Supramolecular Assemblies of Trinuclear Copper(II)-Pyrazolato Units: A Structural, Magnetic and EPR Study

Two anionic complexes, {[Cu-3(mu(3)-OH)(mu-4-Ph-pz)(3)Cl-3](2)[Cu(4-Ph-pzH)(4)](mu-Cl)(2)}(2-) (1) and [Cu-3(mu(3)-OH)(mu-pz)(3)(mu(1,1)-N-3)(2)(N-3)](-) (2), crystallize as one-dimensional polymers, held together by weak Cu-(mu-Cl) and Cu-(mu-N-3) interactions, respectively. Variable temperature magnetic susceptibility analyses determined the dominant antiferromagnetic intra-Cu-3 exchange parameters in the solid state for both complexes, whereas the weak ferromagnetic inter-Cu-3 interactions manifested also in the solid state EPR spectra, are absent in the corresponding frozen solution spectra. DFT calculations were employed to support the results of the magnetic susceptibility analyses.