Naslov
In situ Co(II) oxidation upon coordination to the dithiocarbamate derivative

Autori
Višnjevac, Aleksandar ; Vojta, Danijela ; Kosović, Milica ; Đaković, Marijana ; Leka, Zorica

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
28th European Crystallographic Meeting - Book of abstracts, Acta Cryst (2013) A69 / - Warwick : University of Warwick, 2013, S633-s633

Skup
28th European Crystallographic Meeting

Mjesto i datum
Warwick, Ujedinjeno Kraljevstvo, 25.08.2013. - 29.08.2013

Vrsta sudjelovanja
Poster

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
dithiocarbamates ; cobalt coordination ; fungicides

Sažetak
Dithiocarbamate derivatives, besides other industrial applications, are used for many years now as powerful fungicides and pesticides.[ ] Complexes of Co(II) and Co(III) with our, previously reported, biologically active ligand, N, N-diacetato-N-dithiocarbamate (dadtc3-) (1) [ ] were prepared and characterized by classical physico-chemical methods, with the aim of enhancing the already intriguing fungicidal activity of the ligand itself. Anionic Co(II) complex [Co2(H2dadtc)5](2), obtained by a simple addition of the acidic ligand solution to the aqueous solution of [Co(H2O)6]Cl2 at RT, undergoes, in presence of air, over several days, spontaneous Co(II) oxidation to the Co(III) state, followed by an overall chemical rearrangement, resulting in the formation of the molecular Co(III) complex 3. Complex 2 reveals a binuclear structure where two hexacoordinated cobalt(II) centres (CoA and CoB) are presumably double- bridged by two sulfur atoms from two ligand molecules. Remaining two sulfurs of these ligand molecules both coordinate the CoB centre. Its octahedral coordination sphere is completed by two sulfurs from the CSS group of the third ligand molecule. CoA is also bound to four sulfurs from remaining two ligand molecules. Formation of the anionic species (2) was undoubtly proven by MALDI- TOFF analysis. Magnetic measurements revealed a strong antiferromagnetic coupling of two neighbouring paramagnetic Co(II) centres, suggesting the double bridged arrangement as described here and by others.[ ] The elemental analysis is in a very good agreement with NH4+ as a counterion, giving a reliable proof that the cobalt ions are not oxidized to the Co(III) state at this point. The structure of the Co(III) complex (3) reveals a neutral mononuclear complex molecule with a hexacoordinated cobalt(III) centre of a molecular formula [Co(dadtc)3]. It crystallizes in orthorhombic space group Pnna, with four molecules per unit cell, a = 10.1024 (3) Å, b = 18.9591 (7) Å, c = 16.9287 (5) Å. Co(III) lies at the twofold rotation axis, and is in the centre of a significantly distorted octahedron formed by six sulfur atoms from three CSS groups belonging to three ligand molecules.

Izvorni jezik
Engleski

Znanstvena područja
Kemija

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