Cyclic trinuclear and chain of cyclic trinuclear copper(II) complexes containing a pyramidal Cu(3)O(H) core. Crystal structures and magnetic properties of [Cu(3)(mu(3)-OH)(aaat)(3)(H(2)O)(3)](NO(3))(2).H(2)O [aaat = 3-acetylamino-5-amino-1,2,4-triazolate] and ([Cu(3)(mu(3)-OH)(aat)(3)(mu(3)-SO(4))].6H(2)O)(n) [aat = 3-acetylamino-1,2,4-triazolate]: new cases of spin-frustrated systems.

New copper(II) complexes of the cyclic trinuclear type with 1,2,4-triazole ligands, [Cu(3)(mu(3)-OH)(aaat)(3)(H(2)O)(3)](NO(3))(2).H(2)O [Haaat = 3-acetylamino-5-amino-1,2,4-triazole] (1) and ([Cu(3)(mu(3)-OH)(aat)(3)(mu(3)-SO(4))].6H(2)O)(n) [Haat = 3-acetylamino-1,2,4-triazole] (2), have been prepared and characterized by X-ray crystallography and magnetic measurements.