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 (NO 3 ) 2 ( μ ‐NO 3 )(H 2 O)]·EtOH ( 1 ), hetero‐tetranuclear 3d–4f complex [Cu(L)Ce (NO 3 ) 2 ( μ ‐NO 3 )(OAc) 2 ] 2 ·MeOH ( 2 ) and hetero‐multinuclear 3d–4f complexes [{Cu(L)Ln (NO 3 ) 3 } 2 ][Cu(L)Ln (NO 3 ) 3 ] 2 (Ln = Pr ( 3 ) and Nd = ( 4 )) have been self‐assembled from the reaction of Cu (OAc) 2 ·H 2 O, Ln (NO 3 ) 3 ·6H 2 O (Ln = La, Ce, Pr and Nd) with an unsymmetric salamo‐like bisoxime ligand H 2 L (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.