most stable diastereomers were correctly predicted by arranging suitable conformations of the peripheral aryl rings. Importantly, the outermost three [5]helicenes with a consistent configuration in DH were observed to increase the thermostability, enantiomerization barrier (ΔH^⧧ = 40.5 kcal/mol), specific rotation ([α]₂₄^D = −4228°) and absorption dissymmetry factor (g_abs = 1.35 × 10^–3 at 453 nm).

中文翻译：

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具有多螺旋性的稠合芳烃的合成、结构分析和性质


制备了C ₁对称六极螺旋烯(HH)和C ₃对称十二极螺旋烯(DH)，并通过X射线晶体学和密度泛函理论计算验证了它们的三维结构。通过排列外围芳环的合适构象，可以正确预测其最稳定的非对映异构体的分子几何形状和局部螺旋构型。重要的是，观察到DH中具有一致构型的最外层三个[5]螺旋烯增加了热稳定性、对映异构化势垒（Δ H ^⧧ = 40.5 kcal/mol）、比旋光度（[α] ₂₄ ^D = -4228°）和吸收不对称因子（453 nm 处g _abs = 1.35 × 10 ^–3 ）。