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Density Functional Theory (DFT) calculations of optical rotation (OR) and vibrational circular dichroism (VCD) have been used to assign the absolute configuration (AC) of a recently prepared (3‐phenyloxirane‐2,2‐diyl)bis(phenylmethanone), 3, by asymmetric epoxidation of the corresponding 2‐arylidene‐1,3‐diketone. The experimental OR at 589.3 nm and the VCD spectrum of the (+)‐ and (−)‐enantiomer of...
In this article, the most advanced extensions of solvation models to chiroptical properties of solvated systems will be reviewed. The main aspects determining the complex phenomenon of solvation will be first discussed in terms of the physical interactions beyond them and successively translated in a computational language introducing the specific models. A particular attention will be devoted to...
The effect of conformational flexibility on the chiroptical properties of a series of synthetic (3R)‐3‐hydroxy‐4‐aryl‐β‐lactams of known stereochemistry (1–6) was investigated by means of electronic circular dichroism (ECD) measurements and time‐dependent density functional theory (TD‐DFT) calculations. The application of the β‐lactam sector rules allowed a correct stereochemical characterization...
This paper aims to inspire experimentalists to carry out proposed new chiroptical experiments springing from the theoretical study of the role of parity violation in the origin of biomolecular homochirality and to provide a brief update on the current status of calculations of the electroweak parity‐violating energy difference (PVED) between enantiomers. If the PVED did select life's handedness, we...
The impressive advances of computational spectroscopy in most recent years are providing robust and user‐friendly multifrequency virtual spectrometers, which can also be used by nonspecialists to complement experimental studies. At the heart of these developments there are latest‐generation models based on Density Functional Theory for the proper treatment of stereo‐electronic effects, coupled to...
The observation of nonequivalence of optical and enantiomeric purities, referred to as the Horeau effect, is thought to arise from molecular aggregation in liquid solutions. Although this effect was first observed in 1969, the conditions under which this effect may, or may not, be observable are not established. Considering the formation of dimers as the simplest form of aggregation, the expressions...
Computing the optical rotation of organic molecules can be a real challenge, and various theoretical approaches have been developed in this regard. A benchmark study of optical rotation of various classes of compounds was carried out by Density Functional Theory (DFT) methods. The aim of the present research study was to find out the best‐suited functional and basis set to estimate the optical rotations...
Four novel tartaric acid–based diastereomeric chiral amphiphiles, two being enantiomers of the other two, have been synthesized and investigated using chiroptical spectroscopic methods, along with tensiometry and dynamic light scattering experiments. We found that an inflection point in specific optical rotation (SOR) values at ~0.32 mM corresponds to the critical micelle concentration (CMC). The...
In a recent letter on the “Optical activity from racemates”, discussed at the 16th International Conference on Chiroptical Spectroscopy in Rennes (June 2017), scientists claimed to have measured the circular dichroism of colored, racemic crystals of two transition metal complexes, observations that “serve to correct a clear deficit in our understanding of the optical properties of racemates.” In fact,...
The anisotropy of the optical activity of cyclo[18]carbon (C18), fully hydrogenated C18 (C18H36), and 26 hydrogenated compounds of intermediate composition, C18H2n, n = 1,2…17, were computed. These compounds were selected because they resemble loops of wire. The maximum gyration for acetylenic and cumulenic subgroups of compounds was linearly proportional to the product of the geometric area over...
Accurate polarimetric measurements of the optical activity of crystals along low symmetry directions are facilitated by isotropic points, frequencies where dispersion curves of eigenrays cross and the linear birefringence disappears. We report here the optical properties and structure of achiral, uniaxial (point group D2d) potassium trihydrogen di‐(cis‐4‐cyclohexene‐1,2‐dicarboxylate) dihydrate, whose...
Theoretical calculations of optical rotation (OR), although important to predict absolute configurations (ACs) and corroborate experiments, require efficient methodology able to reproduce enantiomer specificity and real OR values. Also, troublesome molecules are recurring in the literature, such as (S)‐methyloxirane and (1R,5R)‐β‐pinene. This study evaluates DFT functionals B3LYP, CAM‐B3LYP, ωB97X‐D,...
In this work, we explore the issue of origin dependence in optical rotation (OR) calculations in the length dipole gauge (LG) using standard approximate methods belonging to density functional theory (DFT) and coupled cluster (CC) theory. We use the origin‐invariant LG approach, LG(OI), that we recently proposed as reference for the calculations, and we study whether a proper choice of coordinate...
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