Evolution of the Structural Parameters and Magnetic Properties in a Series of Di(μ-hydroxy)bis(nitrilotriacetato)dichromium(III) Complexes

• Published in: European Journal of Inorganic Chemistry 2005-03, Vol.2005 (5), p.929-937
• Main Authors: Novitchi, Ghenadie, Costes, Jean-Pierre, Ciornea, Victor, Shova, Sergiu, Filippova, Irina, Simonov, Yurii A., Gulea, Aurelian
• Format: Article
• Language: English
• Subjects: Alkaline earth metals; Chromium; Magnetic properties; N,O ligands; O ligands
• ISSN: 1434-1948; 1099-0682
• DOI: 10.1002/ejic.200400949

Four heterometallic complexes {Mg(H2O)6}[Cr2(μ‐OH)2‐(nta)2]·4 H2O (I), {Ca(H2O)3}[Cr2(μ‐OH)2(nta)2]·3 H2O (II), {Sr(H2O)3}[Cr2(μ‐OH)2(nta)2]·3 H2O (III) and {Ba(H2O)3‐dmso}[Cr2(μ‐OH)2(nta)2]·2 H2O (IV) containing dinuclear bis(μ‐hydroxo) chromium(III) complex ions, where nta is the nitrilotriacetate ligand and dmso is dimethyl sulfoxide, have been prepared and crystallographically characterised. Compound I displays an ionic type structure, II and III are 3D coordination polymers and IV behaves like a 2D coordination polymer. In these compounds, the chromium(III) dimeric unit exhibits different structural features. It forms a polymeric structure by coordination of alkaline earth metal ions and/or formation of hydrogen‐bonding interactions. The temperature dependencies of the magnetic susceptibilities of I–IV were fitted on the basis of the expression derived from the isotropic Hamiltonian including a biquadratic exchangeterm, Ĥ = –2J(1 2) – j(1 2)2. The values of the coupling interaction (J) range from –17.38 cm–1 to –5.80 cm–1 and the biquadratic terms (j) from +0.71 to 2.02 cm–1. The experimental and theoretical values of J (calculated, using the Glerup–Hodgson–Pedersen model) have been discussed. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)