Open AccessHigh-spin binuclear Co(II) complexes with a pendant octaazamaclocycle and carboxylates
Author(s) -
Gordana Vučković,
Slađana Tanasković,
Zoran Miodragović,
Vojislav Stanić
Publication year - 2007
Publication title -
journal of the serbian chemical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.227
H-Index - 45
eISSN - 1820-7421
pISSN - 0352-5139
DOI - 10.2298/jsc0712295v
Subject(s) - cyclam , chemistry , denticity , terephthalic acid , ligand (biochemistry) , molar conductivity , methylene , crystallography , electrochemistry , stereochemistry , tetra , medicinal chemistry , crystal structure , inorganic chemistry , polyester , elemental analysis , organic chemistry , metal , biochemistry , receptor , electrode
Three new binuclear Co(II) mixed-ligand complexes with N,N?,N??,N???-tetrakis( 2-pyridylmethyl)-1,4,8,11-tetraazacyclotetradecane (tpmc) and mono- or dicarboxylate ligands were prepared and some of their physical properties were determined. The general formulas: [Co2(HCOO)2tpmc](ClO4)2?4H2O, [Co2(CH3COO)2tpmc](ClO4)2 and [Co2(tpht)tpmc](ClO4)2?4H2O (tphtH2 = terephthalic acid) were proposed on the basis of elemental analyses (C,H,N) and molar conductivity. UV/Vis absorption and IR spectra, magnetic and CV measurements were used to study their geometries and properties. For the monocarboxylate complexes, an exo coordination of Co(II) with four nitrogens from tpmc and bis-bidentate bonded HCOO-/CH3COO- in the trans position is assumed. Tpmc adopts the chair conformation. For the dicarboxylate complex, it is supposed that a terephthalate dianion, as well as methylene chains from cyclam bridge two Co(II) atoms, while tpmc is in the boat conformation. The complexes were stable against chemical and electrochemical oxidation of Co(II) to Co(III). The data are compared with those for the previously published Cu(II) complexes containing the corresponding ligands and mutual similarities or differences were considered. Finally, some antibacterial activity of the complexes was found.