Synthesis, characterization, and magnetic properties of new homotrinuclear bis(oxamato) copper(II) complexes with an asymmetric central N,N '-bridge

The new mononuclear bis(oxamato) complex [n-Bu4N](2)[Cu(obbo)] (1) (obbo=o-benzyl-bis(oxamato)) has been synthesized as a precursor for trinuclear oxamato-bridged transition metal complexes. Starting from 1 the homotrinuclear complexes [Cu-3(obbo)(pmdta)(2)(NO3)](NO3)center dot CH1Cl2 center dot H2O (2) and [Cu-3(obbo)(tmeda)(2)(NO3)(2)(dmf)] (3) have been prepared, where pmdta = N,N,N',N '',N ''-pentamethyldiethylenetriamine, tmeda = N,N,N',N'-tetramethylethylenediamine and dmf = dimethylformamide. The crystal structures of 1-3 were solved. The magnetic properties of 2 and 3 were studied by susceptibility measurements versus temperature. For the intramolecular J parameter values of -111 cm(-1) (2) and -363 cm(-1) (3) were obtained.