Adsorption of Copper (II) Ions in Aqueous Solution by a Natural Mouka Smectite and an Activated Carbon Prepared from Kola Nut Shells by Chemical Activation with Zinc Chloride (ZnCl₂)

The aim of this work was to test the adsorption efficiency of copper (II) ions in an aqueous solution on Natural Smectite (NS) and Activated Carbon (AC). The experiments carried out in batch mode made it possible to determine the stirring time, the adsorbent mass, the pH, the initial concentration of copper (II) ions, the isotherms and the adsorption kinetics. It appears that the stirring time was 15 minutes for the AC and 20 minutes for the NS. The adsorption was at maximum for the two adsorbents at optimum pH of 3.5 for a mass of 0.05 g each. The quantity of copper (II) ions adsorbed was 26.6 mg/L for NS and 36.6 mg/g for AC of a concentration of 600 mg/L each. The Langmuir isotherm was the one that best described the adsorption process for the two adsorbents. The adsorption kinetics obtained was that of the pseudo second-order for our two adsorbents. The results obtained showed that these two adsorbents were effective for the adsorption of copper (II) ions in an aqueous solution.

Synthesis, Characterization and DFT Studies of Two Zinc(II) Complexes Based on 2-Isopropylimidazole

Two novel coordination compounds, [Zn(L)2(OOCH)2] (1) and [Zn(L)3(OCHO)](OCHO)]·H2O (2) (where L = 2-isopropylimidazole, C6H10N2) have been prepared by reaction of 2-isopropylimidazole with zinc(II) formate at room temperature using toluene as solvent. These compounds were characterized by elemental and thermal analyses, IR, 1HNMR and 13CNMR spectroscopies, single crystal X-ray diffraction and DFT studies. The Zn centers in 1 and 2 adopt pseudo-tetrahedral coordination geometries. Compound 1 crystallizes in the monoclinic system P2/c space group whereas compound 2 crystallizes in the P-1 space group of the triclinic crystal system. Several types of hydrogen intra-/intermolecular interactions are observed in these materials and extend into a two-dimensional leaf like network in 1 and a two-dimensional lattice of rectilinear pillars in 2. Compounds 1 and 2 were also optimized and their frontier molecular orbitals, global reactivity descriptors, molecular electrostatic potential, natural bond orbitals were investigated using density functional theory (DFT). In fact the induced structural differences from complex 1 to complex 2 led to the reduction of the frontier molecular orbital energy gap by 1.338 eV and a decrease of the chemical hardness by 0.669 eV.

Synthesis, Rietveld Refinement and DFT Studies of Bis(4,5-dihydro-1<i>H</i>-benzo[g]indazole)silver(I) Hexafluorophosphate Complex Salt

The new salt bis(4,5-dihydro-1H-benzo[g]indazole)silver(I) hexafluorophosphate, [Ag(N2H10C11)2]PF6, has been synthesized in methanol at ambient temperature and characterized by elemental and thermal analyses, FTIR and 1HNMR spectroscopies, Rietveld refinement from powder diffraction data and DFT studies. The salt crystallizes in the triclinic space group P-1 with the parameters: a = 7.776 ?, b = 8.676 ?, c = 9.226 ?, α = 69.27° β = 89.86°, γ = 74.50°, V = 558.02 ?3, Z = 1. In the structure, the silver center is coordinated to two nitrogen atoms from two 4,5-dihydro-1H-benzo[g]indazole ligands, forming a centrosymmetric complex cation, [Ag(N2H10C11)2]+, with a linear coordination geometry around the silver center. The hexafluorophosphate ion, , acts as counter anion. The crystal packing is governed by N-H···F and C-H···F hydrogen bonds that interconnect the ionic constituents and Ag···F and Ag···π interactions help for the stabilization of the packing. The optimized structure was obtained at B3LYP/LanL2DZ level in the gas phase. The stability and reactivity of the structure were studied using respectively HOMO-LUMO gap and electronic global quantities (ionization potential (I) and electron affinity (A)) as descriptors.

Crystal Structure of Baryum Dicobalt Iron (III) Three (Orthophosphate) Belonging to <i>α</i>-CrPO<SUB>4</SUB>Family

The new compound, BaCo2Fe(PO4)3, has been synthesized by solid state reaction. The analysis by X-ray diffraction technique showed that it crystallizes in the orthorhombic system with the space group Imma. The structure is closely linked to that of α-CrPO4 type structure. In this structure, two oxygen atoms (O1, O2) are in general position and the others in special positions. The three-dimensional network of the crystal structure is made up of two types of chains running to [001] direction. The first chain is originated from two edge-sharing CoO6 octahedra leading to the formation of Co2O10 dimers that are connected to two PO4 tetrahedra by a common edge. The junction of FeO6 octahedra and PO4 tetrahedra sharing vertices allowed to built the second chain. These chains are linked together by common vertices of tetrahedra PO4 to form an open three-dimensional framework that delimits two types of tunnels parallel to [010] and [100] where the BaII cations are located. Indeed, each Barium cation is surrounded by eight oxygen atoms.

Synthesis, Structural Characterization and DFT Studies of Silver(I) Complex Salt of Bis(4,5-dihydro-1<i>H</i>-benzo[g]indazole)

A new silver complex salt [Ag(N2C11H10)2]NO3 (where N2C11H10 = 4,5-dihydro-1H-benzo[g]indazole), has been synthesized and characterized by elemental and thermal analyses, IR and 1HNMR spectroscopies, single crystal X-ray structure determination and DFT studies. Its molecular structure comprises of a silver center coordinated to two nitrogen atoms from two 4,5-dihydro-1H-benzo[g]indazole molecule giving rise to a cationic complex entity, [Ag(N2C11H10)2]+ with as counter ion. The bulk structure is consolidated by N–H…O, C–H…π, Ag…π and Ag…O intermolecular interactions, thus generating a pseudo-helical network. The optimized structure, frontier molecular orbitals (HOMO and LUMO) and global reactivity descriptors were investigated by performing DFT calculations.