EPR and electrochemistry of [NH4]trans-[RuCl4(DMSO)(L)] complexes (L = DMSO, py ). X-ray molecular structure of [pyH][RuCl4(DMSO)(py)]

Paula, Queite A. de; Batista, Alzir A.; Nascimento, Otaciro Rangel; Costa-Filho, Antonio J.; Schultz, Mário Sérgio; Bonfadini, Marcos; Oliva, Glaucius

doi:10.1590/s0103-50532000000500016

Cited by 23 publications

(17 citation statements)

References 14 publications

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“…The difference between the corresponding g --values could be ascribed to the different ligands (Clor solvent) present in the inner coordination sphere. These conclusions were confirmed also by recent literature data for dissolution of Ru(III)-chloride complexes [29] or Ru(III)-mixed ligand complexes with L and Clin DMSO [26]. Here again substitution of Clby DMSO was found, the final product containing two molecules of DMSO.…”

Section: Discussionsupporting

confidence: 89%

“…Its EPR spectrum in the first case shows g -= 2.35 and g || = 1.87, values corresponding completely to the values found by us for D and shown above (2.35 8 and 1.87 9 ). Dissolution in MeOH leads once more to partial substitution of Cland appearance of MeOH in the inner coordination sphere [29]. The substitution of Clby the solvent (both MeOH and DMSO) was proven also directly by X-ray diffraction data.…”

Section: Discussionmentioning

confidence: 78%

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Complexes of Ruthenium (III) with Some 2-Aminothiazole Derivatives

Nikolova

Ivanov²,

Bontchev

et al. 2011

Arzneimittelforschung

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Four new complexes of Ru(III) with a general formula [Ru(L)2Cl2]Cl, where L = 2-amino-4-phenylthiazole (CAS 2010-06-2), 2-amino-4-methylthiazole (CAS 1603-91-4), ethyl 2-amino-4-methyl-5-thiazolecarboxylate (CAS 7210-76-6) and ethyl 2-amino-4-phenyl-5-thiazolecarboxylate (CAS 64399-23-1), were prepared. The syntheses were carried out in polar medium and inert atmosphere at a molar ratio Ru:L = 1:2 or 1:3. The compounds obtained were characterised by IR-, 1H-NMR- 13C-NMR-, UV-VIS-, EPR spectroscopy, magnetochemical and conductivity measurements. The ligands behaved as bidental, bounding Ru(III) through the nitrogen atoms from the amino group and the heterocycle. The complex of ethyl 2-amino-4-phenyl-5-thiazolecarboxylate showed significant antileukaemic activity on various human cells (IC50 values ranging from 20 to 92 micromol/l). Toxicological studies on mice indicated that such concentrations could be reached without mortality. This compound exhibited a promising antineoplastic potential and needs further pharmacological and toxicological evaluation.

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Section: Discussionsupporting

confidence: 89%

Section: Discussionmentioning

confidence: 78%

Complexes of Ruthenium (III) with Some 2-Aminothiazole Derivatives

Nikolova

Ivanov²,

Bontchev

et al. 2011

Arzneimittelforschung

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“…This is a consequence of the linear (cylindrical π-bonding) binding of CO ligand to osmium. Axial EPR spectra are also seen for complexes of type trans -[RuCl 4 (L)(Me 2 SO)] − , where L = Me 2 SO 80 or various azole ligands, e.g., pyrazole, as well as pyridine. 81 The key point, however, is not that whether a (Ru,Os) III species exhibits a rhombic or axial spectrum, but whether g ║ (i.e., the unique feature) is greater (at lower resonant magnetic field) or less (at higher field) than g ⊥ (averaging a rhombic signal if necessary).…”

Section: Resultsmentioning

confidence: 95%

“…The g values presented are all for complexes with tetraethylammonium countercation; for trans -Cs[OsCl 4 (CO)(py)]: g ⊥ = 2.46, g ║ = 1.45. c Taken from Ni Dhubhghaill et al 82 d Taken from de Paula et al 80 The g values reported are for the solid material; in aqueous or methanol solution, multiple species are reported due to replacement of Me 2 SO and/or chlorido ligands by solvent. e Taken from Clarke et al 77 The values for | g min | were not observed (hence they are given in parentheses), but were proposed by their LFT analysis. In these systems, the proper choice of sign of the g values is not apparent based on standard criteria, namely the magnitudes of k or Δ, so both choices are given.…”

Section: Figurementioning

confidence: 99%

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cis-Tetrachlorido-bis(indazole)osmium(iv) and its osmium(iii) analogues: paving the way towards the cis-isomer of the ruthenium anticancer drugs KP1019 and/or NKP1339

et al. 2017

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The relationship between cis-trans isomerism and anticancer activity has been mainly addressed for square-planar metal complexes, in particular, for platinum(II), e.g., cis- and trans-[PtCl2(NH3)2], and a number of related compounds, of which, however, only cis-counterparts are in clinical use today. For octahedral metal complexes, this effect of geometrical isomerism on anticancer activity has not been investigated systematically, mainly because the relevant isomers are still unavailable. An example of such an octahedral complex is trans-[RuCl4(Hind)2]−, which is in clinical trials now as its indazolium (KP1019) or sodium salt (NKP1339), but the corresponding cis-isomers remain inaccessible. We report the synthesis of Na[cis-OsIIICl4(κN2-1H-ind)2] (Na[1]) to show that cis-isomer of NKP1339 can in principle be prepared as well. The procedure involves heating (H2ind)[OsIVCl5(κN1-2H-ind)] in a high boiling point organic solvent resulting in an Anderson rearrangement with formation of cis-[OsIVCl4(κN2-1H-ind)2] ([1]) in high yield. The transformation is accompanied by an indazole coordination mode switch from κN1 to κN2 and stabilization of the 1H-indazole tautomer. Fully reversible spectroelectrochemical reduction of [1] in acetonitrile at 0.46 V vs NHE is accompanied by a change in electronic absorption bands indicating formation of cis-[OsIIICl4(κN2-1H-ind)2]− ([1]−). Chemical reduction of [1] in methanol with NaBH4 followed by addition of nBu4NCl afforded the osmium(III) complex nBu4N[cis-OsIIICl4(κN2-1H-ind)2] (nBu4N[1]). Metathesis reaction of nBu4N[1] with an ion exchange resin led to isolation of the water-soluble salt Na[1]. The X-ray diffraction crystal structure of [1]·Me2CO was determined and compared with that of trans-[OsIVCl4(κN2-1H-ind)]·2Me2SO (2·2Me2SO), also prepared in this work. EPR spectroscopy was performed on the OsIII complexes and the results analyzed by ligand-field and quantum chemical theories. We furthermore assayed effects of [1] and Na[1] on cell viability and proliferation in comparison to trans-[OsIVCl4(κN1-2H-ind)] [3] and cisplatin and found a strong reduction of cell viability at concentrations between 30 and 300 µM in different cancer cell lines (HT29, H446, 4T1 and HEK293). HT-29 cells are less sensitive to cisplatin than 4T1 cells, but more sensitive to [1] and Na[1], as shown by decreased proliferation and viability as well as an increased late apoptotic/necrotic cell population.

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One‐Electron Reduction of Acenaphthene‐1,2‐Diimine Nickel(II) Complexes

Khrizanforova

Fayzullin

Морозов

et al. 2019

Chemistry An Asian Journal

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New nickel‐based complexes of 1,2‐bis[(2,6‐diisopropylphenyl)imino]acenaphthene (dpp‐bian) with BF4− counterion or halide co‐ligands were synthesized in THF and MeCN. The nickel(I) complexes were obtained by using two approaches: 1) electrochemical reduction of the corresponding nickel(II) precursors; and 2) a chemical comproportionation reaction. The structural features and redox properties of these complexes were investigated by using single‐crystal X‐ray diffraction (XRD), cyclic voltammetry (CV), and electron paramagnetic resonance (EPR) and UV/Vis spectroscopy. The influence of temperature and solvent on the structure of the nickel(I) complexes was studied in detail, and an uncommon reversible solvent‐induced monomer/dimer transformation was observed. In the case of the fluoride complex, the unpaired electron was found to be localized on the dpp‐bian ligand, whereas all of the other nickel complexes contained neutral dpp‐bian moieties.

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EPR and electrochemistry of [NH4]trans-[RuCl4(DMSO)(L)] complexes (L = DMSO, py ). X-ray molecular structure of [pyH][RuCl4(DMSO)(py)]

Cited by 23 publications

References 14 publications

Complexes of Ruthenium (III) with Some 2-Aminothiazole Derivatives

Complexes of Ruthenium (III) with Some 2-Aminothiazole Derivatives

cis-Tetrachlorido-bis(indazole)osmium(iv) and its osmium(iii) analogues: paving the way towards the cis-isomer of the ruthenium anticancer drugs KP1019 and/or NKP1339

One‐Electron Reduction of Acenaphthene‐1,2‐Diimine Nickel(II) Complexes

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