The systematic study of the reaction system copper(II) perchlorate/di-2-pyridyl ketone, (py) 2 CO, provided access to the new trinuclear compound [Cu 3 {(py) 2 C(OMe)(O)} 3 (H 2 O)](ClO 4 ) 3 ·MeOH·0.6H 2 O (1·MeOH·0.6H 2 O), and the 1D coordination polymer [Cu 2 {(py) 2 C(OEt)(O)}(HCO 2 ) 2 (ClO 4 )(MeCN)] n (2) bearing the anionic hemiketal forms of (py) 2 CO. Both compounds were prepared from reactions of Cu(ClO 4 ) 2 ·6H 2 O with the ligand, in the presence of NEt 3 in MeOH (1) or MeCN/TEOF (2), where TEOF is triethylorthoformate. Compound 1 possesses a triangular metal topology representing an example of a non-oxido/hydroxido/methoxido-centered Cu 3 species. Compound 2 is based on dinuclear units linked through HCO 2 − groups forming an 1D chain. EPR spectra and variable temperature dc magnetic susceptibility studies on powdered polycrystalline samples of 1 revealed the presence of strong antiferromagnetic interactions between the metal centers leading to an S=1/2 ground state. The magnetic susceptibility data were fit using a model including antisymmetric exchange interactions and the antisymmetric exchange vector parameter G Z value has been determined.