A new one-dimensional coordination polymer and a new supramolecular dimer made of trinuclear copper(II) complexes: crystal structure and magnetic properties

Two oxamato-bridged copper(II) complexes of formula [Cu-3(pbaOH)(tmen)(2)(H 2O)(ClO4)](n)[ClO4](n). nH(2)O 1 and [Cu-3(opba)(tmen)(2)(H2O)(3)][Cu-3(opb a)(tmen)(2)(H2O)(2)][ClO4](4). 3H(2)O 2 have been synthesized and character ized by IR, ESR, electronic spectra and X-ray crystallographic analyses, wh ere pbaOH(4-)=2-hydroxyl-N,N'-trimethylenebis(oxamate), opba(4-)=N,N'-o-phe nylenebis(oxamate), tmen=N,N,N',N'-tetramethylethylenediamine. Both complex es consist of cationic trinuclear entities, in which copper atoms reside in square-planar (4) or square-pyramidal (4+1) environments. In complex 1 the hydroxyl group of one trinuclear entity coordinates to a terminal copper a tom of another, thus forming an unusual one-dimensional chain. In 2 two nei ghboring trinuclear cations interact to form an interesting supramolecular (or "supracationic") dimer. The magnetic properties of the two complexes ha ve been investigated, indicating that two copper(II) ions bridged by the ox amato bridge interact antiferromagnetically with J=-334.4 cm(-1) for 1 and -356.6 cm(-1) for 2 (based on (H) over cap=-J (S) over cap (1).(S) over cap (2)).