Controlling Chirogenic Effects in Porphyrin Based Supramolecular Systems: Theoretical Analysis Versus Experimental Observations.

Electronic circular dichroism (ECD) spectroscopy is a widely employed method for studying chiral analysis, requiring the presence of a chromophore close to a chiral centre. Porphyrinoids are found to be one of the best chromophoric systems serving for this purpose and enabling the application of ECD spectroscopy for chirality determination across diverse classes of organic compounds. Consequently, it is crucial to understand the induction mechanisms of ECD in the porphyrin-based complexes.

Supramolecular Chirogenesis in a Sterically Hindered Porphyrin: A Critical Theoretical Analysis.

Invited for the cover of this issue are the groups of Irina Osadchuk at Tallinn University of Technology and Mathias Senge at Trinity College Dublin. The image depicts how a porphyrin with two guest molecules (R)-camphor sulfonic acid is irradiated with UV-visible light to measure and simulate ECD and UV-Vis spectra. Read the full text of the article at 10.

Complexes of HXeY with HX (Y, X = F, Cl, Br, I): Symmetry-Adapted Perturbation Theory Study and Anharmonic Vibrational Analysis.

A comprehensive analysis of the intermolecular interaction energy and anharmonic vibrations of 41 structures of the HXeY⋯HX (X, Y = F, Cl, Br, I) family of noble-gas-compound complexes for all possible combinations of Y and X was conducted. New structures were identified, and their interaction energies were studied by means of symmetry-adapted perturbation theory, up to second-order corrections: this provided insight into the physical nature of the interaction in the complexes. The energy components were discussed, in connection to anharmonic frequency analysis.

Supramolecular Chirogenesis in a Sterically Hindered Porphyrin: A Critical Theoretical Analysis.

The determination of molecular stereochemistry and absolute configuration is an important part of modern chemistry, pharmacology, and biology. Electronic circular dichroism (ECD) spectroscopy is a widely used tool for chirality assignment, especially with porphyrin macrocycles employed as reporter chromophores. However, the mechanisms of induced ECD in porphyrin complexes are yet to be comprehensively rationalized.

Importance of molecular symmetry for enantiomeric excess recognition by NMR.

Recently prochiral solvating agents (-CSA) came under the spotlight for the detection of enantiopurity by NMR. Chemical shift non-equivalency in achiral hosts introduced by the presence of chiral guests yields observable resonance signal splitting (Δ) correlating to the enantiomeric excess (e.e.

Chirogenesis in Zinc Porphyrins: Theoretical Evaluation of Electronic Transitions, Controlling Structural Factors and Axial Ligation.

In the present work, sixteen different zinc porphyrins (possessing different meso substituents) with and without a chiral guest were modelled using DFT and TD-DFT approaches in order to understand the influence of various controlling factors on electronic circular dichroism (ECD) spectra. Two major aspects are influenced by these factors: excitation energy of the electronic transitions and their intensity. In the case of excitation energy, the influence increases in the following order: orientation of the peripheral substituents View Article and Find Full Text PDF

Benchmarking computational methods and influence of guest conformation on chirogenesis in zinc porphyrin complexes.

Circular dichroism (CD) is a convenient and widely used tool for investigating structures of chiral molecules. However, the unambiguous simulation of CD spectra is not a trivial task, because the accuracy of theoretical calculations depends on the nature of the system. In the present work, the induced CD spectra of six zinc porphyrin complexes with chiral guests were simulated by using different DFT methods.