Voltammetric and Theoretical Study of the Redox Properties of Rubrolide Analogues

Varejão, Jodieh O. S.; Barbosa, Luiz C. A.; Maltha, Célia R. A.; Lage, Mateus R.; Lanznaster, Maurício; Carneiro, José Walkimar de M.; Forlani, Giuseppe

doi:10.1016/j.electacta.2013.12.053

Cited by 17 publications

(11 citation statements)

References 37 publications

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“…This interpretation corroborates with the more negative potential for Co 3+ /Co 2+ reduction in complex 2. [32,42,43] To evaluate the energies involved in the hypothetical Co 3+ /Co 2+ reduction associated with ligand dissociation, calculations were also performed for the reduced complexes [Co II (TPA)(TCC)] and [Co II (py 2 en)(TCC)] and the corresponding species generated after dissociation of the TCC ligand. Since two distinct spin multiplicities are expected for Co 2+ , S = 3/2 for t 2 g 5 eg 2 (HS) and S = 1 / 2 for t 2 g 6 eg 1 (LS), the spin density was calculated for both high and low-spin configurations.…”

Section: Resultsmentioning

confidence: 99%

Investigation of Cobalt(III)‐Tetrachlorocatechol Complexes as Models for Catechol‐Based Anticancer Prodrugs

et al. 2019

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Two novel cobalt(III) complexes, [Co(TPA)(TCC)]ClO4·H2O (1) and [Co(py2en)(TCC)]ClO4·2H2O (2), were synthesized and fully characterized by IR, UV/Vis and 1H NMR spectroscopy, ESI mass spectrometry, and X‐ray diffraction. Cyclic voltammetry experiments revealed an irreversible reduction of the Co3+ center for both complexes. The Co3+/Co2+ redox potential, –0.91 V for 1 and –1.15 V for 2 (vs. Fc/Fc+), was obtained by square wave voltammetry in DMSO. Reactions of 1 and 2 with ascorbic acid and sodium dithionite at pH 7.4 and 6.2 were carried out in argon and open‐air atmospheres, to simulate biological redox activation under hypoxia and normoxia. Neither the Co3+/Co2+ reduction nor the dissociation of TCC2– was observed. Thermodynamic parameters calculated for the Co3+/Co2+ reduction and substitution of the TCC2– ligand by water indicate an endothermic non‐spontaneous reaction.

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Section: Resultsmentioning

confidence: 99%

Investigation of Cobalt(III)‐Tetrachlorocatechol Complexes as Models for Catechol‐Based Anticancer Prodrugs

et al. 2019

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“…In photosynthetic organisms, plastoquinones play a central role in carrying electrons from photosystem (PS) II to the cytochrome b6f complex. To verify whether the phytotoxic activity of aminoquinones may depend on their ability to inhibit the chloroplastic electron transport, the light‐driven reduction of ferricyanide by isolated thylakoid membranes, the so‐called Hill reaction, was measured in the absence or in the presence of a given 2,5‐bis(alkyamino)‐1,4‐benzoquinone, as previously described ( Fig. ).…”

Section: Resultsmentioning

confidence: 99%

“…Molecular attributes analyzed (clog P ( P = octan‐1‐ol/H 2 O partition coefficient), the molecular weight (MW), the amount of H‐bond donors (HBD), the amount of H‐bond acceptor (HBA), and the number of rotable bonds (nRotb)) were calculated using the software provided by Molinspirations Cheminformatics (Bratislava, Slovak Republic, http://www.molinspiration.com), whereas log S (solubility in H 2 O, g/l) was calculated using the OSIRIS software .…”

Section: Experimental Partmentioning

confidence: 99%

Amino‐substituted para‐Benzoquinones as Potential Herbicides

Nain-Pérez

Barbosa

Picanço

et al. 2016

Chemistry & Biodiversity

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Although quinones present a large array of biological activities, a few studies on the herbicidal potential of 2,5-bis(alkyl/arylamino)-1,4-benzoquinones have been reported to date. In this work, starting from benzoquinone, 13 2,5-bis(alkyl/arylamino)-1,4-benzoquinones were prepared in 46 - 93% yield. The products were fully characterized by spectroscopic analyses and their phytotoxicity against Cucumis sativus and Sorghum bicolor seedlings was investigated. At 100 ppm, compounds caused 10 - 88% growth inhibition of the dicotyledonous species, whereas the monocotyledon was less affected. Most compounds exerted little inhibitory effect on a cyanobacterial model strain. However, at 100 μm, compounds 8 - 10 caused about 50% inhibition of algal growth, and compounds 1 and 2 reduced cell viability in the 1 - 10 μm range. The ability of benzoquinone derivatives to interfere with the light-driven ferricyanide reduction by isolated spinach chloroplasts was evaluated. Some substances showed a moderate effect as uncouplers, but no relationship was found between this property and their biological activity, indicating that the herbicidal effect is not associated with the inhibition of the photosynthetic electron transport chain. Phytotoxic compounds were not toxic to insects, strengthening the possibility that they may serve as lead for the development of eco-friendly herbicides.

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“…Moreover, a voltammetric study of rubrolide analogues showed the possibility of these compounds to act as hydrogen acceptor at photosystem I, being reduced in the process. 45 More recently, Teixeira et al 18 proposed a photoelectron transfer to the herbicide via His215, forming a radical anion. Based on these results and the QMafYY descriptor, it is reasonable to propose a similar photoelectron transfer to the nostoclide analogues via a hydrogen bond interaction with the oxygen O13, which is favored by an electron deficiency at the atom in position R 3 .…”

Section: Analysis Of the Selected Molecular Descriptorsmentioning

confidence: 99%

2D, 3D and Hybrid QSAR Studies of Nostoclide Analogues as Inhibitors of the Photosystem II

Ferreira¹

2018

J. Braz. Chem. Soc.

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Synthetic herbicides are widely used for weed control in crops. Continuous application of chemicals induces the adaptation of weeds, leading to the development of resistance. Therefore, research for novel synthetic herbicides plays an important role in crop protection and food production. Within this context, it is important to understand the relationship between the structures of a set of compounds endowed with herbicide activity and their biological response. In this work, a quantitative structure-activity relationship (QSAR) study of 34 nostoclide analogues was carried out in order to analyze their ability to inhibit the photosystem-II. Compounds were optimized using the DFT/B3LYP/Def2-TZVPP method. 2D and 3D (Lennard-Jones and electrostatic potential energies) molecular descriptors were calculated at the same theory level. QSAR models showed major importance of electrostatic ligand-acceptor interactions and indicated the presence of aromatic interaction in the benzyl group. A photoelectron transfer via hydrogen-bond was proposed to occur between His215 residue and the carbonyl group.

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Voltammetric and Theoretical Study of the Redox Properties of Rubrolide Analogues

Cited by 17 publications

References 37 publications

Investigation of Cobalt(III)‐Tetrachlorocatechol Complexes as Models for Catechol‐Based Anticancer Prodrugs

Investigation of Cobalt(III)‐Tetrachlorocatechol Complexes as Models for Catechol‐Based Anticancer Prodrugs

Amino‐substituted para‐Benzoquinones as Potential Herbicides

2D, 3D and Hybrid QSAR Studies of Nostoclide Analogues as Inhibitors of the Photosystem II

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