Structural and EPR Studies on Single-Crystal and Polycrystalline Samples of Copper(II) and Cobalt(II) Complexes with N2S2-Based Macrocyclic Ligands

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• 作者：Abel Tamayo ; Jaume Casabó ; Lluí ; s Escriche ; Pablo Gonz&aacute ; lez ; Carlos Lodeiro ; Alberto C. Rizzi ; Carlos D. Brondino ; M. C. G. Passeggi ; Raikko Kivekä ; s ; Reijo Sillanpä ; ä
• 刊名：Inorganic Chemistry
• 出版年：2007
• 出版时间：July 9, 2007
• 年：2007
• 卷：46
• 期：14
• 页码：5665 - 5672
• 全文大小：200K
• 年卷期：v.46,no.14(July 9, 2007)
• ISSN：1520-510X

文摘

The properties of Cu(II) and Co(II) complexes with oxygen- or nitrogen-containing macrocycles have been extensivelystudied; however, less attention has been paid to the study of complexes containing sulfur atoms in the firstcoordination sphere. Herein we present the interaction between these two metal ions and two macrocyclic ligandswith N₂S₂ donor sets. Cu(II) and Co(II) complexes with the pyridine-containing 14-membered macrocycles 3,11-dithia-7,17-diazabicyclo[11.3.1]heptadeca-1(17),13,15-triene (L) and 7-(9-anthracenylmethyl)-3,11-dithia-7,17-diazabicyclo[11.3.1]heptadeca-1(17),13,15-triene (L1) have been synthesized. The X-ray structural analysis of{[Co(ClO₄)(H₂O)(L)][Co(H₂O)₂(L)]}(ClO₄)₃ shows two different metal sites in octahedral coordination. The EPR spectraof powdered samples of this compound are typical of distorted six-coordinated Co(II) ions in a high-spin (S = 3/2)configuration, with the ground state being S = 1/2 (g₁ = 5.20, g₂ = 3.20, g₃ = 1.95). The EPR spectrum of[Cu(ClO₄)(L)](ClO₄) was simulated assuming an axial g tensor (g₁ = g₂ = 2.043, g₃ = 2.145), while that of[Cu(ClO₄)(L1)](ClO₄) slightly differs from an axial symmetry (g₁ = 2.025, g₂ = 2.060, g₃ = 2.155). These resultsare compatible with a Cu(II) ion in square-pyramidal coordination with N₂S₂ as basal ligands. Single-crystal EPRexperiment performed on [Cu(ClO₄)(L1)](ClO₄) allowed determining the eigenvalues of the molecular g tensorassociated with the copper site, as well as the two possible orientations for the tensor. On the basis of symmetryarguments, an assignment in which the eigenvectors are nearly along the Cu(II)-ligand bonds is chosen.