Cyanide-bridged trinuclear MnIII–FeIII assembly: Crystal structure, magnetic and photoluminescence behavior

Eu@PMMA and Sm@PMMA nanofibers prepared by electrospinning: structure, morphology, luminescence and magnetic properties

Eu³⁺ and Sm³⁺ coordination polymers and a series of Eu@PMMA and Sm@PMMA nanofibers were prepared. Color tunability was achieved with the luminescence changing from reddish orange in the bulk state to near-white light in the nanofiber stage.

The syntheses, crystal structures, electrochemical and magnetic properties of tri-nuclear cyanide-bridged complexes [cis-MII(bpy)2(CN)2]2MnIII(salcy) (PF6) (M = Fe, Ru, Os)

Three cyanide-bridged heteronuclear complexes, [cis-M(bpy)₂(CN)₂]₂Mn(salcy) (PF₆) (M = Fe, 1; M = Ru, 2; M = Os, 3; bis(salicylideneiminato) dianion) were synthesized and fully characterized. Complexes 1 and 2 show low temperature antiferromagnetic order.

Construction and photoluminescence properties of a three-dimensional ZnII coordination network based on naphthalene-1,4-dicarboxylic acid and 1,6-bis(pyridin-3-yl)-1,3,5-hexatriene

In recent years, coordination polymers constructed from multidentate carboxylate and pyridyl ligands have attracted much attention because these ligands can adopt a rich variety of coordination modes and thus lead to the formation of crystalline products with intriguing structures and interesting properties. A new coordination polymer, namely poly[[μ₂-1,6-bis(pyridin-3-yl)-1,3,5-hexatriene-κ²N:N'](μ₃-naphthalene-1,4-dicarboxylato-κ⁴O¹,O^1':O⁴:O^4')zinc(II)], [Zn(C₁₂H₆O₄)(C₁₆H₁₄N₂)]_n, has been prepared by the self-assembly of Zn(NO₃)₂·6H₂O, naphthalene-1,4-dicarboxylic acid (1,4-H₂ndc) and 1,6-bis(pyridin-3-yl)-1,3,5-hexatriene (3,3'-bphte) under hydrothermal conditions. The title compound has been structurally characterized by IR spectroscopy, elemental analysis, powder X-ray diffraction and single-crystal X-ray diffraction analysis. Each Zn^II ion is six-coordinated by four O atoms from three 1,4-ndc^2- ligands and by two N atoms from two 3,3'-bphte ligands, forming a distorted octahedral ZnO₄N₂ coordination geometry. Pairs of Zn^II ions are linked by 1,4-ndc^2- ligands, leading to the formation of a two-dimensional square lattice (sql) layer extending in the ab plane. In the crystal, adjacent layers are further connected by 3,3'-bphte bridges, generating a three-dimensional architecture. From a topological viewpoint, if each dinuclear zinc unit is considered as a 6-connected node and the 1,4-ndc^2- and 3,3'-bphte ligands are regarded as linkers, the structure can be simplified as a unique three-dimensional 6-connected framework with the point symbol 4⁴6¹⁰8. The thermal stability and solid-state photoluminescence properties have also been investigated.

Structural and spectroscopic characterization of a new luminescent NiII complex: bis{2,4-dichloro-6-[(2-hydroxypropyl)iminomethyl]phenolato-κ3O,N,O'}nickel(II)

The design and preparation of transition-metal complexes with Schiff base ligands are of interest due to their potential applications in the fields of molecular magnetism, nonlinear optics, dye-sensitized solar cells (DSSCs), sensing and photoluminescence. Luminescent metal complexes have been suggested as potential phosphors in electroluminescent devices. A new luminescent nickel(II) complex, [Ni(C₁₀H₁₀Cl₂NO₂)₂], has been synthesized and characterized by single-crystal X-ray diffraction and elemental analysis, UV-Vis, FT-IR, ¹H NMR, ¹³C NMR and photoluminescence spectroscopies, and LC-MS/MS. Molecules of the complex in the crystals lie on special positions, on crystallographic binary rotation axes. The Ni^II atoms are six-coordinated by two phenolate O, two imine N and two hydroxy O atoms from two tridentate Schiff base 2,4-dichloro-6-[(2-hydroxypropyl)iminomethyl]phenolate ligands, forming an elongated octahedral geometry. Furthermore, the complex exhibits a strong green luminescence emission in the solid state at room temperature, as can be seen from the (CIE) chromaticity diagram, and hence the complex may be a promising green OLED (organic light-emitting diode) in the development of electroluminescent materials for flat-panel-display applications.

Crystal structure and photoluminescence properties of a new monomeric copper(II) complex: bis(3-{[(3-hydroxypropyl)imino]methyl}-4-nitrophenolato-κ3O,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^II complex, [Cu(C₁₀H₁₁N₂O₄)₂], has been synthesized by the reaction of 3-{[(3-hydroxypropyl)imino]methyl}-4-nitrophenol (H₂L) 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^II 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 H₂L have been investigated at room temperature in the visible region. When the complex and H₂L are excited under UV light at 349 nm, the complex displays a strong green emission at 520 nm and H₂L displays a blue emission at 480 nm.

A new stepped tetranuclear copper(II) complex: synthesis, crystal structure and photoluminescence properties

Binuclear and tetranuclear copper(II) complexes are of interest because of their structural, magnetic and photoluminescence properties. Of the several important configurations of tetranuclear copper(II) complexes, there are limited reports on the crystal structures and solid-state photoluminescence properties of `stepped' tetranuclear copper(II) complexes. A new Cu^II complex, namely bis{μ₃-3-[(4-methoxy-2-oxidobenzylidene)amino]propanolato}bis{μ₂-3-[(4-methoxy-2-oxidobenzylidene)amino]propanolato}tetracopper(II), [Cu₄(C₁₁H₁₃NO₃)₄], has been synthesized and characterized using elemental analysis, FT-IR, solid-state UV-Vis spectroscopy and single-crystal X-ray diffraction. The crystal structure determination shows that the complex is a stepped tetranuclear structure consisting of two dinuclear [Cu₂(L)₂] units {L is 3-[(4-methoxy-2-oxidobenzylidene)amino]propanolate}. The two terminal Cu^II atoms are four-coordinated in square-planar environments, while the two central Cu^II atoms are five-coordinated in square-pyramidal environments. The solid-state photoluminescence properties of both the complex and 3-[(2-hydroxy-4-methoxybenzylidene)amino]propanol (H₂L) have been investigated at room temperature in the visible region. When the complex and H₂L are excited under UV light at 349 nm, the complex displays a strong blue emission at 469 nm and H₂L displays a green emission at 515 nm.

Designing a heterotrinuclear Cu(II)-Ni(II)-Cu(II) complex from a mononuclear Cu(II) Schiff base precursor with dicyanamide as a coligand: synthesis, crystal structure, thermal and photoluminescence properties

Schiff bases are considered `versatile ligands' in coordination chemistry. The design of polynuclear complexes has become of interest due to their facile preparations and varied synthetic, structural and magnetic properties. The reaction of the `ligand complex' [CuL] {H2L is 2,2'-[propane-1,3-diylbis(nitrilomethanylylidene)]diphenol} with Ni(OAc)2·4H2O (OAc is acetate) in the presence of dicyanamide (dca) leads to the formation of bis(dicyanamido-1κN(1))bis(dimethyl sulfoxide)-2κO,3κO-bis{μ-2,2'-[propane-1,3-diylbis(nitrilomethanylylidene)]diphenolato}-1:2κ(6)O,O':O,N,N',O';1:3κ(6)O,O':O,N,N',O'-dicopper(II)nickel(II), [Cu2Ni(C17H16N2O2)2(C2N3)2(C2H6OS)2]. The complex shows strong absorption bands in the frequency region 2155-2269 cm(-1), which clearly proves the presence of terminal bonding dca groups. A single-crystal X-ray study revealed that two [CuL] units coordinate to an Ni(II) atom through the phenolate O atoms, with double phenolate bridges between Cu(II) and Ni(II) atoms. Two terminal dca groups complete the distorted octahedral geometry around the central Ni(II) atom. According to differential thermal analysis-thermogravimetric analysis (DTA-TGA), the title complex is stable up to 423 K and thermal decomposition starts with the release of two coordinated dimethyl sulfoxide molecules. Free H2L exhibits photoluminescence properties originating from intraligand (π-π*) transitions and fluorescence quenching is observed on complexation of H2L with Cu(II).

Crystal structure and photoluminescence properties of a new CdIIcoordination polymercatena-poly[bis[4-bromo-2-({[2-(pyrrolidin-1-yl)ethyl]imino}methyl)phenolato-κ3N,N′,O]di-μ3-chlorido-di-μ2-chlorido-bis(methanol-κO)tricadmium(II)]

Schiff base–metal complexes have been used widely as catalysts for many organic reactions, such as ring-opening polymerization and oxidation. In view of the importance of CdIIcoordination polymers and in an effort to enlarge the library of such complexes, the title novel polymeric CdIItridentate Schiff base complex, [Cd3(C13H16BrN2O)2Cl4(CH4O)2]n, has been synthesized and characterized by elemental analyses, UV and IR spectroscopies, and single-crystal X-ray diffraction. The complex crystallizes in the triclinicP\overline{1} space group with two symmetry-independent CdIIatoms, one of which lies on an inversion centre, and analysis of the crystal structure shows that both CdIIatoms are six-coordinated; the environment around one CdIIatom can be described as distorted octahedral, while that around the second CdIIatom is octahedral. The CdIIatoms are linked by chloride ligands to form a one-dimensional coordination polymer. The nonbonding intermolecular Cd...Cd distances are 3.7009 (4) and 4.3563 (5) Å. Furthermore, the photoluminescence properties of the complex have been investigated and it displays a strong red emission in the solid state at room temperature.