Die Kristallstruktur von Brenzcatechin: eine Neubestimmung

Wunderlich, H.; Mootz, D.

doi:10.1107/s0567740871004618

Cited by 82 publications

(25 citation statements)

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“…Therefore, it is necessary to examine the crystal polymorphism of the products obtained from different solutions. As illustrated in Figure 2, the catechol products crystallized from isopropanol, methyl acetate and ethyl acetate have similar characteristic peaks with the raw material, proving that all the samples were in the same crystal form as reported [43]. In addition, the simulated powder X-ray diffraction (PXRD) pattern of the catechol obtained from CSD was consistent with the patterns of the experimental crystals (Supplementary Materials Figure S1).…”

Section: Polymorph Identificationsupporting

confidence: 74%

Solvent Effects on Catechol Crystal Habits and Aspect Ratios: A Combination of Experiments and Molecular Dynamics Simulation Study

et al. 2020

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This work could help to better understand the solvent effects on crystal habits and aspect ratio changes at the molecular level, which provide some guidance for solvent selection in industrial crystallization processes. With the catechol crystal habits acquired using both experimental and simulation methods in isopropanol, methyl acetate and ethyl acetate, solvent effects on crystal morphology were explored based on the modified attachment energy model. Firstly, morphologically dominant crystal faces were obtained with the predicted crystal habit in vacuum. Then, modified attachment energies were calculated by the molecular dynamics simulation to modify the crystal shapes in a real solvent environment, and the simulation results were in agreement with the experimental ones. Meanwhile, the surface properties such as roughness and the diffusion coefficient were introduced to analyze the solvent adsorption behaviors and the radial distribution function curves were generated to distinguish diverse types of interactions like hydrogen bonds and van der Waals forces. Results show that the catechol crystal habits were affected by the combination of the attachment energy, surface structures and molecular interaction types. Moreover, the changing aspect ratios of catechol crystals are closely related to the existence of hydrogen bonds which contribute to growth inhibition on specific faces.

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Section: Polymorph Identificationsupporting

confidence: 74%

Solvent Effects on Catechol Crystal Habits and Aspect Ratios: A Combination of Experiments and Molecular Dynamics Simulation Study

et al. 2020

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“…This clearly indicates that both ligands 27 and 28 are catecholates; the charge on 28 is higher (in absolute value) than that on 27 owing to the higher electronegativity of ligand 28 (a tetrachloro-ocatechol is more electronegative than an o-catechol). The same observations can be applied to the cases of ligands 29 and 30, which have A values significantly lower than -2 [ -2.29( 13) and -2.1 7( 8) respectively] and are more electronegative than the other ligands bonded to the phosphorus(v) centre (oaminophenol and N-methyl-o-amin~phenol).~~ Ligand 11 1 was described as a semiquinonate chelated to an indium(II1) ion in the complex [1nL2Br2(4Me-py),] (4Me-py = 4-meth~lpyridine).~~ For this ligand we found a A value of -0.57 (15), significantly different from -1, indicating that it is intermediate between the semiquinonate and benzoquinone limiting forms. Therefore, there is a partial electron transfer from the quinone to the InBr2(4Me-py), moiety.…”

Section: Resultsmentioning

confidence: 92%

Ligands derived from o-benzoquinone: statistical correlation between oxidation state and structural features

Carugo¹,

Castellani²,

Djinović³

et al. 1992

J. Chem. Soc., Dalton Trans.

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“… a The geometry of catechol from combined microwave spectroscopy and 4‐21G* ab initio calculation 30. …”

Section: Resultsmentioning

confidence: 99%

Local atomic and orbital reactivity indices from density functional calculations for hydrogen-bonded 1,2-dihydroxybenzene

Vedernikova

Proynov

Salahub

et al. 2000

Int. J. Quant. Chem.

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ABSTRACT:The Kohn᎐Sham LCGTO᎐DFT program deMon-KS3 was used to calculate the geometry, the electronic structure, and the local charge fluctuations in catechol as a model for substituted flavonoids with an internal hydrogen bond. The results bring some new insight into the nature of internal hydrogen bonding and its role in radical stabilization. Particular attention is paid to the effect of the hyperconjugation inherent to these systems. The relative strength of the intramolecular hydrogen bond is about 3.62 kcalrmol in the neutral state, decreases to about 1.42 kcalrmol in the cation radical form, and, remarkably, increases to about 8.9 kcalrmol in the radical formed by proton loss. The hydrogen-bonded oxygen atom shows a larger degree of electron localization in terms of the local charge᎐charge fluctuations compared to the oxygen without a hydrogen bond. The concept of orbital hardness indices was used to describe in more detail the interrelationship between internal hydrogen bonding and stabilization of neutral or charged radicals. These trends reflect the effect of hyperconjugation in terms of

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Die Kristallstruktur von Brenzcatechin: eine Neubestimmung

Cited by 82 publications

References 0 publications

Solvent Effects on Catechol Crystal Habits and Aspect Ratios: A Combination of Experiments and Molecular Dynamics Simulation Study

Solvent Effects on Catechol Crystal Habits and Aspect Ratios: A Combination of Experiments and Molecular Dynamics Simulation Study

Ligands derived from o-benzoquinone: statistical correlation between oxidation state and structural features

Local atomic and orbital reactivity indices from density functional calculations for hydrogen-bonded 1,2-dihydroxybenzene

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