The effect of uric acid on outdoor copper and bronze

Spent alumina catalyst (hereafter Al2O3) is a waste material from the petrochemical industry and primarily contains γ-alumina, beohmite, and organics. To reduce its negative impact on environment, spent alumina catalyst was characterized and utilized in this work to improve the removal efficiency of heavy metal ions from contaminated water in the model by immobilizing organic ligands on it. Dithizone (DTZ) and 2-amine-1-methylbenzimidazole (MAB) in an ethanol-water solution were impregnated in the pores of spent alumina catalyst according to the filling of 25% of the measured total pore volume. The sorption capacities of these new solid-phase sorbents (DTZ-Al2O3 and MAB-Al2O3) were evaluated by the sorption of heavy metal ions (Ni2+, Cd2+, and Zn2+) from model contaminated water. The highest sorption capacities for Ni2+ (0.37 mmol·g−1), Zn2+ (0.54 mmol·g−1) and Cd2+ (1.01 mmol·g−1) were noted for MAB-Al2O3. The MAB-Al2O3 sorbent has a similar sorption for metals in ternary solution with less selectivity but the DTZ-Al2O3 sorbent can adsorb Ni2+ and Zn2+ but not Cd2+. The effects of heavy metal ion concentration, pH, temperature, and contact time on the sorption capacities were studied. The sorption mechanism of heavy metal ions over the MAB-Al2O3 can be considered both the physical sorption of heavy metal ions on the surface of porous Al2O3 and a strong chemical reaction between heavy metal ions and the MAB-Al2O3 sorbent. In addition to the effective removal of heavy metal ions from contaminated water, the prepared solid-phase sorbents have several advantages: waste utilization, recyclability, scalability, low cost and easy preparation.

Ligand-immobilized spent alumina catalyst for effective removal of heavy metal ions from model contaminated water

The geometries and energetics of complexes of Li(+), Na(+), K(+), Be(2+), Mg(2+), and Ca(2+)metal cations with different possible uric acid anions (urate) were studied. The complexes were optimized at the B3LYP level and the 6-311++G(d,p) basis set. Complexes of urate with Mg(2+), and Ca(2+)metal cations were also optimized at the MP2/6-31+G(d) level. Single point energy calculations were performed at the MP2/6-311++G(d,p) level. The interactions of the metal cations at different nucleophilic sites of various possible urate were considered. It was revealed that metal cations would interact with urate in a bi-coordinate manner. In the gas phase, the most preferred position for the interaction of Li(+), Na(+), and K(+) cations is between the N(3) and O(2) sites, while all divalent cations Be(2+), Mg(2+), and Ca(2+) prefer binding between the N(7) and O(6) sites of the corresponding urate. The influence of aqueous solvent on the relative stability of different complexes has been examined using the Tomasi's polarized continuum model. The basis set superposition error (BSSE) corrected interaction energy was also computed for complexes. The AIM theory has been applied to analyze the properties of the bond critical points (electron densities and their Laplacians) involved in the coordination between urate and the metal cations. It was revealed that aqueous solvation would have significant effect on the relative stability of complexes obtained by the interaction of urate with Mg(2+) and Ca(2+)cations. Consequently, several complexes were found to exist in the water solution. The effect of metal cations on different NH and CO stretching vibrational modes of uric acid has also been discussed.

Theoretical Study of Interaction of Urate with Li+, Na+, K+, Be2+, Mg2+, and Ca2+ Metal Cations

Transition metal nitroprussides: Crystal and electronic structure, and related properties

Synthesis of uranyl(II), vanadyl(II) and zirconyl urate complexes, spectral, thermal and biological studies.

Acidic urates [Mn(HL)2] · H2O, [FeOH(HL)2]2 · 4H2O, [Co(HL)2(H2O)2] · 2H2O, and [Ni(HL)2(H2O)2] · 2H2O (H2L is uric acid) were synthesized and their structures and physicochemical properties were studied using IR spectroscopy, diffuse reflection spectroscopy, DTA, and magnetochemistry methods. The metals were shown to coordinate the urate anion through oxygen and nitrogen atoms. The [FeOH(HL)2]2 · 4H2O complex has a dimeric structure.

Synthesis and Properties of Acidic 3d-Metal Urates

The coordination compound [Co(L)3](OH)Cl(H3Ssal) · H2O (I) (L is benzhydrazide, and H3Ssal is 5-sulfosalycilic acid) has been synthesized and studied by IR spectroscopy and X-ray diffraction. Orange crystals are triclinic: a = 9.948(2) A, b = 12.288(3) A, c = 14.710(3) A, α = 109.39(3)°, β = 95.60(3)°, γ = 110.38(3)°, V = 1668.7(6) A3, Z = 2, space group $P\bar 1$ Structural units of compound I are complex CoL32+ cations, OH− and Cl− anions, sulfosalycilic acid molecules, and an H2O molecule disordered over two positions and linked to each other by hydrogen bonds. Phenyl rings participate in π-π-stacking interaction with the formation of centrosymmetric dimers.

Synthesis, crystal and molecular structure of [Co(L)3](OH)Cl · H3Ssal) · H2O, where L is benzhydrazide and H3Ssal is 5-sulfosalycilic acid

Coordination compounds of biurates with thiosemicarbazide [Mn(HL)2](Urat)2(H2O)2, [Co(HL)3](Urat)3(H2O)3, [Ni(HL)2](Urat)2(H2O)2, and [Ni(HL)2](Urat)2(H2O)4, where HL is thiosemicarbazide, and Urat is the anion of uric acid dissociated by the first step, were synthesized. The physicochemical properties and structures of the compounds were studied by IR and diffuse reflection spectroscopies, magnetochemistry, and DTA.

Coordination Compounds of 3d Metal Biurates with Thiosemicarbazide

Complex [Ni(Tsc)2](1.5-Nds) · 2H2O (I), where Tsc = thiosemicarbazide, NH2NHC(=S)NH2; 1,5-Nds2– is double deprotonated anion of 1,5-naphthalene disulfonic acid $$\rm{CH_{10}H_6(SO_3)_2^{2-}}$$
 was synthesized, characterized by IR spectroscopy, and studied by thermogravimetry and X-ray diffraction. Crystal I is built of complex cations [Ni(Tsc)2]2+, anions (Nds)2–, and crystallization water molecules. The Ni atom is coordinated along the vertices of the trans-square by two sulfur atoms and two nitrogen atoms of two bidentate chelating ligands Tsc. The structural units of crystal I are joined by a branched network of N–H···O and O–H···O hydrogen bonds with the participation of donors, namely, the hydrogen atoms of two NH2 groups and the NH group of complex cation [Cu(Tsc)]2+ and the H atoms of water molecules, and acceptors, namely, oxygen atoms of the sulfate group of anion 1,5-Nds2– and solvate water molecules.

Synthesis, Crystal, and Molecular Structure of bis(Thiosemicarbazide)Nickel(II) 1,5-Naphthalene Disulfonate Dihydrate Complex [Ni(Tsc)2](1,5-Nds) · 2H2O

The synthesis, IR and Raman spectroscopic study, and X-ray diffraction analysis of [Ni(HL1)3](L2)2 · 4H2O (I), where HL1 is phenylacetic acid hydrazide and L2 is the benzoate monoanion, have been performed. The structural units of a crystal of complex I are complex [Ni(HL1)3]2+ cations, (L2)– anions, and crystallization water molecules. The nickel atom is coordinated to the three oxygen atoms at octahedron apices and the three nitrogen atoms of three bidentate chelate (О, N) ligands HL1 in cis,trans-meredianal (fac) conformation. The structural units of a crystal of complex I are bonded by a branched network of О–Н···О and N–H···O hydrogen bonds.

T. V. Koksharova

Papers

Synthesis and Properties of Acidic 3d-Metal Urates

Synthesis, crystal and molecular structure of [Co(L)3](OH)Cl · H3Ssal) · H2O, where L is benzhydrazide and H3Ssal is 5-sulfosalycilic acid

Coordination Compounds of 3d Metal Biurates with Thiosemicarbazide

Synthesis, Crystal, and Molecular Structure of bis(Thiosemicarbazide)Nickel(II) 1,5-Naphthalene Disulfonate Dihydrate Complex [Ni(Tsc)2](1,5-Nds) · 2H2O

Nickel(II) tetraaqua bis(benzoate) tris(phenylacethydrazide) complex [Ni(HL 1 ) 3 ](L 2 ) 2 · 4H 2 O: Synthesis and crystal and molecular structure