Solution and solid state studies on Cu(II) complexes of pyridine-2-hydroxamic acid (HPicHA) and pyridine-2,6-dihydroxarnic acid (H(2)PyDHA) were came out. The use of methanol/water solvent allowed us to investigate the Cu(II)-HPicHA equilibria under homogeneous conditions between pH 1 and 11. In agreement with ESI-MS indication, the potentiometric data fitted very well with the model usually reported for copper(II) complexes of alpha-arninohydroxarnate complexes ([CuL](+), [Cu-5(LH-1)(4)](2+), [CuL2], [CuL2H-1](-)), however with much higher stability of the 12-MC-4 species. A series of copper(H) complexes has been isolated in the solid state and characterized by a variety of spectroscopic methods, X-ray structure analysis, and Magnetic susceptibility measurements. The ligands show the tendency to form bi- and trinuclear species with copper(II) ions due to the {(N,N'); (O,O')} bis-(bidentate) chelating-and-bridging mode involving (O,O')-hydroxarnate chelate formation combined with (N,N') chelating with participation of the pyridine and hydroxamic nitrogen atoms, so that the hydroxamate groups play a mu(2)-(N,O)-bridging role. Molecular and crystal structures of three synthesized complexes [Cu-3(PicHA-H)(2)(dipy)(2)](ClO4)(2 center dot)4/3DMSO center dot 2/3H(2)O (1), [Cu-2(PyDHA)-(dipy)(2)(ClO4)(2)]center dot DMF center dot H2O (4), and [Cu-3(PyDHA-2H) (tmeda)(3)](ClO4)(2) (5) (dipy, 2,2'-dipyridyl; tmeda, N,N,N',N'-tetramethyl-1,2-diaminoethane) have been determined by single crystal X-ray analysis. In 1, two trans-situated doubly deprotonated hydroxamic ligands play a {(O,O')(N,N')-(bis)bidentate-bridging function forming bridges between the medial, Cu(2) (CuN4), and the terminal, Cu(1) and Cu(3) (CuN2O2), copper(II) ions; the chelating dipy ligands are coordinated to the latter. In 4, the ligand is coordinated in a classical (O,O')-hydroxamate chelating mode with the help of two separate hydroxamic groups while the central tridentate donor compartment remains vacant. In 5, the hydroxamate ligand is coordinated by the {(O,O');(N,N',N '');(O '',O '''}-tridentate-(bis)bidentate mode, bridging three copper(II) ions, while the chelating tmeda ligands are coordinated to all three copper(II) ions. Magnetic susceptibility measurements (1.7-300 K) of powdered samples of the trinuclear complexes 1 and 5 revealed strong antiferromagnetic coupling between the copper(II) ions mediated by the hydroxamate bridges.