Crystal structure,spectroscopic properties and density functional theory study of (Z)-1-[(2,4-dimethoxyphenylamino)methylene]naphthalen-2(1H)-one

The Schiff base (Z)-1-[(2,4-dimethoxyphenylamino)methylene]naphthalen-2(1H)-one was synthesized from the reaction of 2-hydroxy-1-naphthaldehyde with 2,4-dimethoxyaniline. The title compound has been characterized by FT-IR, UV-Vis and, X-ray single-crystal techniques. The present X-ray investigation shows that the compound exists in the keto-amine tautomeric form. Molecular geometry and vibrational frequencies of the compound in the ground state have been calculated using the density functional theory (DFT) with 6–311G(d, p) basis set and compared with the experimental data. The calculated results show that the optimized geometry is compatible with the crystal structure and the theoretical vibrational frequencies are in good agreement with the experimental values. Besides, molecular electrostatic potential (MEP), frontier molecular orbital analysis (HOMO-LUMO) and non-linear optical (NLO) properties of the compound were investigated using the same theoretical calculations.     

Big Heegner point Kolyvagin system for a family of modular forms

The principal goal of this paper is to develop Kolyvagin’s descent to apply with the big Heegner point Euler system constructed by Howard  for the big Galois representation \(\mathbb T \) attached to a Hida family \(\mathbb F \) of elliptic modular forms. In order to achieve this, we interpolate and control the Tamagawa factors attached to each member of the family \(\mathbb F \) at bad primes, which should be of independent interest. Using this, we then work out the Kolyvagin descent on the big Heegner point Euler system so as to obtain a big Kolyvagin system that interpolates the collection of Kolyvagin systems obtained by Fouquet for each member of the family individually. This construction has standard applications to Iwasawa theory, which we record at the end.     

A new ion imprinted polymer based on Ru(III)-thiobarbituric acid complex for solid phase extraction of ruthenium(III) prior to its determination by ETAAS

A new ruthenium ion imprinted polymer was prepared from the Ru(III) 2-thiobarbituric acid complex (the template), methacrylic acid or acrylamide (the functional monomers), and ethylene glycol dimethacrylate (the cross-linking agent) using 2,2′-azobisisobutyronitrile as the radical initiator. The ion imprinted polymer was characterized and used as a selective sorbent for the solid phase extraction of Ru(III) ions. The effects of type of functional monomer, sample volume, solution pH and flow rate on the extraction efficiency were studied in the dynamic mode. Ru(III) ion was quantitatively retained on the sorbents in the pH range from 3.5 to 10, and can be eluted with 4 mol L^?1 aqueous ammonia. The affinity of Ru(III) for the ion imprinted polymer based on the acrylamide monomer is weaker than that for the polymer based on the methacrylic acid monomer, which therefore was used in interference studies and in analytical applications. Following extraction of Ru(III) ions with the imprint and their subsequent elution from the polymer with aqueous ammonia, Ru(III) was detected by electrothermal atomic absorption spectrometry with a detection limit of 0.21 ng mL^?1. The method was successfully applied to the determination of trace amounts of Ru(III) in water, waste, road dust and platinum ore (CRM SARM 76) with a reproducibility (expressed as RSD) below 6.4 %.

Synthesis and Structural Characterization of a Binuclear Mixed‐Ligand (Salicylate and N,N‐diethylnicotinamide) Nickel(II) Complex,Its Magnetic Properties. [Ni2(µ‐Sal)4(Dena)2]H2O

The title complex of [Ni₂(µ‐Sal)₄(Dena)₂]H₂O, [( µ‐tetrakissalicylato‐κ‐O,O)(bis‐N,N‐diethylnicotinamide‐κ‐N)(binickel(II))]hydrate, C₄₈H₅₂Ni₂N₄O₁₆, has been synthesized and explained as structural using some elemental analysis, FT‐IR spectra, UV‐Vis reflectance, magnetic measurements, thermal analysis and x‐ray diffraction methods. The analysis results showed that the unit cell of complex includes two molecules Ni^II cation, four molecules salicylates as bridge and two molecules N,N‐diethylnicotinamide ligands, also there is one molecule hydrated aqua. The compound crystallizes in the monoclinic space group P2₁/c with the following unit‐cell parameters: a =13.6776(6) Å, b =10.5238(3) Å, c =21.8165(9), α=90.00°, β=126.546(3)°, γ=90.00º and Z=2. The compound [Ni₂(µ‐Sal)₄(Dena)₂]H₂O is a typical paddle‐wheel complex structure. Two Ni^II ions are bridged by four salicylate ligands (O2, O2ⁱ, O3, O3ⁱ, O5, O5ⁱ, O6 and O6ⁱ) using a µ‐COO^? coordination mode [symmetry code: (i) 1‐x, 1‐y, 1‐z]. Each Ni^II also coordinates to one nitrogen atom (N1 and N1ⁱ) from one N,N‐diethylnicotinamide ligand molecule in the axial position. The complex has strong paramagnetic properties.     

Effect of adsorption of polyhexamethyleneguanidine derivatives on the formation rate,morphology, and phase composition of carbonate deposits

It was found that introduction of polyhexamethylguanidines modified with carboxy and phosphonic groups into a saturated solution of calcium carbonate affects the formation rate, morphology, and phase composition of the deposits being formed, with crystals in the deposit becoming coarser and rhombic structures appearing. These phenomena were manifested to a greater extent when zinc complexes of polyelectrolytes are present in solution. An analysis of the phase composition of the deposit demonstrated that the presence of polyelectrolytes and their zinc complexes in solution leads to an increase in the amount of the calcite phase. The reason why the phase composition and morphology of the deposits changes is that polyelectrolytes and their complexes are adsorbed on the surface of carbonate deposits. The adsorption of polyelectrolytes on a calcium carbonate powder is described by the Langmuir isotherm and the formation of their zinc complexes leads to an increase in the adsorption equilibrium constant by more than a factor of 2, which is due to the change in the hydrophilic-lipophilic balance of macromolecules in complexation.     

Unusual Loss of Substituents in the Course of Cyclization of Tetrahydrobilines to Dihydroporphyrins

Metallo‐tetrahydrobiline rac‐ 8 was prepared to investigate its cyclization directed to the formation of N‐confused chlorins. To achieve the site‐directed selectivity of the cyclization, the 2‐position of rac‐ 2 was activated by an electron‐withdrawing cyano function and its 1‐position was blocked by a methyl group. In spite of this provision, the cyclization occurred at the apparently blocked 1‐position with loss or migration of the methyl substituent.     

Ligand-field photolysis of [Mo(CN)8]4- in aqueous hydrazine: trapped Mo(II) intermediate and catalytic disproportionation of hydrazine by cyano-ligated Mo(III,IV) complexes

The substitutional photolysis of K4[Mo(CN)8].2H2O in 98% N2H4.H2O has been investigated in detail. A molybdenum(II) intermediate, K5[Mo(CN)7].N2H4, is isolated in the primary stage of the reaction that involves the oxidation of N2H4 to N2, as evidenced by the analysis of evolving gases. The powder X-ray crystal structure of K5[Mo(CN)7].N2H4 indicates the pentagonal bipiramidal geometry of the anion and the presence of N2H4 in proximity to the CN(-) ligands. The salt is characterized by means of EDS, IR, UV-vis, and EPR spectroscopy as well as cyclic voltammetry measurements. The secondary stages of photolysis, involving the catalytic decomposition of N2H4 into NH3 and N2, lead to the formation of a molybdenum(IV) complex, [Mo(CN)4O(NH3)]2-. The monitoring of the amounts of evolving gases combined with UV-vis and EPR spectroscopic measurements at various stages of photolysis indicate that the molybdenum(III,IV) couple is catalytically active. The scheme of the catalytic decomposition of hydrazine is presented and discussed.     

Synthesis,characterization and electrochemistry of a new organosoluble metal-free and metallophthalocyanines

4-[2-(Phenylthio)ethoxy]phthalonitrile 3 was synthesized by nucleophilic displacement of nitro group in 4-nitrophthalonitrile with 2-(phenylthio)ethanol 1. The metal-free phthalocyanine 4 was prepared by the reaction of a dinitrile monomer with 2-(dimethylamino)ethanol. Ni(II), Co(II), Cu(I) phthalocyanines 5, 7, 8 were prepared by reaction of the dinitrile compound with the chlorides of Ni(II), Co(II), Cu(I) in DMAE. Zn(II) phthalocyanine 6, was prepared by reaction of the dinitrile compound with the acetates of Zn(II) in DMAE. Electrochemical behaviours of novel metal-free, Co(II) and Zn(II) phthalocyanines were investigated by cyclic voltammetry, potential differential pulse voltammetry techniques. The new compounds were characterized by a combination of IR, ¹H NMR, ¹³C NMR, UV–Vis, elemental analysis and MS spectral data.     

New long-chain-substituted polymeric metal-free and metallophthalocyanines by microwave irradiation: Synthesis and characterization

A tetranitrile monomer N,N-bis{2-[2-(3,4-dicyanophenoxy)ethoxy]ethyl}-4-methylbenzenesulfonamide (3) was synthesized by nucleophilic aromatic substitution of N,N-bis[2-(2-hydroxyethoxy)ethyl]-4-methylbenzenesulfonamide (1) onto 4-nitrophthalonitrile (2). The metal-free phthalocyanine polymer (4) was prepared by the reaction of a tetranitrile monomer 3 in 2-(dimethylamino)ethanol. Ni(II), Co(II) and Cu(II) phthalocyanine polymers were prepared by the reaction of the tetranitrile compound with the chlorides of Ni(II), Co(II) and Cu(II) in 2-(dimethylamino)ethanol (DMAE). The Zn(II)-phthalocyanine polymer was prepared by the reaction of the tetranitrile compound with the acetate of Zn(II) in DMAE. The new compounds were characterized by a combination of IR, ¹H NMR, ¹³C NMR, UV–Vis, elemental analysis and MS spectral data.     

Crystal structure and EPR studies of mixed ligand complex of cobalt(II) with saccharin and ethylisonicotine

The tetraaquabis(ethylisonicotinate)cobalt(II) disaccharinate, [Co(ein)2(H2O)4].(sac)2, (CENS), (ein: ethylisonicotinate and sac: saccharinate) complex has been synthesized and its crystal structure has been determined by X-ray diffraction analysis. The title complex crystallizes in monoclinic system with space group P2(1)/c and Z=2. The Co(II) cations present a slightly distorted CoN2O4 octahedral environment, with equatorially coordinated water molecules and axially pyridine N-bound ethylisonicotinate ligands. The magnetic environments of Cu2+-doped Co(II) complex have been identified by electron paramagnetic resonance (EPR) technique. Cu2+-doped CENS single crystals have been studied at room temperature in three mutually perpendicular planes. The calculated results of the Cu2+-doped CENS indicate that Cu2+ ion substitute with the Co2+ ion in the host lattice. The angular variations of the EPR spectra have shown that two different Cu2+ complexes are located in different chemical environments, and each environment contains two magnetically inequivalent Cu2+sites in distinct orientations occupying substitutional positions in the lattice and show very high angular dependence. The cyclic voltammogram of the title complex investigated in dimethylformamide (DMF) solution exhibits only metal centered electroactivity in the potential range -1.0-1.25V versus Ag/AgCl reference electrode.