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The primary purpose of this work was to demonstrate the suitability of circular dichroism (CD) spectroscopy in stereochemical studies of α,β-unsaturated oximes, with particular emphasis on determination of E and Z geometry of the oxime double bond. As models for this study, O-phenyl and O-triphenylmethyl (trityl) oximes of 4-hydroxy-2-methylcyclopent-2-en-1-one were selected. These model compounds differ in both absolute configuration at C4 carbon atom and E-Z configuration of the oxime double bond. The basic dichroic technique applied was electronic circular dichroism (ECD) assisted by quantum-chemical calculations and vibrational circular dichroism (VCD) for selected cases. Such an approach enabled effective implementation of both goals. Thus, we were able to associate the signs of Cotton effects in the range of 190-240 nm with the absolute configuration at C4 and within 240-300 nm with the E- or Z-geometry of the oxime double bond. Within this work, optical activity of the protecting trityl group was also studied towards formation of the propeller-shaped conformations by using the same combined CD/DFT methodology. As shown, the helical structure of the trityl group has a considerable influence on the ECD spectra. However, the MPM and PMP conformers of the trityl group are in fact almost equally populated in the conformational equilibrium, making it impossible to distinguish them. On the other hand, rotamers of the hydroxyl group at C4 show a decisive impact on the VCD spectra in both phenoxy and trityl oximes.

The absolute configuration of plakinidone (I) is re-assigned as (11S,17R) from the formerly reported (11S,17S) diastereomer.

For the first time the argon-matrix low-temperature FTIR spectra of beta-alanine are recorded. They reveal a quite complicated spectral pattern which suggests the presence of several beta-alanine conformers in the matrix. To interpret the spectra, the eighteen beta-alanine conformers, stable in the gas phase, are estimated at the B3LYP and MP2 levels combined with the aug-cc-pVDZ. Ten low-energy structures are reoptimized at the QCISD/aug-cc-pVDZ and B3LYP and MP2 levels by using the aug-cc-pVTZ basis sets. Assignment of the experimental spectra is undertaken on the basis of the calculated B3LYP/aug-cc-pVDZ anharmonic IR frequencies as well as careful estimation of the conformer population. The presence of at least three beta-alanine conformers is demonstrated. The detailed analysis of IR spectra points to the possible presence of five additional beta-alanine conformers.

A new oxidizing system for olefins, consisting of benzeneseleninic anhydride and trimethylsilyl triflate, was studied. The highly reactive benzeneseleninyl cation is presumably formed under these conditions. It has been shown that different products are formed with this species depending on the specific structure of olefin. The 1,1-disubstituted olefins afforded mostly α,β-unsaturated carbonyl compounds. The sterically encumbered tri- or tetrasubstituted olefins yielded 1,2- or 1,4-dihydroxylated products, presumably via four-membered cyclic intermediates.

Eleven exchange-correlational functionals of different types corrected for dispersion by Grimme's D3 correction in conjunction with the aug-cc-pVTZ basis set were tested on the following noble gas (Ng) dimers: Ne2, Ar2, Kr2, Xe2, and Rn2. For comparison, the D2 and D3BJ corrections were probed with the B3LYP functional. From post-HF wavefunction methods, CCSD(T) theory was also included. The investigated properties involved potential energy curves, equilibrium bond distances, and interaction energies. The B3LYP-D3, B3LYP-D3BJ, and PBE0-D3 functionals performed overall best for bond distances, while B3LYP-D3 and B97-D3 performed best for interaction energies. The importance of fortunate error cancellations was seen in the often reduced agreement with reference data upon correction for BSSE. As several functionals performed well selectively for some noble gases (and poorly for others), we also analysed the performance on the Ng2 dimers individually and recommended DFT-D3 functionals for the calculation of large clusters of each Ng.

Most of the research in contemporary physical chemistry is devoted to the development of methods that extend our understanding, interpretation, and capacity to predict structural properties and dynamic behavior of molecules. The optical and magnetic spectroscopies, as well as diffraction techniques, are the principal methods for studying properties of molecules, biomolecules, and biopolymers of which the vast majority are chiral. On the other hand, information on molecular configuration can be obtained mainly from optical spectroscopies because other well-established spectroscopic techniques used for structural investigations, such as crystallographic, ESR, and NMR methods, do not allow for registration of signals from an individual conformer owing to intrinsic slow response to structural changes. This is the reason why the optical spectroscopy methods, based on natural chiroptical phenomena, have become so important and their renaissance in the last decade is noticed. Vibrational circular dichroism (VCD) spectroscopy is one such chiroptical technique that sheds new light on many important phenomena studied intensively. We provide an overview of recent theoretical predictions and innovative VCD observations of chirality transfer (called by other authors “induced chirality”) from a chiral molecule to an achiral one as a result of hydrogen bond interactions between them. In this tutorial review we search for answers as to whether we can obtain further information about intermolecular interactions using the VCD technique. In our opinion this technique has opened new horizons for both understanding and monitoring intermolecular interactions and it could be used as a relatively new and powerful physicochemical method.