Insights into crystal structures, supramolecular architectures and antioxidant activities of self-assembled fluorescent hetero-multinuclear [Cu (II)-Ln (III)] (Ln = La, Ce, Pr and Nd) salamo-like complexes

Newly designed hetero-dinuclear 3d-4f complex [Cu(L)La (NO3)(2)(mu-NO3)(H2O)]center dot EtOH (1), hetero-tetranuclear 3d-4f complex [Cu(L)Ce (NO3)(2)(mu-NO3)(OAc)(2)](2)center dot MeOH (2) and hetero-multinuclear 3d-4f complexes [{Cu(L)Ln (NO3)(3)}(2)][Cu(L)Ln (NO3)(3)](2)(Ln = Pr (3) and Nd = (4)) have been self-assembled from the reaction of Cu (OAc)(2)center dot H2O, Ln (NO3)(3)center dot 6H(2)O (Ln = La, Ce, Pr and Nd) with an unsymmetric salamo-like bisoxime ligand H2L (6-Methoxy-6 '-ethoxy-2,2 '-[ethylenedioxybis (nitrilomethylidyne)]diphenol) based on a Schiff base condensation of 2-[O-(1-ethoxyamide)]oxime-6-methoxyphenol and 3-ethoxysalicylaldehyde. The structures of complexes1-4were characterized by elemental analyses, PXRD analyses, IR, UV-Vis spectra, and single-crystal X-ray analyses. In addition, the supramolecular interactions and fluorescence properties of complexes1-4are discussed in detail. Moreover, the antioxidant activities of the complexes1-4were determined by superoxide radical-scavenging method in vitro, which indicates that the complexes1-4all show potential antioxidant properties.