Synthesis and Characterization of Three Diverse Coordination Frameworks under Co-ligand Intervention

The chelating organic ligands of 2,2'-bipyridine (2,2'-bipy), di(pyrid-2-yl)amine (dpa) and 2,6-di(pyrid-2-ylamino)pyridine (dpap) were respectively applied to react with H(2)fum (fumaric acid) and copper salts, affording three different complexes [Cu-2(fum)(2,2'-bipy)(4)]center dot 2ClO(4) (1), [Cu-2(mu-OH)(2)(fum)(dpa)2]center dot 2H(2)O (2) and [Cu(SO4)(H2O)(dpap)]center dot H2O (3). These complexes were determined by single-crystal X-ray diffraction. Each penta-coordinated Cu(II) ion exhibits a distorted trigonal bipyramidal geometry in 1. The fum ligand links copper ions to form a dinuclear copper unit. While in 2, the fum ligands connect [Cu-2(mu-OH)(2)(dpa)(2)] unit to construct a 1D zigzag chain. Unexpectedly, when dpap instead of dpa was used under the same conditions, only one mononuclear complex 3 was formed. Crystal packings show that 1-3 form 3D supramolecular architectures through non-covalent interactions (multiple hydrogen bonds and C-H center dot center dot center dot pi/pi-pi interactions). In addition, the study of the magnetic property reveals dominating ferromagnetic interactions between Cu(II) atoms in 1.