Dimetallic complexes derived from a novel dinucleating chelating symmetric triazole ligand; crystal structure, magnetic properties and ESR study of bis[μ-3,5-diacetylamino-1,2,4-triazolato-O ′,N 1,N 2,O ″]bis[(nitrato)(aqua)copper(II)] ‡

Reaction of 3,5-diacetylamino-1,2,4-triazole (Hdaat) with copper(II), nickel(II) and cobalt(II) salts yields dinuclear co-ordination compounds, which were spectroscopically characterized. The crystal and molecular structure of one of the compounds, bis[µ-3,5-diacetylamino-1,2,4-triazolato-O′,N 1,N 2,O″]bis[(nitrato)(aqua)copper(II)] 1, was determined by single-crystal X-ray diffraction. Complex 1 consists of dinuclear units with an inversion center at the midpoint of the Cu–Cu vector. The most remarkable feature of this structure is that the daat ligand forms a six-membered chelate ring [Cu–N3–C3–N1–C2–O1; Cua–N4–C4–N5–C5–O2], in contrast with the five-membered chelate rings always found in…