Synthesis, crystal structure, fluorescence properties and theoretical calculations of heterobimetallic 3d–4f complex with a flexible bis(salamo)‐type ligand

Abstract

A new heterobimetallic 3d-4f [Cu(II)2Pr(III)] complex [Cu2Pr(L)(ƞ2-NO3)3(EtOH)2]·2EtOH with a symmetric flexible bis(salamo)-type ligand, (1E,1′E)-2,3-dihydroxynaphthalene-1,4-dicarbaldehyde O,O-di(3-((((E)-3-ethoxy-2-hydroxybenzylidene)amino)oxy)propyl)dioxime (H4L), has been synthesized and characterized structurally. Single crystal X-ray diffraction analysis showed that the ligand was fasten by different metal ions to form a hetero-trinuclear complex with C-shaped structure, where two N2O2-donors of the completely deprotonated ligand (L)4− unit and two oxygen atoms from two ethanol molecules coordinate with Cu(II) atoms (Cu1, Cu2), respectively, to form two five-coordinated square pyramid geometries. Meanwhile, where the O6 cavity coordination sphere of the ligand (L)4− unit and six oxygen atoms from three nitrate groups coordinate with the Pr(III) atom together to form a twelve-coordinated icosahedron. Due to the Cu(II) atom in the O6 cavity was replaced by the Pr(III) atom, it shows that the hetero-trinuclear complex after self-assembly is more stable than the homo-trinuclear complex. At the same time, through UV–Vis titration spectrometric analysis, we can observed that the hetero-trinuclear [Cu(II)2Pr(III)] complex is obtained by 1 equiv. Pr(NO3)3·5H2O and 2 equiv. Cu(NO3)2·3H2O and 1 equiv. H4L. Significantly, fluorescence properties and Hirshfeld surfaces analyses of the [Cu(II)2Pr(III)] complex was also studied.