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

Abstract

Newly designed hetero‐dinuclear 3d–4f complex [Cu(L)La (NO3)2(μ‐NO3)(H2O)]·EtOH (1), hetero‐tetranuclear 3d–4f complex [Cu(L)Ce (NO3)2(μ‐NO3)(OAc)2]2·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·H2O, Ln (NO3)3·6H2O (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 complexes 1–4 were 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 complexes 1–4 are discussed in detail. Moreover, the antioxidant activities of the complexes 1–4 were determined by superoxide radical‐scavenging method in vitro, which indicates that the complexes 1–4 all show potential antioxidant properties.