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Voltammetric and Spectroscopic Behaviour of the Copper Adducts of Thiol and Thioether Ligands under Aerobic and Anaerobic Conditions

Çakir S., Biçer E., Coşkun E., Naumov P., Çakir O.

Polish Journal of Chemistry

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2002

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Vol. 76 / nr 5

663-669

EN

Joint spectroscopic (ESR, electronic absorption and FT IR) and voltammetric (squarewave and cyclic voltammetry) techniques were employed to investigate the properties of copper adducts with cysteine, N-acetylcysteine and methionine under aerobic and anaerobic conditions. The metal oxidation state in the solid and solvated adducts adheres to the presence of oxygen, whereas ESR results (g__ = 2.245, g_ = 2.059,A__= 170 Gauss) reveal tetragonally distorted octahedral copper(II) environment under aerobic circumstances. In presence of the thiol and thioether ligands under nitrogen voltammetric measurements evidence formation of copper(I) species.

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Synthesis and Spectroscopic Studies of the Nicotinamide Adducts of Cobalt(II), Nickel(II) and Zinc(II) Chlorides

Çakir S., Biçer E., Içbudak H., Naumov P., Korkmaz H., Çakir O.

Polish Journal of Chemistry

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2001

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Vol. 75, nr 3

371-377

EN

Nicotinamide (na) adducts of Co(II), Ni(II) and Zn(II) chlorides are synthesized and characterized by thermoanalytical methods (TG, DTG, DTA), FT IR (4000-400 cm-1) and UV/Vis spectroscopy. Structural similarity is inferred between the octahedral Co and Ni compounds of type [M(na)2(H2O)4]Cl2. The tetrahedral Zn complex [Zn(na)2Cl2] presents a different structure. The coordination of the metal ions in the Co and Ni adducts modelled by semiempirical theoretical methods compares well with the structural data for [Ni(na)2(H2O)4](NO3)2_2H2O.

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Spectroscopic and Polarographic Studies of Novel Imidazole Adduct of Ammonium Trioxovanadate(V). A Solution and Solid State Study

Çakir S., Biçer E., Naumov P., Çakir O.

Polish Journal of Chemistry

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2001

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Vol. 75, nr 2

209-214

EN

Complex formation between ammonium trioxovanadate(V) and imidazole has been studied and characterized by FT IR, UV/Vis, thermal analysis (TG, DTA, DTG) and polarographic techniques. Species formed in solid phase yield a yellow coloured product exhibiting an absorbance maximum at 400 nm. The FT IR spectra show that the inclusion of imidazole has a significant influence on the structure and the hydrogen bonding pattern inNH4VO3. Species formed in aqueous solution has been examined by voltammetry. Formation of an adduct of trioxovanadate(V) with imidazole onto dropping mercury electrode followed by reduction of the sample in DCP of the complex in 0.05 M NH3/NH4Cl buffer (pH 9.08) resulted in a single peak at -0.875 V.