Faculty of Chemistry, University of Warsaw, Pasteura 1, 02-093 Warszawa, Poland.
Phys Chem Chem Phys. 2011 Jan 14;13(2):643-50. doi: 10.1039/c0cp01149e. Epub 2010 Oct 29.
The circularly polarized luminescence (CPL) and electronic circular dichroism (CD) spectroscopic parameters corresponding to the n←π* and n→π* transitions, respectively, have been calculated for selected β,γ-enones using density functional theory. For the smallest β,γ-enone, (1R,4R)-bicyclo[2.2.1]hept-5-en-2-one (norbornenone), coupled-cluster calculations have also been carried out. The excited-state potential energy surface for three of the five enones studied reveals two minima with different C[double bond, length as m-dash]OC[double bond, length as m-dash]C dihedral angles, and with rotatory strengths of opposite sign. The relative energies of the minima determine the sign of the CPL intensity, which may be the same or opposite as in the CD spectrum, in agreement with experimental data. The results obtained in this first computational study of CPL demonstrate its usefulness as an indicator of excited-state structures of chiral species.
用密度泛函理论计算了所选β，γ-烯酮的分别对应于n←π和n→π跃迁的圆偏振发光（CPL）和电子圆二色性（CD）光谱参数。对于最小的β，γ-烯酮（1R，4R）-双环[2.2.1]庚-5-烯-2-酮（降冰片烯酮），还进行了耦合簇计算。所研究的五个烯酮中的三个的激发态势能面揭示了两个不同的 C[双键，长度为 m-dash]OC[双键，长度为 m-dash]C 二面角的最小值，并且具有相反符号的旋转强度。最小的相对能量确定了 CPL 强度的符号，该符号可能与 CD 光谱中的符号相同或相反，与实验数据一致。这项对 CPL 的首次计算研究的结果证明了它作为手性物质激发态结构的指示剂的有用性。
