Dimeric Complexes of a Tridentate Schiff Base Ligand – Crystal Structure of a Cu II Complex with Uncommon μ 2 ‐N sulfonamido Bridges and Ferromagnetic Behaviour

N ‐[2‐(Tosylamino)benzylidene]‐2‐[(tosylamino)methyl]aniline(H 2 L) has afforded M II 2 (L) 2 · x MeCN · y H 2 O complexes (M = Ni, Pd, Cu, Zn and Cd; x = 0 or 2; y = 0, 4, 6 or 8). Physicochemical characterisation data are indicative of the dinuclear nature of the complexes obtained, where the potential N,N,N‐donor L behaves as a dianionic and tridentate ligand. The crystal structure of Cu 2 (L) 2 · 2MeCN was solved, and it demonstrates that a double μ 2 ‐N sulfonamido bridge assembles the neutral Cu 2 (L) 2 dimers. This uncommon connection gives rise to a totally planar and nearly square‐shaped Cu 2 N 2 metallacycle. The planar geometries around the copper ions undergo a seesaw‐shaped distortion, which is probably related to secondary Cu ··· O interactions with neighbouring tosyl groups. This spatial arrangement seems related to the ferromagnetic behaviour shown by the complex.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)