Agata Bartyzel

Synthesis, crystal structure and characterization of manganese(III) complex containing a tetradentate Schiff base

N,N′-bis((2-hydroxyphenyl)(phenyl)methylidene)propane-1,2-diaminato-N,N′,O,O′)-(nitrato-O)-manganese(III) methanol solvate ([Mn(C29H24N2O2)(NO3)CH3OH]) was synthesized and characterized by FTIR, UV–Vis, TG–FTIR, TG/DSC, molar conductivity, magnetic moment measurement and single crystal X-ray analysis. In the structure, the Mn(III) ion adopts a distorted octahedral geometry with two nitrogen and two oxygen atoms from the Schiff base ligand in the equatorial plane, and the nitrate ion and methanol molecule in the axial position. The effects of organic solvents of various polarities on the UV–Vis spectra of the ligand and complex were investigated. The manganese(III) complex is easily dissolved in organic polar aprotic solvents and has moderate solubility in organic polar protic solvents.

The formation of a neutral manganese(III) complex containing a tetradentate Schiff base and a ketone – synthesis and characterization

2-Benzoylphenolato-(2,2′-((2,2-dimethylpropane-1,3-diyl)bis((nitrilo)(phenylmethylidyne)))-diphenolato-manganese(III) methanol solvate, [Mn(C31H28N2O2)(C13H9O2)]·CH3OH (1), was synthesized and characterized by FTIR, UV–vis, TG-FTIR, TG/DSC, molar conductivity, magnetic moment measurement, and quantum chemical calculations. During the synthesis, partial hydrolysis of ligand is observed. The compound was obtained as amorphous, dark-brown powder. The effects of organic solvents of various polarities on the UV–vis spectra of ligands and complex were investigated. In addition, the IR and UV–vis spectra were also calculated and compared with the experimental data. A single crystal for analysis was obtained by dissolving the amorphous complex in methanol, and slow evaporation of solvent at 4 °C. Single-crystal X-ray analysis indicated that the methanol molecules are not incorporated into the crystal lattice after the recrystallization process ([Mn(C31H28N2O2)(C13H9O2)] (2)). In the structure Mn(III) is surrounded by two nitrogens and four oxygens of deprotonated Schiff base and α-hydroxy ketone ligands, and adopts a distorted octahedral geometry. Graphical abstract

Synthesis and characterization of triaquabis(1,1-cyclobutanedicarboxylato-O,O′,O″,O′″)dimanganese(II)

The manganese(II) complex, [Mn2(C6H6O4)2(H2O)3] was synthesized and characterized by X-ray crystallography, IR spectra and thermal analysis. The manganese salt crystallizes in the monoclinic system, space group C 2/c . Mn ions are coordinated to six oxygen atoms. The coordination polyhedron around the Mn ion can be described as a distorted octahedron. The manganese(II) complex has a chain structure. The repeating dimeric unit consists of Mn(II) atoms bridged by oxygens from two carboxylate ligands and one water molecule. The carboxylate ligands occur as tridentate-bridging and monodentate. The compound dehydrates at 403 K and then decomposes at 500 K first to Mn2O3 which transforms into Mn3O4 at 1183 K. The thermal decomposition is connected with release of water (405 K), carbon dioxide (470 K) and hydrocarbons (595 K). The IR spectra of the salt are discussed. # 2003 Elsevier Science Ltd. All rights reserved.

The crystal structure of a Terbium(III) complex with 1,1-Cyclobutanedicarboxylic acid

A complex of 1,1-cyclobutanedicarboxylic acid with terbium was obtained as a pentahydrate. The salt crystallizes in the monoclinic system, space group P21/n with a = 15.885(3), b = 8.489(2), c = 19.189(4) Å, β = 106.02(3)° and Z = 4. The structure was solved by direct methods and refined to R = 0.0537. The complex forms polymeric chains in which terbium(III) ions are linked by carboxylate bridges. Each terbium cation is surrounded by carboxylate oxygen atoms and two or three water oxygen atoms, giving coordination number 9. The structure is stabilized by a system of hydrogen bonds.

Synthesis, thermal study and some properties of N2O4—donor Schiff base and its Mn(III), Co(II), Ni(II), Cu(II) and Zn(II) complexes

The new hexadentate N2O4 Schiff base ligand from condensation of 2,4-hydroxybenzophenone and 1,3-propanediamine has been prepared in methanol and ethanol solutions. The Schiff base synthesized from EtOH contains half molecule of amine per one molecule of ligand in its structure. The complexes were synthesized from the direct reaction of this ligand and Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) acetates. The Schiff base and its complexes were characterized by elemental analysis, X-ray crystallographic techniques, spectroscopic (UV–Vis, IR) and thermal (TG, TG-FTIR) methods, molar conductance and magnetic measurements. The complexes, except for Ni(II) compound, similar to the Schiff base are amorphous solids. The Ni(II) complex crystallizes in the monoclinic space group P21/c. The N2O2 coordination geometry around nickel(II) is slightly tetrahedrally distorted square planar. Variable temperature magnetic studies of the paramagnetic complexes show the existence of weak antiferromagnetic [for complexes of manganese(III) and cobalt(II)] and weak ferromagnetic [for copper(II)] interactions. The complexes are stable at ambient temperature. After heating at first they lose solvent molecules (water or methanol), and after that organic part undergoes defragmentation and combustion. Based on the obtained data from the TG-FTIR analysis, the main gaseous products resulting from thermal degradation in nitrogen atmosphere are CO2, CO, NH3, acetic acid, methane, C6H6, C6H5CN and C6H5CH3.

Inorganic–organic hybrid materials based on PbBr2 and pyridine–hydrazone blocks – structural and theoretical study

Five lead(II) coordination compounds based on PbBr2 and a series of neutral hydrazone and hydrazine ligands (L1–L5) were prepared and structurally characterised, namely [Pb(μ2-Br)(Br)(L1)]2 (1), [Pb(μ2-Br)(Br)(μ2-L2)]n (2), [Pb(μ2-Br)(Br)(μ3-L3)]n (3), [Pb(μ2-Br)(Br)(μ2-L4)]n (4) and [Pb3(μ3-Br)2(μ2-Br)4(L5)2]n (5). In all compounds, there are bridging bromide ligands that interconnect Pb(II) centres and generate either [PbBr2]2 dimers (in 1, 2 and 3) or [PbBr2]n chain motifs (in 4) and [Pb3Br6]n ribbons (in 5). These correspond to three structural fragments present in the lead(II) bromide structure. Depending on the terminal (in 1 and 5) or μ2- and μ3-bridging (in 2, 3 and 4) coordination modes of organic building blocks, the [PbBr2]n fragments constitute discrete molecules (1) or extend to structurally distinct 1D (2 and 5) or 2D (3 and 4) metal–organic networks. Topological analysis and classification of these networks in 2–5 were performed, disclosing underlying chains or layers with the 2C1, 3,4L83, hcb topologies, and a trinodal 3,4,6-connected net of unprecedented topology, respectively. Theoretical calculations (DFT) were employed to analyze some relevant noncovalent interactions observed in the solid state. In particular the inter-ligand π–π stacking interactions in 1 and the influence of the metal coordination on their strength were analyzed. In 3, the role of intramolecular tetrel and π–hole unconventional interactions in the solid state architecture was demonstrated.

Adsorption of V(V), Mo(VI) and Cr(VI) Oxoanions by Chitosan–Silica Composite Synthesized by Mannich Reaction

Immobilization of chitosan on modified silica surface has been carried out by aminomethylation (Mannich reaction). The obtained chitosan–silica (CSS) composite was characterized by the Fourier transform infrared spectroscopy, specific surface area and pore diameter. The concentration of chitosan in the composite was determined by the thermogravimetric method. The effects of various parameters, such as pH, contact time, initial concentration of the metal on the adsorption of V(V), Mo(VI) and Cr(VI) oxoanions by the CSS composite were investigated in comparison with the initial components: chitosan, amino-containing silica and silica. The maximum adsorption capacities of composite with respect to V(V) and Mo(VI) oxoanions at pH 2.5 were 1.6 and 1.5 mmol/g, respectively, and 0.5 mmol/g towards Cr(VI) in the neutral medium.

Synthesis And Characterization Of Complexes Of Rare Earth Elements With 1,1-Cyclobutanedicarboxylic Acid

The complexes of yttrium and lanthanide with 1,1-cyclobutanedicarboxylic acid of the formula: Ln2(C6H6O4)3⋅nH2O, where n=4 for Y, Pr–Tm, n=5 for Yb,Lu, n=7 for La, Ce have been studied. The solid complexes have colours typical of Ln3+ ions. During heating in air they lose water molecules and then decompose to the oxides, directly (Y, Ce, Tm, Yb) or with intermediate formation. The thermal decomposition is connected with released water (313–353 K), carbon dioxide, hydrocarbons(538–598 K) and carbon oxide for Ho and Lu. When heated in nitrogen they dehydrate to form anhydrous salt and next decompose to the mixture of carbon and oxides of respective metals. IR spectra of the prepared complexes suggest that the carboxylate groups are bidentate chelating.

Crystal Structure, Thermal Analysis and Spectroscopic Study of Sodium 3,4-Diaminobenzoate

The structure and infrared spectrum of sodium 3,4-diaminobenzoate have been studied. The sodium salt crystallizes in the orthorhombic system, space group Pcab with a = 6.1940(10), b = 14.285(3), c = 21.348(4) Å, and Z = 8. The compound is polymeric in which Na ions are coordinated to six oxygen atoms, with Na-O distances ranging from 2.3380(14)-2.5856(18) Å. The compound dehydrates at 340 K and is decomposed at 485 K. IR spectra of the salt are discussed.

Synthesis, thermal behaviour and some properties of CuII complexes with N,O-donor Schiff bases

The complexes of N2O2-, N2O3- and N2O5-donors Schiff bases with CuII ions in the methanol solution have been synthesized. They were characterized by elemental analysis, X-ray crystallographic techniques, spectroscopic (UV–Vis, IR) and thermal (TG, TG-FTIR) methods. The catalytic activity of the prepared complexes for the hydrogen peroxide-assisted degradation of methylene blue (MB) as the model compound in water was also investigated. The complexes were obtained as crystalline solids. Depending on the Schiff bases and the molar ratio of CuII:ligand used in the synthesis, they can form monomeric or dimeric structures. The coordination environment around the metal centre in both solution and solid states is a slightly distorted square-planar. The values of magnetic moments determined at room temperature show the existence of antiferromagnetic interactions. The complexes are stable at ambient temperature. After heating, at first solvates lose solvent molecules; after that, an organic part undergoes gradual defragmentation and combustion. Degradation efficiency of MB in the presence of complexes was found to be 68.18–97.47%. A tentative mechanism involving HO· radical as an oxidant for degradation of MB was proposed.