Crystal structure and photoluminescence properties of a new monomeric copper(II) complex: bis(3-{[(3-hydroxypropyl)imino]methyl}-4-nitrophenolato-κO,N,O')copper(II).

Copper(II)-Schiff base complexes have attracted extensive interest due to their structural, electronic, magnetic and luminescence properties. The title novel monomeric Cu complex, [Cu(CHNO)], has been synthesized by the reaction of 3-{[(3-hydroxypropyl)imino]methyl}-4-nitrophenol (HL) and copper(II) acetate monohydrate in methanol, and was characterized by elemental analysis, UV and IR spectroscopies, single-crystal X-ray diffraction analysis and a photoluminescence study. The Cu atom is located on a centre of inversion and is coordinated by two imine N atoms, two phenoxy O atoms in a mutual trans disposition and two hydroxy O atoms in axial positions, forming an elongated octahedral geometry. In the crystal, intermolecular O-H...O hydrogen bonds link the molecules to form a one-dimensional chain structure and π-π contacts also connect the molecules to form a three-dimensional structure. The solid-state photoluminescence properties of the complex and free HL have been investigated at room temperature in the visible region. When the complex and HL are excited under UV light at 349 nm, the complex displays a strong green emission at 520 nm and HL displays a blue emission at 480 nm.