A Case Study on the Resolution of the 1-i-Butyl-3-methyl-3-phospholene 1-Oxide via Diastereomeric Complex Formation Using TADDOL Derivatives and via Diastereomeric Coordination Complexes Formed from the Calcium Salts ofO,O′-Diaroyl-(2R,3R)-tartaric Acids

The synthesis and crystal structures of bis-N-(2,5-dimethoxyphenyl)pyridine-2,6-dicarbothioamide (dicarbothioamide I) and 6-(4,7-dimethoxy-2-benzothiazolyl)-N-(2,5-dimethoxyphenyl)-2-pyridinecarbothioamide (L1) as well as the syntheses of the palladium(ii) chloride and acetate pincer complexes are reported. The stability constant for the palladium complex formation at 25°C was found to be (2.04 ± 0.26) × 104 dm3 mol–1 and (2.30 ± 0.19) × 104 dm3 mol–1 with ΔfH = 8 ± 1 kJ mol–1, ΔfSθ = 108 ± 10 J K–1 mol–1, and ΔfH = 17 ± 4 kJ mol–1 and ΔfSθ = 140 ± 20 J K–1 mol–1 for the PdClL1 and Pd(OAc)L1, respectively. The kinetics of formation of the palladium(ii) complexes were investigated and the mechanism is proposed to be associative in nature (ΔH1‡ = 34 ± 2 kJ mol–1 and ΔS1‡ = –113 ± 8 J K–1 mol–1, and ΔH1‡ = 37 ± 3 kJ mol–1 and ΔS1‡ = –100 ± 8 J K–1 mol–1 for the PdClL1 and Pd(OAc)L1 species, respectively). The electrochemical measurements of the acetonitrile solutions revealed irreversible electron transfers consistent with the electrochemical decomposition of the ligand and its coordination complexes.

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Coordination Complex Formation and Redox Properties of Kynurenic and Xanthurenic Acid Can Affect Brain Tissue Homeodynamics

Antioxidants ◽

10.3390/antiox8100476 ◽

2019 ◽

Vol 8 (10) ◽

pp. 476 ◽

Cited By ~ 6

Author(s):

Lenka Kubicova ◽

Franz Hadacek ◽

Gert Bachmann ◽

Wolfram Weckwerth ◽

Vladimir Chobot

Keyword(s):

Complex Formation ◽

Neurodegenerative Diseases ◽

Antioxidant Activities ◽

Differential Pulse ◽

Coordination Complexes ◽

Kynurenine Pathway ◽

Coordination Complex ◽

Xanthurenic Acid ◽

Ros Scavenging ◽

Deoxyribose Degradation

Reactive oxygen species (ROS) are known for their participation in various physiological and pathological processes in organisms, including ageing or degeneration. Kynurenine pathway metabolites, such as kynurenic (KYNA) or xanthurenic (XA) acid, can affect neurodegenerative diseases due to their ROS scavenging and Fe ion coordination complex formation but insights are still incomplete. Therefore, we investigated the formation and antioxidant capabilities of KYNA– and XA–Fe complexes by nano-electrospray−mass spectrometry, differential pulse voltammetry, deoxyribose degradation and FeII autoxidation assays. XA formed coordination complexes with FeII or FeIII ions and was an effective antioxidant. By contrast, only FeII–KYNA complexes could be detected. Moreover, KYNA showed no antioxidant effects in the FeCl3/ascorbic acid deoxyribose degradation assay variant and only negligible activities in the FeII autoxidation assay. Coordination complexes of Fe ions with KYNA probably stabilize KYNA in its keto tautomer form. Nevertheless, both KYNA and XA exhibited sufficient antioxidant activities in some of the employed assay variants. The results provide evidence that both have the potential to alleviate neurodegenerative diseases by helping to maintain tissue redox homeodynamics.

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Organophosphoryl complexes of zirconium tetrachloride

Australian Journal of Chemistry ◽

10.1071/ch9692295 ◽

1969 ◽

Vol 22 (11) ◽

pp. 2295 ◽

Cited By ~ 5

Author(s):

B Kautzner ◽

PC Wailes

Keyword(s):

Complex Formation ◽

Phosphorus Atom ◽

Coordination Complexes ◽

Zirconium Tetrachloride

A number of coordination complexes of zirconium tetrachloride with phosphoryl ligands of the type (RO)3PO, (RO)2P(O)R?, ROP(O)R?2, and R3PO have been prepared and characterized as complexes of the type ZrCl4,2L. The shifts of the phosphoryl stretching frequency in the infrared on complex formation have been measured and are discussed with reference to the electronegativity of the substituents on the phosphorus atom.

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