Structure of 3,4-dihydroxy-trans-cinnamic acid (caffeic acid) and its lack of solid-state topochemical reactivity

García-Granda, S.; Beurskens, Gezina; Beurskens, P. T.; Krishna, Tallapragada S. R.; Desiraju, Gautam R.

doi:10.1107/s0108270187094526

Cited by 25 publications

(22 citation statements)

References 4 publications

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“…Table 1 comprises the optimised geometries for the lowest energy conformers found for CA. These structural parameters do not deviate much from the X-ray values found in the literature for caffeic acid [36] (although comparison between results in the solid and in the gas phase must be done with care). Moreover, the values presently obtained for the most stable conformer, CA 1, are in very good accordance with the ones reported by Bakalbassis et al, for the only ground-state geometry calculated by these authors for caffeic acid, at both the HF/6-31 þ G* and B3LYP/6-31 þ G* levels [18].…”

Section: Resultssupporting

confidence: 47%

Ab initio conformational study of caffeic acid

VanBesien

Marques

2003

Journal of Molecular Structure: THEOCHEM

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A complete conformational analysis of caffeic acid, a phenolic derivative with well known antioxidant properties, was carried out by ab initio calculations, at the density funtional theory (DFT) level. Fourteen different conformers were obtained, the most stable ones being planar, as the conformational preferences of this molecule were found to be mainly determined by the stabilising effect of p-electron delocalisation. Harmonic vibrational frequencies, as well as potential energy profiles for rotation around several bonds within the molecule, were also calculated. q

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Section: Resultssupporting

confidence: 47%

Ab initio conformational study of caffeic acid

VanBesien

Marques

2003

Journal of Molecular Structure: THEOCHEM

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“…All tables with the structural data for all acids and phenoxyl radicals under examination are given as Supplementary Material (Tables S1-S5), available upon request from the author. Owing to the lack of structural experimental studies in the gas phase for the same acids, the X-ray solid-state ones for caffeic (23) and ferulic (24) acids are also given in Table S1. Although comparison between results in the gas and the solid state is not allowed, it is simply mentioned that the corresponding values do not deviate more than 1%.…”

Section: Resultsmentioning

confidence: 99%

“…Neither structural nor detailed frequency data were given in that paper. The only experimental data available for the four acids under study are solid-state X-ray crystallographic studies for caffeic and ferulic acids (23,24) and solidstate infrared spectroscopic data for all of them (25).…”

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confidence: 99%

Ab initio and density functional theory studies for the explanation of the antioxidant activity of certain phenolic acids

Bakalbassis

Chatzopoulou

Melissas

et al. 2001

Lipids

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Ab initio and density functional theory molecular orbital calculations were carried out at both the HF/6-31 +G(d) and B3LYP/6-31+G(d) levels for the four antioxidants, p-hydroxycinnamic acid derivatives, namely, the p-coumaric, caffeic, ferulic, and sinapinic acid and the corresponding radicals, in an attempt to explain the structural dependency of the antioxidant activity of these compounds. Optimized resulting geometries, vibrational frequencies, absolute infrared intensities, and electron-donating ability are discussed. Both the high degree of conjugation and the extended spin delocalization in the phenoxyl radicals offer explanation for the scavenging activity of the four acids. In structurally related compounds, the calculated heat of formation value in radical formation appears as a meaningful molecular descriptor of antioxidant activity in accordance with experimental data. This becomes more clear at the B3LYP level.

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“…The hydrogen coupling constants were calculated using the MacConnell relation, a H = Q CH r(C), where Q CH is the MacConnell constant (Q CH = 25 G) and r(C) is the spin density of the carbon linked to the given hydrogen. The propenoic acid moiety presents a diedral angle of 20°versus the aromatic ring, 22 but we used an angle of 30°as previously used by Dixon et al 14 Calculations were performed for each molecule with the nitro group rotated out of the plane of the ring, in steps of 10°for the deformed geometry (i.e. a twisted angle between the plane of the ring and the nitro group) and are depicted in Fig.…”

Section: Free Radical Formationmentioning

confidence: 99%