Crystal Structure and Photoluminescence of a Tetranuclear Cadmium Complex

A novel tetranuclear cadmium complex ([{Cd(C₁₅H₈O₇S)(H₂O)(DMSO)}₃{Cd(C₁₅H₈O₇S)(H₂O)₂}]·3DMSO·H₂O) was obtained by the self‐assembly of Cd(II) with 5,7‐dihydroxyflavone‐6‐sulfonate. The complex was characterized by ¹H NMR, IR, elemental analysis and X‐ray single‐crystal diffraction studies. It crystallizes in triclinic, space group $ P {bar 1} $ . In the complex, the chelate atoms of Cd(II) are all from oxygen. Four Cd(II) are connected via the carbonyl and 5‐hydroxyanion of four ligands and form an approximate square. Four ligands locate at two sides of the square, and two of them at the same side are almost parallel and exist aromatic π‐π stacking. Ligands on the opposite side of the square are nearly perpendicular. The result of the luminescent studies indicated that the solid of the complex shwed photoluminescent properties because of a combination of coordination, hydrogen bonding and π‐π stacking interaction in the molecule structure. The complex emits green fluorescence (λ_em=496 nm) when it is excited at the wavelength of 440 nm.