Vibrational spectroscopic studies on the en-Td-type benzene clathrates: M(ethylenediamine)M′(CN)4·2C6H6 (M=Mn or Cd,M′=Cd or Hg)

IR spectra of Mn(en)M(CN)₄·2C₆H₆ (M=Cd or Hg), and IR and Raman spectra of Cd(en)M(CN)₄·2C₆H₆ (M=Cd or Hg) clathrates are reported. The spectral features suggest that the first two compounds are similar in structure to the later two Td-type clathrates.     

PAN-based activated carbon nanofiber/metal oxide composites for CO2 and CH4 adsorption: influence of metal oxide

In the present study, we successfully prepared two different electrospun polyacrylonitrile (PAN) based-activated carbon nanofiber (ACNF) composites by incorporation of well-distributed Fe₂O₃ and Co₃O₄ nanoparticles (NPs). The influence of metal oxide on the structural, morphological, and textural properties of final composites was thoroughly investigated. The results showed that the morphological and textural properties could be easily tuned by changing the metal oxide NPs. Even though, the ACNF composites were not chemically activated by any activation agent, they presented relatively high surface areas (S_BET) calculated by Brunauer–Emmett–Teller (BET) equation as 212.21 and 185.12 m²/g for ACNF/Fe₂O₃ and ACNF/Co₃O₄ composites, respectively. Furthermore, the ACNF composites were utilized as candidate adsorbents for CO₂ and CH₄ adsorption. The ACNF/Fe₂O₃ and ACNF/Co₃O₄ composites resulted the highest CO₂ adsorption capacities of 1.502 and 2.166 mmol/g at 0 °C, respectively, whereas the highest CH₄ adsorption capacities were obtained to be 0.516 and 0.661 mmol/g at 0 °C by ACNF/Fe₂O₃ and ACNF/Co₃O₄ composites, respectively. The isosteric heats calculated lower than 80 kJ/mol showed that the adsorption processes of CO₂ and CH₄ were mainly dominated by physical adsorption for both ACNF composites. Our findings indicated that ACNF-metal oxide composites are useful materials for designing of CO₂ and CH₄ adsorption systems.     

Electrochemical,Spectroelectrochemical, and Electrocatalytic Dioxygen Reducing Properties of Peripheral Tetra-2,6-dimethoxyphenoxy Substituted Phthalocyanines

By using of peripherally tetrakis-2,6-dimethoxyphenoxy substituted Co(II), Fe(III), and Mn(III) phthalocyanines was observed to extend the redox richness of the phthalocyanine ring with the addition of reversible metal-based electron transfer couples to the phthalocyanine ring-based electron transfer processes in solution. The emergence of highly steady anionic and cationic redox species with clear spectral and colour changes both in solution and in the film during in situ spectroelectrochemical and in situ electrocolorimetric measurements pointed out their applicability as electrochromic materials. Furthermore, the phthalocyanine complexes demonstrated strong interaction with dioxygen and thus, high electrocatalytic enforcement for its reduction.     

A Robust Analytical Approach for the Identification of Specific Protein Carbonylation Sites: Metal-Catalyzed Oxidations of Human Serum Albumin

The formation of protein carbonyls in the metal-catalyzed oxidation of human serum albumin (HSA) is characterized using a new analytical approach that involves tagging the modification site with multiple hydrazide reagents. Protein carbonyl formation at lysine and arginine residues was catalyzed with copper and iron ions, and the resulting oxidation patterns in HSA are contrasted. A total of 18 modification sites were identified with iron-ion catalysis and 14 with copper-ion catalysis. However, with the more stringent requirement of identification with at least two tagging reagents, the number of validated modification sites drops to 10 for iron and nine for copper. Of the 14 total validated sites, there were only five in common for the two metal ions. The results illustrate the value of using multiple tagging agents and highlight the selective and specific nature of metal-catalyzed protein oxidations.     

Synthesis and non-aqueous medium titrations of some new 4-benzylidenamino-4,5-dihydro-1H-1,2,4-triazol-5-one derivatives

The synthesis of 3-alkyl(aryl)-4-(3-ethoxy-4-hydroxybenzylidenamino)-4,5-dihydro-1H-1,2,4-triazol-5-ones 3 from the reactions of 3-alkyl(aryl)-4-amino-4,5-dihydro-1H-1,2,4-triazol-5-ones 2 with 3-ethoxy-4-hydroxybenzaldehyde is described.The acetylation and methylation reactions of the compounds 3 giving compounds of type 4 and 5, respectively, were investigated. The newly synthesized compounds were characterized using elemental analyses and IR, (1)H-NMR, (13)C-NMR and UV spectral data.In addition, to investigate the effects of solvents and molecular structure upon acidity,compounds 3 were titrated potentiometrically with tetrabutylammonium hydroxide in four non-aqueous solvents (isopropyl alcohol, tert-butyl alcohol, acetonitrile and N,N-dimethylformamide). The half-neutralization potential values and the corresponding pKa values were determined for all cases.     

Synthesis,Spectrothermal Behaviour and Molecular Structure of Aquaorotatotriethanolaminenickel(II) Monohydrate

The aquaorotatotriethanolaminenickel(II) monohydrate, [Ni(HOr)(H₂O)(tea)]·H₂O ( 1 ), was synthesized and characterized by means of elementel analysis, IR and UV‐Vis, spectroscopy, magnetic susceptibility, thermal analysis and X‐ray diffraction techniques. The nickel ion in [Ni(C₅H₂N₂O₄)(H₂O)(N(C₂H₄OH)₃)] is chelated to the deprotonated N3 pyrimidine atom and to the carboxylate oxygen atom of the bidentate orotate dianion, and to the one nitrogen and two oxygen atoms of the tridentate triethanolamine molecule and its octahedral geometry is completed by an aqua ligand. It crystallizes in the monoclinic system, space group P2₁/c with lattice parameters a = 7.1528(5) Å, b = 19.4903(14) Å, c = 11.8085(8) Å, β = 106.237(5)°, V = 1580.55(19) ų, Z = 4. An extensive three dimensional network of O_w‐H…O, N‐H…O and O‐H…O hydrogen bonds, π‐π and π‐ring interactions are responsible for crystal stabilization. The decomposition reaction take places in the temperature range 20‐1000 °C in the static air atmosphere. Thermal decomposition of 1 proceeds in three stages.     

A new decavanadate polyoxovanadate nanocluster: synthesis,characterization and rapid adsorption of methylene blue

A new decavanadate polyoxovanadate nanocluster, [2-ampH]₆[V₁₀O₂₈]?2H₂O (1), was synthesized through reaction between ammonium vanadate and 2-aminopyridine at pH = 2. Nanocluster 1 was characterized by IR, elemental analysis, and X-ray crystallography. 1 was found to adsorb and desorb dyes and may have widespread application in wastewater treatment. The utility of 1 for adsorption of methylene blue was studied. The adsorbed dyes can be easily desorbed, and 1 has full efficiency after five cycles.     

Complexes of iron(III) salen and saloph Schiff bases with bridging 2,4,6-<Emphasis Type="BoldItalic">tris</Emphasis>(2,5-dicarboxyphenylimino-4-formylphenoxy)-1,3,5-triazine and 2,4,6-<Emphasis Type="BoldItalic">tris</Emphasis>(4-carboxyphenylimino-4′-formylphenoxy)-1,3,5-triazine

Four new trinuclear Fe(III) complexes involving tetradenta Schiff bases N,N ¹ -bis(salicylidene) ethylenediamine-(salenH₂) or bis(salicylidene)-o-phenylenediamine-(salophH₂) with 2,4,6-tris(2,5-dicarboxyphenylimino-4-formylphenoxy)-1,3,5-triazine (DCPI-TRIPOD) or 2,4,6-tris(4-carboxyphenylimino-4′-formylphenoxy)-1,3,5-triazine (CPI-TRIPOD) have been synthesized and characterized by means of elemental analysis carrying out ¹H-n.m.r., i.r. spectroscopy, thermal analyses and magnetic susceptibility measurements. The complexes can also be characterized as high-spin distorted octahedral Fe^III bridged by carboxylic acids. The tricarboxylic acids play a role as bridges for weak antiferromagnetic intramolecular exchange.     

Synthesis, characterization and electrical properties of novel mono- and cofacial bisphthalocyanines bridged with four [1a,8b-dihydronaphtho[b]naphthofuro[3,2-d]furan-7,10-diyl] units

Novel mono phthalocyanines and cofacial bisphthalocyanines were synthesized from 4,4′-(1a,8b-dihydronaphtho[b]naphthofuro-[3,2-d]furan-7,10-diyl)bis(oxy)diphthalonitrile 1. The products were characterized by elemental analysis, UV-vis, IR, ¹H NMR and mass spectroscopy. Both the direct current (dc) and alternating current (ac) electrical properties of the product films were investigated as a function of temperature in the frequency range 40-10⁵ Hz. It was observed that the ac response of the films can be represented by the ω^s law. The temperature dependence of dc conductivity showed typical Arrhenius behavior for all compounds.