A study on two unusual heterohexanuclear [CuII4LnIII2] (LnIII = LaIII and CeIII) complexes with a N2O2- and O6-donor bis(salamo)-based ligand

Abstract

Two unusual heterobimetallic [Cu II 4 Ln III 2 ] complexes were constructed from a N 2 O 2 - and O 6 -donor bis(salamo)-based ligand (H 4 L), and characterized structurally. The intermolecular interactions were quantitatively analyzed by Hirshfeld surfaces, as well as, fluorescence properties have also been studied. • Two structurally novel heterobimetallic hexanuclear [Cu II 4 Ln III 2 ] complexes were prepared using a designed N 2 O 2 - and O 6 -donor bis(salamo)-based ligand. • The different natures of three-compartmental H 4 L lead to the site‐selective introduction of two various metal II/III atoms. • Quantitative analyses of intermolecular interactions were evaluated by Hirshfeld surfaces analyses. • The fluorescence properties were further discussed. Two unusual heterobimetallic [Cu II 4 Ln III 2 ] complexes, [{Cu 4 (L) 2 La 2 ( ƞ 2 -NO 3 ) 6 (EtOH)}]·2Me 2 CO ( 1 ) and [{Cu 4 (L) 2 Ce 2 ( ƞ 2 -NO 3 ) 6 (EtOH)} 2 ]·4Me 2 CO·MeOH ( 2 ) were constructed from a N 2 O 2 - and O 6 -donor bis(salamo)-based ligand (H 4 L). The structures were characterized by physical chemistry and spectroscopy methods. The two complexes 1 and 2 have similar structures, two heterotrinuclear parts with the same structure are linked by the coordination between one Cu II atom and oxime-type oxygen atoms to obtain the heterohexanuclear complexes 1 and 2 . Four penta-coordinate Cu II atoms are located at the N 2 O 2 cavities of the ligand (L) 4- units, two La III /Ce III atoms are surrounded by the open-chain 18-crown-6 (O 6 ) coordination environment. At the same time, eight bridged phenol oxygen atoms connect the six Cu II /Ln III atoms. Infinite three-dimensional supra-molecular structures are formed in complexes 1 and 2 through H-bonds. The intermolecular interactions were quantitatively analyzed by Hirshfeld surfaces, as well as, fluorescence properties have also been studied.