On the Convergence of the Physicochemical Properties of [n]Helicenes

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• 作者：Lubom&iacute ; r Rul&iacute ; ek ; Otto Exner ; Lukasz Cwiklik ; Pavel Jungwirth ; Ivo Star ; Lubom&iacute ; r Posp&iacute ; il ; Zdenk Havlas
• 刊名：Journal of Physical Chemistry C
• 出版年：2007
• 出版时间：October 18, 2007
• 年：2007
• 卷：111
• 期：41
• 页码：14948 - 14955
• 全文大小：319K
• 年卷期：v.111,no.41(October 18, 2007)
• ISSN：1932-7455

文摘

The results of a series of DFT and DFT-D calculations are reported with the aim to predict the physicochemicalproperties (equilibrium structures, stabilization energies, redox potentials, excitation and CD spectra, electronicconductivity, and elasticity) of elongating helical structures (i.e., [n]helicenes, n = 1-14). It was shown thatmany of them are converged at [14]helicene with an interpitch distance of R_pitch = 3.75 Å, an incrementalstabilization energy of G_n = 11 kJ mol^-1 (thus suggesting the inherent destabilization of the growing helicalstructures), an S₀-S₁ energy difference to the estimated band gap of 2.60 eV, and redox potentials,corresponding to the reduction of [n]helicenes, of E⁰ = -2.2 V. The elasticity was shown to decrease as alinear function of m (i.e., k m) with k = 0.01056 a.u. for [14]helicene. Moreover, the conductivity propertieswere discussed in terms of hole and excess electron densities. Possible implications of the calculated data innanoscience are discussed.