Synthesis, structure and properties of a tetranuclear europium(III) complex based on 9,9-dimethylfluorene-2,7-diphosphonic acid

• An europium(III) phosphonate (EuMFDP) has been synthesized.
• The ligand is 9,9-dimethylfluorene-2,7-diphosphonic acid (H4MFDP).
• EuMFDP features a strip-like tetranuclear structure.
• EuMFDP exhibits very weak red emission.
• IR spectrum and TGA have also been discussed.

One tetranuclear europium(III) phosphonate complex [Eu2(H4MFDP)(H3MFDP)4(H2MFDP)(H2O)4]·13.5H2O (EuMFDP), has been prepared by reactions of the new ligand 9,9-dimethylfluorene-2,7-diphosphonic acid (H4MFDP) with europium(III) nitrates. The crystal structure of complex EuMFDP has been determined using single-crystal X-ray diffraction. It features a strip-like tetranuclear structure, in which four ligands and four Eu(III) ions constitute the core. Interestingly, the four ligands in the core possess paddle-like arrangement. Although the free ligand H4MFDP exhibits the emission centered at 333 nm and 438 nm upon excitation at 310 nm, complex EuMFDP shows only very weak characteristic emission of Eu(III) ions, probably due to the strong quenching effect of OH vibration. The thermal property of EuMFDP has also been studied.

One tetranuclear europium(III) complex (EuMFDP) constructed from 9,9-dimethylfluorene-2,7-diphosphonic acid (H4MFDP) has been synthesized. EuMFDP features a strip-like tetranuclear structure with the core composed of four paddle-like arranged ligands and four Eu(III) ions. EuMFDP shows only very weak characteristic emission of Eu(III) ions, probably due to the strong quenching effect of OH vibration.Figure optionsDownload as PowerPoint slide