Structure and Magnetism of a New Dodecanuclear Cu II Complex with Acetato and Imidazolato Bridges, Formed by Oxidation of the Chelating Ligand 1,1,7,7‐Tetrakis(imidazol‐2‐yl)‐2,6‐diazaheptane

A novel dodecanuclear copper( II ) complex [Cu 12 (tidhd) 4 (MeOH) 8 (CH 3 COO) 8 ](MeOH) 0.8 (Htidhd = 1,1,7,7‐tetrakis(imidazol‐2‐yl)‐2,6‐diaza‐1,6‐heptadiene) with imidazolato and acetato bridging ligands was synthesized by reaction of polyimidazole 1,1,7,7‐tetrakis(imidazol‐2‐yl)‐2,6‐diazaheptane (Htidahp) with copper acetate in a methanol solution. The complex crystallized in the triclinic space group P $\bar 1$ with a = 9.1204(1), b = 13.5139(2), c = 27.6925(5), α = 76.8006(6)°, β = 82.8066(7)°, γ = 76.4594(9)°, Z = 1. Structure analysis shows that the unit cell of the complex contains twelve copper( II ) ions in three different coordination environments. The complex is centrosymmetric and the two hexanuclear units are linked by two μ 3 ‐acetate anions [the Cu1−Cu1a distance is 3.5507(7) Å]. The magnetic superexchange interaction via the bridging imidazolate ligand appears to be the most important magnetic interaction in this complex. Magnetic susceptibility measurement vs. temperature in the range of 6−300 K were fitted to the parameters g = 2.05, J a = −32.0 cm −1 and J b  = −5.45 cm −1 . (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)