M. Vaira, F. Mani
1983
Citations
0
Influential Citations
11
Citations
Journal
Inorganica Chimica Acta
Abstract
Abstract Cobalt(II) complexes with the tetradentate ligand tris(1-pyrazolylethyl)amine, TPyEA, and a variety of co-ligands have been synthesized and characterized. The complexes with general formula [CoX(TPyEA)]BPh4 are mononuclear and five-coordinate when X = NCS, NCO, I, ClO4, or dinuclear with six-coordinate metal centers when X = F, Cl, Br, N3. The structure of the dinuclear bromo derivative has been determined by X-ray analysis. Each cobalt atom in the dinuclear [CoBr(TPyEA)]2+2 cation is coordinated by the four nitrogen donor atoms of the TPyEA ligand and by the two bridging bromine atoms in a distorted octahedral geometry. The dinuclear complexes are reversibly converted in the solid state to mononuclear five-coordinate species by heating or grinding. The same dissociation occurs upon dissolution in acetone. The complexes with bidentate co-ligands, [CoY(TPyEA)]BPh4 (Y = 2-mercaptobenzoate), [CoY(TPyEA)] ClO4 (Y = acetylacetonate, benzoylacetonate), and [Co(NCS)2(TPyEA)] are six-coordinate. Also the above six-coordinate bis thiocyanate complex undergoes a transformation upon dissolution or grinding.