Accuracy of determination of self-diffusion coefficients in studies of porphyrin-based complexes by 2D DOSY

© ISUCT Publishing. Influence of chemical exchange processes on the accuracy of determination of self-diffusion complexes of porphyrinnickel complexes was shown. A method of estimating the inaccuracy of the self-diffusion coefficients for an inverted porphyrin complex was proposed. The values obtained using two different approaches to recording DOSY spectra, STE and CPMG, were compared. Allowing for exchange was shown to be important for accurate diffusion measurements and correct interpretation of results obtained in studied of molecular-level processes

Elacudation of hybrid multi-porphyrin supramolecular assemblies by 2D NMR spectroscopy

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Screening of Conformational Diversity of Molecules of Biologically Active Compouds Based on Nuclear Overhauser Effect Spectroscopy

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Hybrid multi-porphyrin supramolecular assemblies: Synthesis and structure elucidation by 2D DOSY NMR studies

© 2015 Elsevier B.V. All rights reserved. Design and synthesis of hybrid multi-metalloporphyrin assembles have been performed. The chemical structure of the synthesized complexes and their stability in solution were confirmed by the methods of 2D DOSY NMR spectroscopy, which have been specially adapted for these supramolecular architectures in solutions

N-Confused porphyrins: Complexation and¹H NMR studies

© 2017 The Royal Society of Chemistry and the Centre National de la Recherche Scientifique. The complexation of 2-aza-21-carba-tetraphenylporphyrin and 2-aza-2-methyl-5,10,15,20-tetraphenyl-21-carbaporphyrin with nickel and zinc acetates in organic solvents has been investigated by UV-Vis spectroscopy and 1 H NMR. It has been shown that the enhanced reactivity of these tetrapyrrolic macrocycles is mainly determined by their ability to exist in different tautomeric forms

Zinc(II) bis(dipyrromethenate)s crystal solvates with dimethyl sulfoxide Composition, stability and spectral-luminescent properties

© 2017 Elsevier B.V.It was found that 3,3′-, 2,3′ and 2,2′-zinc(II) bis(dipyrromethenate)s ([Zn2L2]) form stable supramolecular complexes of the composition [Zn2L2(DMSO)n] (n = 1 or 2) with dimethyl sulfoxide (DMSO). The [Zn2L2(DMSO)n] are stable in the solid phase and solutions. Composition, stability, and spectral-luminescent properties of the [Zn2L2(DMSO)n] crystal solvates were studied by means of FTIR, PXRD, 1H NMR, DOSY, absorption and fluorescence analyses. Spectroscopic studies showed that the quantum yields (φ) of [Zn2L2(DMSO)n] are lower (to ∼1.6–3.6 times) than quantum yields (φо) of [Zn2L2] in cyclohexane. Quantum-chemical study allowed to suggest the most likely mechanism of the DMSO molecules coordination on the coordinating centers of [Zn2L2]. It is demonstrated, that the high-energy coordination interactions (Zn − O) in [Zn2L2(DMSO)n] are the main cause of the fluorescence quenching of [Zn2L2] in the presence of DMSO. Fluorescence quenching of [Zn2L2] in the DMSO presence is based on the photoinduced electron transfer (PeT) mechanism. The obtained results are interesting for the development of new [Zn2L2] fluorescent sensors of the DMSO molecules

Inversion of population distribution of felodipine conformations at increased concentration in dimethyl sulfoxide is a prerequisite to crystal nucleation

Knowledge of the preferred conformations of biologically active compounds is of the utmost importance for a better understanding of the structure-activity relationships underlying their biological activity, as well as their mechanism of action. Moreover, investigating the mechanism of nucleation from a saturated solution can facilitate the discovery and preparation of new polymorphic forms. To search regularities in the crystal nucleation of biologically active compounds (drugs) from a saturated solution, we studied the conformational preference of felodipine in dilute and saturated solution in dimethyl sulfoxide. The inversion of conformation distribution at increased concentration occurs: conformers that dominate in a dilute solution become the least abundant in the saturated one. Conformers that dominate in the saturated solution are of the same type as revealed in crystalline state by X-ray. © 2014 Wiley Periodicals, Inc. and the American Pharmacists Association J Pharm Sci 103:392-394, 2014