کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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1308732 | 975180 | 2009 | 11 صفحه PDF | دانلود رایگان |

Cobalt complexes of 3- and 6-methylpicolinic acid, namely [Co(3-Mepic)3] (1) and [Co(6-Mepic)2(H2O)2] · 2H2O (2) were prepared and characterized by spectroscopic methods (IR, UV–Vis, NMR), their molecular and crystal structures were determined by X-ray crystal structure analysis and their thermal stability by TGA/DTA methods. Square-wave voltammetry showed that on mercury electrode the oxidation of 2 requires higher potential than the oxidation of complex anion [Co(3-Mepic)3]−, the most probable product of the reduction of 1. The reduction of 1 and the oxidation of 2 depend on the kinetics of electron transfer and the electrode material. X-ray structural analysis revealed octahedral coordination polyhedron in both 1 and 2 and the same N,O-chelated coordination mode for both ligands. 13C, 1H and 15N NMR spectroscopy confirmed that coordination mode of 3-methylpicolinic acid in 1 in DMSO solution. UV–Vis spectrophotometric measurements were used to study the complexation of cobalt with 3- and 6-methylpicolinic acid in aqueous solution and to determine the composition of the formed complexes by Job method of continuous variation. The stoichiometry of the complex with 3-methylpicolinic acid is 2:3, while it is 2:3 and 3:2 for the complex with 6-methylpicolinic acid, indicating the possibility of the formation of more than one complex species.
Two cobalt complexes with 3- and 6-methylpicolinic acid were prepared and characterized by spectroscopic and thermal methods, while their crystal structures were determined by X-ray structural analysis. Complexes were studied by voltammetric methods and their formation and composition were determined by spectrophotometric measurements in solution.Figure optionsDownload as PowerPoint slide
Journal: Inorganica Chimica Acta - Volume 362, Issue 8, 1 June 2009, Pages 2704–2714