Jorge Francisco E, Jorge Sara S, Suave Rogério N
Departamento de Física, Universidade Federal do Espírito Santo, Vitória, Brazil.
Chirality. 2015 Jan;27(1):23-31. doi: 10.1002/chir.22384. Epub 2014 Oct 6.
Time-dependent density functional theory (TDDFT) calculations of electronic circular dichroism (ECD) are widely used to determine absolute configurations (ACs) of chiral molecules. Two very popular DFT exchange-correlation functionals, one hybrid (B3LYP) and one long-range corrected (CAM-B3LYP), along with a hierarchical sequence of basis sets were investigated, and the ECD spectra predicted for eight alkenes and compared to gas-phase experimental spectra. Little variation in predicted ECD spectra was found with the basis set size enlargement, but the sensitivity to the functional is greater. Good agreement was obtained only with the CAM-B3LYP functional, leading to the conclusion that TDDFT calculations of ECD spectra can routinely provide reliable ACs if and only if an appropriate functional is used. For camphene, twistene, syn-(E)-bisfenchylidene, and phyllocladene, solvent effects were estimated.
电子圆二色性（ECD）的含时密度泛函理论（TDDFT）计算被广泛用于确定手性分子的绝对构型（AC）。研究了两种非常流行的密度泛函理论（DFT）交换相关泛函，一种是杂化泛函（B3LYP），另一种是长程校正泛函（CAM-B3LYP），以及一系列分级基组，并预测了八种烯烃的ECD光谱，并与气相实验光谱进行了比较。随着基组尺寸的增大，预测的ECD光谱变化很小，但对泛函的敏感性更大。仅使用CAM-B3LYP泛函时才获得了良好的一致性，从而得出结论，只有使用适当的泛函，ECD光谱的TDDFT计算才能常规地提供可靠的绝对构型。对于莰烯、扭曲烯、顺式-（E）-双葑叉基和叶状枝烯，估计了溶剂效应。
