Interaction of Cyclosporin C with Dy Ions in Acetonitrile and in Complex with Dodecylphosphocholine Micelles Determined by NMR Spectroscopy.

The spectral characteristics of cyclosporin C (CsC) with the addition of Dy ions in acetonitrile (CDCN) and CsC with Dy incorporated into dodecylphosphocholine (DPC) micelle in deuterated water were investigated by high-resolution NMR spectroscopy. The study was focused on the interaction between Dy ions and CsC molecules in different environments. Using a combination of one-dimensional and two-dimensional NMR techniques, we obtained information on the spatial features of the peptide molecule and the interaction between CsC and the metal ion.

Influence of Solvent Polarity on the Conformer Ratio of Bicalutamide in Saturated Solutions: Insights from NOESY NMR Analysis and Quantum-Chemical Calculations.

The study presents a thorough and detailed analysis of bicalutamide's structural and conformational properties. Quantum chemical calculations were employed to explore the conformational properties of the molecule, identifying significant energy differences between conformers. Analysis revealed that hydrogen bonds stabilise the conformers, with notable variations in torsion angles.

C-H-activated Csp-Csp diastereoselective gridization enables ultraviolet-emitting stereo-molecular nanohydrocarbons with mulitple H···H interactions.

Gridization is an emerging molecular integration technology that enables the creation of multifunctional organic semiconductors through precise linkages. While Friedel-Crafts gridization of fluorenols is potent, direct linkage among fluorene molecules poses a challenge. Herein, we report an achiral Pd-PPh-cataylized diastereoselective (>99:1 d.

Correction: Mamardashvili et al. New Polyporphyrin Arrays with Controlled Fluorescence Obtained by Diaxial Sn(IV)-Porphyrin Phenolates Chelation with Cu Cation. 2021, , 829.

In the original publication [...

Conformational Analysis of 1,5-Diaryl-3-Oxo-1,4-Pentadiene Derivatives: A Nuclear Overhauser Effect Spectroscopy Investigation.

1,5-Diaryl-3-Oxo-1,4-Pentadiene derivatives are intriguing organic compounds with a unique structure featuring a pentadiene core, aryl groups, and a ketone group. This study investigates the influence of fluorine atoms on the conformational features of these derivatives in deuterated chloroform (CDCl) solution. Through nuclear magnetic resonance (NMR) spectroscopy and quantum chemical calculations, we discerned variations in interatomic distances and established predominant conformer proportions.

meso-Bromination of cyano- and aquacobalamins facilitates their processing into Co(II)-species by glutathione.

Cyanocobalamin (CNCbl), a medicinal form of vitamin B, is resistant to glutathione (GSH), and undergoes intracellular processing via reductive decyanation producing the Co(II)-form of Cbl (Cbl(II)) mediated by the CblC-protein. Alteration of the CblC-protein structure might inhibit CNCbl processing. Here, we showed that introducing a bromine atom to the C10-position of the CNCbl corrin ring facilitates its reaction with GSH leading to the formation of Cbl(II) and cyanide dissociation.

Conformational State of Fenamates at the Membrane Interface: A MAS NOESY Study.

The present work analyzes the H NOESY MAS NMR spectra of three fenamates (mefenamic, tolfenamic, and flufenamic acids) localized in the lipid-water interface of phosphatidyloleoylphosphatidylcholine (POPC) membranes. The observed cross-peaks in the two-dimensional NMR spectra characterized intramolecular proximities between the hydrogen atoms of the fenamates as well as intermolecular interactions between the fenamates and POPC molecules. The peak amplitude normalization for an improved cross-relaxation (PANIC) approach, the isolated spin-pair approximation (ISPA) model, and the two-position exchange model were used to calculate the interproton distances indicative of specific conformations of the fenamates.

Accurate prediction of B NMR chemical shift of BODIPYs machine learning.

In this article, we present the results of developing a model based on an RFR machine learning method using the ISIDA fragment descriptors for predicting the B NMR chemical shift of BODIPYs. The model is freely available at https://ochem.eu/article/146458.

Conformational and Supramolecular Aspects in Chirality of Flexible Camphor-Containing Schiff Base as an Inducer of Helical Liquid Crystals.

The experimental and theoretical study of influence of the conformational state and association on the chirality of the stereochemically nonrigid biologically active bis-camphorolidenpropylenediamine (CPDA) and its ability to induce the helical mesophase of alkoxycyanobiphenyls liquid-crystalline binary mixture was carried out. On the basis of quantum-chemical simulation of the CPDA structure, four relatively stable conformers were detected. A comparison of the calculated and experimental electronic circular dichroism (ECD) and H, C, N NMR spectra, as well as specific optical rotation and dipole moments, allowed to establish the most probable trans-gauche conformational state (tg) of dicamphorodiimine and CPDA dimer with a predominantly mutually parallel arrangement of molecular dipoles.

Synthesis and Design of Hybrid Metalloporphyrin Polymers Based on Palladium (II) and Copper (II) Cations and Axial Complexes of Pyridyl-Substituted Sn(IV)Porphyrins with Octopamine.

Supramolecular metalloporphyrin polymers formed by binding tetrapyrrolic macrocycle peripheral nitrogen atoms to Pd(II) cations and Sn(IV)porphyrins extra-ligands reaction centers to Cu(II) cations were obtained and identified. The structure and the formation mechanism of obtained hydrophobic Sn(IV)-porphyrin oligomers and polymers in solution were established, and their resistance to UV radiation and changes in solution temperature was studied. It was shown that the investigated polyporphyrin nanostructures are porous materials with predominance cylindrical mesopores.

Investigation of the Spatial Structure of Flufenamic Acid in Supercritical Carbon Dioxide Media via 2D NOESY.

The search for new forms of already known drug compounds is an urgent problem of high relevance as more potent drugs with fewer side effects are needed. The trifluoromethyl group in flufenamic acid renders its chemical structure differently from other fenamates. This modification is responsible for a large number of conformational polymorphs.

Molecular Dynamics and Nuclear Magnetic Resonance Studies of Supercritical CO Sorption in Poly(Methyl Methacrylate).

The study of supercritical carbon dioxide sorption processes is an important and urgent task in the field of "green" chemistry and for the selection of conditions for new polymer material formation. However, at the moment, the research of these processes is very limited, and it is necessary to select the methodology for each polymer material separately. In this paper, the principal possibility to study the powder sorption processes using C nuclear magnetic resonance spectroscopy, relaxation-relaxation correlation spectroscopy and molecular dynamic modeling methods will be demonstrated based on the example of polymethylmethacrylate and supercritical carbon dioxide.

Amine-Reactive BODIPY Dye: Spectral Properties and Application for Protein Labeling.

A boron-dipyrromethene (BODIPY) derivative reactive towards amino groups of proteins () was synthesized. Spectroscopic and photophysical properties of amine-reactive and its non-reactive precursor () in a number of organic solvents were investigated. Both fluorescent dyes were characterized by green absorption (521-532 nm) and fluorescence (538-552 nm) and medium molar absorption coefficients (46,500-118,500 M·cm) and fluorescence quantum yields (0.

Mechanism of cyanocobalamin chlorination by hypochlorous acid.

Hypochlorous acid (HOCl) is a strong oxidant produced by myeloperoxidase. Previous work suggested that HOCl modifies the corrin ring of cobalamins to yield chlorinated species via mechanisms that are incompletely understood. Herein, we report a mechanistic study on the reaction between cyanocobalamin (CNCbl, vitamin B) and HOCl.

New Polyporphyrin Arrays with Controlled Fluorescence Obtained by Diaxial Sn(IV)-Porphyrin Phenolates Chelation with Cu Cation.

New coordination oligomers and polymers of Sn(IV)-tetra(4-sulfonatophenyl)porphyrin have been constructed by the chelation reaction of its diaxialphenolates with Cu. The structure and properties of the synthesized polyporphyrin arrays were investigated by H Nuclear Magnetic Resonance (H NMR), Infra Red (IR), Ultra Violet - Visible (UV-Vis) and fluorescence spectroscopy, mass spectrometry, Powder X-Rays Diffraction (PXRD), Electron Paramagnetic Resonance (EPR), thermal gravimetric, elemental analysis, and quantum chemical calculations. The results show that the diaxial coordination of bidentate organic ligands (L-tyrazine and diaminohydroquinone) leads to the quenching of the tetrapyrrole chromophore fluorescence, while the chelation of the porphyrinate diaxial complexes with Cu is accompanied by an increase in the fluorescence in the organo-inorganic hybrid polymers formed.

Exposing Hidden Conformations of Carbamazepine Appearing Due to Interaction With the Solid Phase by 2D H-N HMBC NMR Spectroscopy.

Two-dimensional H-N HMBC NMR spectra of the well-known anticonvulsant carbamazepine dissolved in different organic solvents, recorded on an NMR spectrometer prove the existence of hidden conformers in saturated solutions. Obtained conformer distribution arises due to the presence of the solid phase in saturated solution. A weak influence of ring currents was revealed for different molecular conformations of carbamazepine dissolved in a saturated solution, which provides a simple approach to discovering hidden conformations.

La(III), Ce(III), Gd(III), and Eu(III) Complexation with Tris(hydroxymethyl)aminomethane in Aqueous Solution.

Lanthanides such as cerium(III), europium(III), and gadolinium(III) are widely used for designing fluorescent probes or magnetic resonance imaging contrasting agents for biological systems. The synthesis and study of lanthanide complexes in buffer solutions imitating biological fluids are often complicated because of a lack of data on the lanthanide interactions with buffer solution components. Therefore, Ln(III) [where Ln(III) = La(III), Ce(III), Gd(III), Eu(III)] complexation with a widely used buffer agent, tris(hydroxymethyl)aminomethane (Tris), in aqueous solution is studied using potentiometry, spectrofluorimetry, and La NMR spectroscopy.

Comparison of cyclosporin variants B-E based on their structural properties and activity in mitochondrial membranes.

Cyclosporins B, C, D, and E were characterized by NMR spectroscopy, and backbone flexibility was studied by molecular dynamics simulation. Structures of the molecules were characterized by nuclear Overhauser effect spectroscopy, which revealed that the studied peptides have many common features. Molecular dynamics simulation showed that the backbone of cyclosporin E is relatively more rigid than in other peptides.