Applied Chemistry

Two tetradentate Schiff base ligands, N,N´-bis(2-hydroxy-5-methoxyacetophenone) ethylenediimine (MaenH₂) and N,N´-bis(2-hydroxy-4-methoxybenzophenone) ethylenediimine(MbenH₂) were formed by 1:2 molar condensation of ethylenediamine with 2-hydroxy-5-methoxyacetophenone and 2-hydroxy-4-methoxybenzophenone respectively. These Schiff base ligands formed complexes (1:1 molar ratio) with Copper, Nickel, Cobalt and Oxovanadium ions. The complexes were characterized by Infrared, Electronic Spectra and elemental analysis. The spectra data of the ligands and their complexes were discussed based on the structural changes which occur due to complexation. The results suggest that the metal is bonded to the ligand through the phenolic oxygen and the imino nitrogen.

ZnO nanorods were successfully fabricated by using the chemical precipitated method. We report the synthesis and characterization of several sizes of ZnO nanocrystals, both in the free standing and the capped particle forms. The sizes of these nanocrystals could be controlled by capping them with polyvinylpyrollidone and were estimated by X-ray diffraction and transmission electron microscopy. The chemical compositions of the products were characterized by FT-IR spectroscopy. UV -Vis absorption spectroscopy measurements reveal that the capping of ZnO leads to blue shift due to quantum confinement effect.PL emission spectrum of PVP encapsulated ZnO shows red shift due to defect oriented emission. The morphology of the particles was evaluated by scanning electron microscopy (SEM) and Transmission electron microscopy (TEM). Both the thermo gravimetric analysis (TGA) and differential thermal analysis (DTA) curves of the ZnO show that no further weight loss and thermal effect were observed at a temperature of above 510?C.

The crystal structure of the new inorganic-organic hybrid compound [4-OCH3C6H4CH2NH3]2[CdCl4] has been determined by single crystal X-ray diffraction The compound crystallizes in the triclinic space group P with lattice parameters a = 19.007(2), b = 7.3410(8), c = 7.4451(8) Å, , ? =97.222(1)°, V = 1030.59(19) Å3, and Z = 2. The framework of the title compound is built upon layers parallel to (100) made up from corner-sharing [CdCl6] octahedra. 4-methoxybenzylammonium cations are situated between the layers and connect them via an N-H…Cl hydrogen-bonding network. The Cd atom is located on an inversion centre and the coordination environment is described as distorted octahedra. Solid state 13C CP-MAS NMR spectroscopy is in agreement with the X – ray structure. DFT calculations allow the attribution of the carbon peaks to the independent crystallographic sites. Thermal analysis and Infrared spectroscopy were also used to characterize the complex.

A simple and efficient method has been developed for the synthesis of macrocyclic binuclear Schiff base ligand and their transition metal complexes of the type [M₂(L)X]  where M= Ni(II), Cu(II),   X=CH₃COO^? and [M₂(L)].X where M=Ni(II), Cu(II) and VO(II), X=4ClO₄^?, 2SO₄^2?. If the ligand have been synthesized by the condensation of 3,3’-diaminobenzidine with Phthaldehyde and O-phenylenediamine in the ratio 1:4:2. The prepared macrocyclic ligand and their metal complexes were structurally confirmed by analytical and spectral data and the bonding sites are the azomethine nitrogen atoms. The metal complexes exhibit different geometrical arrangements such as square planar and square pyramidal. The ligand and the complexes were evaluated for their antimicrobial activities. The results showed that this skeletal framework exhibit marked potency as antimicrobial agents.

Dihydro-3,4-dihydroxy-5-(hydroxymethyl)furan-2(3H)-one has been prepared in two steps from galactose. The first step potassium-2,3,4,5-tetrahedroxypentanoate was obtained in 64% yield and the title compound has been isolated in next step with 75% yield. The structures of the products were characterized by IR, 1H, 13C, mass and microanalysis study.

N- Maleilated chitosan was synthesized by reaction of chitosan with maleic anhydride (MA) in N, N-dimethyl formamide. N-Maleilated chitosan – g – (methyl methacrylate) co-polymer was prepared via free radical polymerization using ceric ammonium nitrate (CAN) as the initiator. The effect of polymerization variables including initiator concentration, monomer concentration and reaction temperature on grafting percentage were studied. It was found that the grafting yield and grafting efficiency were increased with increasing the polymerization variables and then decreased. The grafting was maximum at 1.6g of initiator (CAN), 2g of the monomer (Methyl methacrylate) at 70⁰c. The co-polymer obtained was confirmed by FTIR, XRD, TGA, DSC analysis. This graft co-polymer was used as an adsorbent in dye effluent treatment. It was more efficient than parent chitosan. Equilibrium sorption experiments were carried out. The experimental data was successfully fitted to the Langmuir adsorption isotherm.

The title organic–inorganic hybrid material, (C5N2ClH6)2[CdCl3.57(H2O)0.43].Cl0.43.H2O1.57, crystallizes in the non-centrosymmetric setting in the chiral space group P212121. Its simplified structure consists of edge sharing [CdCl4]2- units that are connected with each other to form infinite {[CdCl2Cl4/2]2-}n anionic chains; of 2-amino-5-chloropyridinium cations (two for every cadmium ion); and of one localized water molecule. Areas with additional electron density, adding up to 12 electrons each, are found in the form of narrow tubes that stretch along the direction of the a-axis, but no meaningful model for these regions could be devised and the electron density in there was instead corrected for by back-Fourier transformation methods. In the solid state structure one of the chlorine atoms of the tetrachlorocadmate units is partially replaced by a water molecule in a 0.568 (7) to 0.432 (7) ratio, with charge balance achieved through partial replacement of an interstitial water molecule by a chlorine ion. This leads to an actual formula for the compound of (C5N2ClH6)2[CdCl3.57(H2O)0.43].Cl0.43.H2O1.57 rather than the simplified (C5N2ClH6)2[CdCl4].2H2O. In the more prevalent cadmate units the metal centers have a distorted octahedral CdCl6 coordination sphere. In the remainder of the sites with one of the chlorines replaced by water, the coordination geometry is CdCl5(OH2) instead. The anionic and cationic units and the water molecules are connected through intricate O—H•••Cl, N—H•••Cl and N—H•••O hydrogen bonding interactions, with three of these being three-center interactions. The exocyclic N atom is an electron receiving center, which is consistent with features of imino resonance evidenced by bond lengths and angles. Results from solid state 13C and 15N CP–MAS NMR spectroscopy are in good agreement with the X-ray structure. Density functional theory calculations allowed for the assignment of the carbon peaks to the independent crystallographic sites.

The crystal structure of the title organic-inorganic hybrid material C7H7N2•NO3 has been determined by single crystal X-ray diffraction. The compound crystallizes in the noncentrosymmetric orthorhombic space group Pca21 with the lattice parameters a = 15.824 (1), b = 6.5461 (4), c = 16.215 (1) (6) Å, V = 1679.64 (18) Å3, and Z = 8. The framework is built upon layers parallel to (0 0 1) made up from the nitrate anions and the ammonium groups associated by N---H...O and N---H...N hydrogen bonds. The organic entities are interconnected via weak C-H…N hydrogen bonds involving the nitrogen atoms of the nitrile groups, leading to an infinite one-dimensional chains running along the a-axis. These chains are located alternatively on either side of the ionic layers. Results from solid state 1H, 13C and 15N spectroscopy are in good agreement with the X-ray structure. Density functional theory calculations allowed for the assignment of some carbon and nitrogen peaks to the independent crystallographic sites. The IR spectrum is dominated by the antisymmetric stretching mode of NO3-, which splits into two components indicating that the symmetry of the nitrate anion is lowered by interaction with the ammonium group.

The crystal structure of the title organic-inorganic hybrid material [C₃H₆N₃S₂]H₂PO₄, has been determined by single crystal X-ray diffraction. The compound crystallizes in the noncentrosymmetric orthorhombic space group Pna2₁ with the lattice parameters a = 7.662 (1), b = 26.553 (3), c =  4.4258 (6) Å, V = 900.4 (2) Å3, and Z = 4. The framework is built upon layers parallel to (0 1 0) made up from H₂PO₄^- entities associated by O---H...O strong hydrogen bonds. The organic cations are located between the layers and connect them via N-H…O and C-H…O hydrogen bonding network. The exocyclic C-N bond length reveals the presence of the imine and enamine tautomers in the starting reagent. Results from solid state ¹H, ³¹P, ¹³C and ¹⁵N spectroscopy are in good agreement with the X-ray structure. Density functional theory calculations allowed for the assignment of the carbon and nitrogen peaks to the independent crystallographic sites.

In recent years, preparation of polymer materials either soluble or insoluble in water with various functional groups has been developed, which can absorb metal ions in aqueous and non-aqueous media. In general, functionalized polymers for metal ion complexation can be prepared either by derivation of a basic polymer (precursor) with the desired ligand or by polymerization of the corresponding ligand derivatives. Among functionalized polymers, those containing EDTA have attracted much attention. EDTA with amino carboxylic acid groups can be introduced into or graft onto the backbone of polymer chains. Polymers bearing such groups can form stable complexes with various heavy metal ions. Therefore, we attempted to prepare new complexing polymer materials, which can be used in wastewater treatment. The synthesised random copolyesters were characterized by viscosity measurements, solubility studies, and spectral analysis. Thermal studies were also made on these copolyesters.