Details

Autor(en) / Beteiligte

• Ovcharenko, V. I.
• Fokin, S. V.
• Romanenko, G. V.
• Ikorskii, V. N.
• Reznikov, V. A.
• Podoplelov, A. V.

Titel

Complexes of metals with paramagnetic 3-Imidazoline schiff bases

Ist Teil von

• Journal of structural chemistry, 1997-07, Vol.38 (4), p.626-636

Ort / Verlag

New York: Springer Nature B.V

Erscheinungsjahr

1997

Quelle

SpringerLINK Contemporary (Konsortium Baden-Württemberg)

Beschreibungen/Notizen

• Methods for the synthesis of intracomplex bischelates CuL2, NiL2, CoL2, and the mixed- ligand complex NiL2y2, where L is a deprotonated derivative of the stable nitroxide 4- (2′- hydroxyphenyl)- 2,2,5,5tetramethyl- 3- imidazoline- 1-oxyl, were developed. In the solid state, the compounds have a molecular structure. The most significant difference in the structure of ML2 molecules lies in the values of the angle between the chelate rings (56.9‡ for CuL2, 78.8‡ for CoL2, and 0‡ for NiL2. In complexes with paramagnetic metal ions, the intramolecular exchange interactions are ferromagnetic in character and are close in the order of magnitude (5.7 cm− 1 for CuL2 and 6.8 cm− for NiL2Py2) to the values for complexes with deprotonated enaminoketone derivatives of 3- imidazoline. The NiL2 molecules, having a square coordination of the central atom, are biradicals with antiferromagnetic exchange interactions between the unpaired electrons of nitroxyl groups (− 3.6 cm−). The transformation of NiL2 into NiL2Py2 leads to a transition of Ni(II) from the low- to high- spin state and to ferromagnetic exchange between the unpaired electrons of the paramagnetic centers.