Tetranuclear Eu(III)-Co(II) complex of an N4O4 macrocycle

•A monomeric Eu(III) complex with a protonated form of macrocyclic Schiff-base is used as precursor of Eu(III), Eu(III)-Co(II) and Co(II) complexes of deprotonated macrocycle.•Photophysical properties of the Eu(III) complex are presented.•The crystal structure of the mixed Co(II)-Eu(III) complex shows a unique dimer of macrocyclic heterometalic units.

The reaction of an Eu(III) complex of the protonated form of the macrocyclic Schiff base derived from 1,3-diamino-2-hydroxypropane and 2,6-diformylphenol, [Eu(H4L)Cl3], with three equivalents of base results in a mononuclear complex of the triply deprotonated form of the ligand, [Eu(HL)]. The photophysical properties of the [Eu(HL)] complex are discussed on the basis of emission and excitation spectra, as well as of the emission decay times. The [Eu(HL)] complex in a reaction with cobalt(II) chloride gives a heterometallic Eu(III)-Co(II) macrocyclic complex, [EuCo(HL)(CH3OH)2Cl]2Cl2·4CH3OH. In the presence of base and an excess of cobalt(II) chloride the starting [Eu(H4L)Cl3] complex is converted to a dinuclear Co(II) complex, [Co2(H2L)Cl2(CH3OH)2]·1.5CH3OH.

Graphical abstractReactivity of an Eu(III) complex of the deprotonated form of a macrocyclic Schiff base is reported leading to Eu(III), Eu(III)-Co(II) and Co(II) complexes.Figure optionsDownload full-size imageDownload as PowerPoint slide