Ethanol Salt Research Articles

Crystal structure, DFT, spectroscopic and biological activity evaluation of analgin complexes with Co(ii), Ni(ii) and Cu(ii).

Reaction of analgin (NaL) with Co(ii), Ni(ii) and Cu(ii) salts in ethanol affords complexes of the type [ML2], which were characterized by elemental analysis, FT IR, UV-Vis, EPR, TG/DTA, magnetic susceptibility and conductance measurements. The copper(ii) complex crystallizes in the orthorhombic Pbca space group. Analgin behaves as a mono-negatively tridentate ligand via pyrazolone O, sulfonate O and tertiary amino groups. The interaction of the tertiary nitrogen with M(n+) ions is the main factor which determines the stability of complexes as revealed from natural bond orbital analysis data, where the binding energy of [ML2] decreases with an increase in the bond length of the M-N bond. Time-dependent density functional theory calculations were applied in order to realize the electronic structures and to explain the related experimental observations. The anti-bacterial activity was studied on Staphylococcus aureus and Escherichia coli. Coordination of analgin to Ni(ii) and Cu(ii) leads to a significant increase in its antibacterial activity as compared with the Co(ii) complex.

A novel process for recovery of fermentation-derived succinic acid: Process design and economic analysis

Recovery and purification of organic acids produced in fermentation constitutes a significant fraction of total production cost. In this paper, the design and economic analysis of a process to recover succinic acid (SA) via dissolution and acidification of succinate salts in ethanol, followed by reactive distillation to form succinate esters, is presented. Process simulation was performed for a range of plant capacities (13-55 million kg/yr SA) and SA fermentation titers (50-100 kg/m(3)). Economics were evaluated for a recovery system installed within an existing fermentation facility producing succinate salts at a cost of $0.66/kg SA. For a SA processing capacity of 54.9 million kg/yr and a titer of 100 kg/m(3) SA, the model predicts a capital investment of $75 million and a net processing cost of $1.85 per kg SA. Required selling price of diethyl succinate for a 30% annual return on investment is $1.57 per kg.

Iodine(III)-Mediated Umpolung of Bromide Salts for the Ethoxybromination of Enamides

Using (diacetoxyiodo)benzene in conjunction with simple bromide salts in ethanol allows the regioselective ethoxybromination of a wide range of enamides, thus yielding highly versatile α-bromo hemiaminals, which can then be engaged in a broad array of transformations.

Ag nanowires: large-scale synthesis via a trace-salt-assisted solvothermal process and application in transparent electrodes

Ag nanowire (AgNW) films are receiving increasing attention as new transparent conductive films poised to replace indium tine oxide materials. However, coating of AgNW surfaces with polyvinylpyrrolidone (PVP) and other impurities during synthesis causes large contact resistance between the wires leading to low conductivities in the absence of additional treatments to fuse the overlapped AgNWs together. In the present work, we demonstrated a simple method to synthesize AgNWs by the reduction of AgNO3 using PVP as the reducing agent assisted by trace amounts of salts in ethanol. The shape and yield of the AgNWs depended significantly on the concentrations of these trace salts and on reaction temperatures. The silver nanowires were about 5–20 μm in length and showed a uniform diameter of about 70 nm. A detailed growth mechanism of the AgNWs has been proposed on the basis of the observations recorded by varying these synthesis parameters. Further, the AgNWs were used to form a transparent film, which without any additional treatments showed a sheet resistance of 10.4 Ω/sq and a transmittance of 81.9 % at 550 nm. The performance of the films was attributed to the trace amounts of residual impurities on the surface of the AgNWs and to the special V-shaped morphology of the wires prepared with the solvothermal process.

A facile approach to the synthesis of non-porous and microporous sub-micron spherical zirconia and alumina–zirconia solid solution

Amorphous monodisperse sub-micron spherical zirconia and alumina/zirconia solid solution particles were prepared by hydrolysis of zirconium and aluminum salts in ethanol. The heat-treatment process of the amorphous materials in air atmosphere at 500°C for 2h leaded to the production of non-porous zirconia and alumina/zirconia solid solution in tetragonal phase. The alkaline etching process of the as-prepared alumina/zirconia solid solution resulted in the formation of mono-modal microporous material with specific surface area of 125.0m2g−1 in comparison with 2.9m2g−1 for the parent material. Thermal analysis of the solid solution revealed that the incorporation of aluminum ions in the zirconia structure has decreased the phase transformation temperature from amorphous to crystalline structure. Moreover, optical study confirmed the presence of oxygen vacancy defect by substitution of tetravalent cations, Zr4+ by trivalent cations, Al3+ in zirconia lattice.

New trinuclear Schiff base complexes, Co–M–Co (M = Mn, Co), as molecular precursors for mixed oxides

Three new trinuclear symmetric derivatives of formula [Co2M(μ-salenph)2(μ-X)2] (salenph: N,N′-phenylenebis(salicylideniminato); 1, M=Mn, X=CH3COO−; 2, M=Mn, X=Cl−; 3, M=Co, X=CH3COO−), have been obtained by solvothermal reaction between [Co(salenph)] and the corresponding cobalt(II) or manganese(II) salts in ethanol. The complexes have been characterized by X-ray crystallography and magnetic susceptibility measurements. Complexes 1 and 3 are isomorphous and they show the X ligands bridging in opposite sides of the molecule having a trans coordination to the middle metal atom. On the contrary, compound 2 shows an unusual cis coordination of the chloride groups around the central manganese atom. The potential of the new complexes to act as single-source molecular precursors for mixed oxides is considered. The thermal decomposition of the three complexes indicates that they are completely converted to the crystalline spinel like oxides, Co3O4 and Co2MnO4. Magnetic properties of the obtained oxides have been investigated.

Features of reactions of quaternary salts derived from (4Z)-5-(bromomethyl)-2,2,6,6-tetra-methylhept-4-en-3-one. Synthesis of azolo[a]azepine and indolizine derivatives

The alkylation of 1-alkyl-2-methyl-1H-imidazoles, 1,2-dimethyl-1H-benzimidazole, and 2-R-pyridines by (4Z)-5-(bromomethyl)-2,2,6,6-tetramethylhept-4-en-3-one gives 1-alkyl-3-[(2Z)-2-tert-butyl-5,5-di-methyl-4-oxohex-2-en-1-yl]-2-methyl-1H-imidazol-3-ium, -1H-benzimidazol-3-ium, and 2-R-pyridinium bromides. Heating solutions of these diazolium salts in ethanol with potassium carbonate leads to 1,5-dihydroimidazo[1,2-a]azepinium and 5,10-dihydroazepino[1,2-a]benzimidazolium derivatives, while heating the pyridinium salts with triethylamine leads to indolizine derivatives. Heating solutions of quaternary salts derived from 1,2-dimethyl-1H-imidazole and 2-methylpyridine in acetic anhydride gives allylic rearrangement products, namely, 3-[(2Z)-2-tert-butyl-5,5-dimethyl-4-oxohex-1-en-1-yl]-1,2-dimethyl-1H-imidazol-3-ium and -2-methylpyridinium bromides, which under the action of base (MeONa for the diazolium salt and Et3N for the pyridinium salt) are converted into 1,5-dihydroimid-azo[1,2-a]azepinium and indolizine derivatives, respectively.

Convenient one-step synthesis of 4-unsubstituted 2-amino-4H-chromene-2-carbonitriles and 5-unsubstituted 5H-chromeno[2,3-b]pyridine-3-carbonitriles from quaternary ammonium salts

We have reported DBU catalyzed synthesis of 4-unsubstituted 2-amino-4H-chromene-2-carbonitriles in water under reflux. The attractive features of this process are mild reaction conditions, short reaction times, easy isolation of products and good yields. 5H-chromeno[2,3-b]pyridine-3-carbonitriles were obtained by refluxing excess of malononitrile and quaternary ammonium salts in ethanol in the presence of NaOH as catalyst. The mechanisms of these reactions are believed to involve the formation of the o-quinone methide intermediate.

Synthesis, Spectroscopic Characterization, and In Vitro Antimicrobial Studies of Pyridine-2-Carboxylic Acid N′-(4-Chloro-Benzoyl)-Hydrazide and Its Co(II), Ni(II), and Cu(II) Complexes

N-substituted pyridine hydrazide (pyridine-2-carbonyl chloride and 4-chloro-benzoic acid hydrazide) undergoes hydrazide formation of the iminic carbon nitrogen double bond through its reaction with cobalt(II), nickel(II), and copper(II) metal salts in ethanol which are reported and characterized based on elemental analyses, IR, solid reflectance, magnetic moment, molar conductance, and thermal analysis (TG). From the elemental analyses data, 1 : 2 metal complexes are formed having the general formulae [MCl2(HL)2] ·yH2O (where M = Co(II), Ni(II), and Cu(II), y = 1–3). The important infrared (IR) spectral bands corresponding to the active groups in the ligand and the solid complexes under investigation were studied. IR spectra show that ligand is coordinated to the metal ions in a neutral bidentate manner with ON donor sites. The solid complexes have been synthesized and studied by thermogravimetric analysis. All the metal chelates are found to be nonelectrolytes. From the magnetic and solid reflectance spectra, the complexes (cobalt(II), nickel(II), and copper(II)) have octahedral and square planner geometry, respectively. The antibacterial and antifungal activity's data show that the metal complexes have a promising biological activity comparable with the parent ligand against bacterial and fungal species.

Thermochemical water-splitting for H 2 generation using sol-gel derived Mn-ferrite in a packed bed reactor

This paper reports synthesis of Mn-ferrite using sol-gel technique, which involved the addition of Mn and Fe salts in ethanol followed by gelation using propylene oxide (PO). As-prepared gels were aged, dried and calcined rapidly upto different temperatures of 600 °C–900 °C and quenched in air. Calcined powders obtained were analyzed using x-ray diffraction, BET surface area analyzer, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The gels calcined rapidly upto 600 °C and quenched in air resulted into a phase pure Mn-ferrite with porous/nanoparticle morphology and higher SSA. The H 2 generation ability of the calcined powder was investigated by performing multiple thermochemical cycles in the Inconel packed bed reactor. In addition, the effects of several process parameters such as water-splitting temperature (T ws), regeneration temperature (T reg), regeneration time (t reg) and volumetric flow rate of water (v o) on H 2 generation ability of Mn-ferrite were investigated in detail.

A Mild Approach to the Synthesis of 4‐Amino‐8‐(arylamino)pyrimido[5,4‐d]pyrimidine 3‐Oxides

AbstractThe reaction of benzylhydroxylamine with 6‐cyanopurines leads to the formation of 7‐benzyloxy‐8‐imino‐7,8‐dihydropyrimido[5,4‐d]pyrimidines. The hydrochloride of these compounds, isolated upon addition of aqueous hydrochloric acid, is a convenient precursor of the pyrimido[5,4‐d]pyrimidine N‐oxides when a suspension of the salt is refluxed in ethanol or acetonitrile. Refluxing a solution of the same salt in ethanol, leads to the Dimroth‐rearranged product.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)

Design, structural elucidation, DNA interaction and antimicrobial activities of metal complexes containing tetraazamacrocyclic Schiff bases

Tetraazamacrocyclic Schiff bases, designed and synthesized from 3-hydroxy-4-nitrobenzylideneacetoacetanilide/3-hydroxy-4-nitrobenzylidene-o-acetoacetotoluidide and 1,2-diaminobenzene, are tetradentate ligands and form solid cationic complexes with CuII, NiII, CoII, ZnII, MnII, and VOIV salts in ethanol. Microanalytical data, magnetic moment, electronic, IR, Mass, 13C NMR, IH NMR, and electron spin resonance (ESR) techniques were used to characterize the synthesized compounds. Electronic absorption and IR spectra suggest that all the complexes are square planar, while the oxovanadium complexes are square pyramidal. Elemental analyses and mass spectra suggest that the general formula of the complexes is [ML]X (where L = L1 or L2, X = 2Cl− or ). Electrolytic behavior of the chelates was assessed from conductance data. The X-band ESR spectra of copper and oxovanadium complexes, recorded in dimethyl sulfoxide at 300 and 77 K, are discussed. Binding of the metal complexes with DNA has been investigated by spectroscopic, viscometric, and voltammetric methods. These data suggest that the complexes interact with DNA by intercalative binding. A comparative study of minimum inhibitory concentration values of the ligands and their complexes indicates that the complexes exhibit higher antimicrobial activity than the free ligands. The nuclease activity shows that the copper, manganese, nickel, and vanadium complexes cleave DNA through redox chemistry.

Fabrication of Continuous Conducting Gold Wires by Electrospinning

An innovative approach is developed to electrospin Au polymer wires, dissolving HAuCl4 salt in ethanol followed by addition of poly(acrylic acid) with several modifications in the conventional elec...

Polystyrene bead-based system for optical sensing using spiropyran photoswitches

Spiropyran derivatives have been immobilised on the surface of polystyrene microbeads using different immobilisation strategies. These functionalised polymeric beads can be reversibly switched between the colourless inactive spiropyran (SP) and highly coloured (purple) active merocyanine (MC) forms using low power light sources, such as light-emitting diodes (LEDs). A UV LED (375 nm) is used for the SP → MC conversion, and a white LED (430–760 nm) for the reverse MC → SP conversion. The photochromic behaviour of the coated beads has been characterised using different LEDs and reflection spectroscopy, employing optic fibres and an in-house-designed holder. Investigations into the metal-ion binding behaviour of the spiropyran-modified microbeads have shown that Cu2+ ions cause an appreciable colour and spectral change when brought into contact with the beads in the MC form, suggesting that a significant interaction is occurring. However, the Cu2+ ions can be completely expelled by photonic-conversion of the beads into the inactive SP form using a white LED. This sequence has been successfully repeated six times, suggesting that it is possible to cycle through activation of the functionalised beads from a non-binding to a binding form (SP → MC) using a UV LED, allow binding with Cu2+ ions to occur, and subsequently, expel the bound ions and regenerate the passive SP surface using a white LED. Other metals, such as calcium, do not cause any appreciable colour or spectral change over the same concentration range and in the presence of the same anion (final concentration 7.1 × 10−4 M nitrate salt in ethanol). The system is therefore self-indicating in terms of whether the active MC or inactive SP forms are present, and whether Cu2+ ions are bound to the MC form. In principle, therefore, these functionalised beads could form the basis of a photoswitchable stationary phase for metal ion binding and detection: irradiation of the stationary phase with UV LEDs causes retention of guest species due to the presence of the MC form, while subsequent exposure to white LEDs causes release of guest species into the mobile phase.

Synthesis and structural characterization of cobalt(II) and zinc(II) complexes with 2-(indazol-1-yl)-2-thiazoline (TnInA). X-ray characterization of [CoCl 2(TnInA) 2] · C 2H 6O and [(M)(TnInA) 2(H 2O) 2](NO 3) 2 (M = Co, Zn)

Several complexes of 2-(indazol-1-yl)-2-thiazoline (TnInA) with the divalent ions Co and Zn have been synthesized by the direct combination of the ligand and the metal chloride or nitrate hydrated salts in ethanol. These complexes have been characterized by a variety of physical–chemical techniques. Moreover, the structures of [CoCl 2(TnInA) 2] · C 2H 6O ( 1) and [(M)(TnInA) 2(H 2O) 2](NO 3) 2 (M = Co, 3; Zn, 4) were determined by single-crystal X-ray diffraction. In all the complexes, the ligand TnInA bonds to the metal ion through the indazole and thiazoline nitrogen atoms. In complex 1 the environment around the cobalt ion may be described as a distorted octahedron with two TnInA ligands and two chlorine ligands. Compounds 3 and 4 are isostructural with a distorted octahedral geometry around the metal center, being linked to two water molecules and two TnInA ligands. However, in complex [ZnCl 2(TnInA)] ( 2) the zinc atom is four-coordinated with a probable tetrahedral environment with two chloro ligands and one TnInA ligand bonded to the metal ion.

Preparation of α-LiFeO 2-based cathode materials by an ionic exchange method

β-FeOOH prepared with an enhanced hydrolysis method had been subjected to H +/Li + exchange with various lithium salts in ethanol for various duration. The effects of the kind of lithium salt used and the duration of ionic exchange on the composition, the crystalline structure, and the electrochemical properties of the prepared powders were investigated. It was found that α-LiFeO 2 can be prepared from β-FeOOH by an ionic exchange reaction with LiOH in ethanol at 85 °C. α-LiFeO 2 powders so prepared show electrochemical active properties with reversible capacity of 65–80 mAh g −1. The in situ XRD patterns of the cycled α-LiFeO 2 cathode revealed that the crystalline structure remains unchanged while the lattice of cubic decreases and increases periodically upon charge/discharge cycling. The results of XANES suggest that the electrochemical reaction of the Fe 3+/Fe 2+ redox couple occurs as the prepared α-LiFeO 2 electrode is charge/discharge cycled.

Synthesis of Schiff bases of naphtha[1,2-d]thiazol-2-amine and metal complexes of 2-(2′-hydroxy)benzylideneaminonaphthothiazole as potential antimicrobial agents

A series of 2-benzylideneaminonaphthothiazoles were designed and synthesized incorporating the lipophilic naphthalene ring to render them more capable of penetrating various biomembranes. Schiff bases were synthesized by the reaction of naphtha[1,2-d]thiazol-2-amine with various substituted aromatic aldehydes. 2-(2'-Hydroxy)benzylideneaminonaphthothiazole was converted to its Co(II), Ni(II) and Cu(II) metal complexes upon treatment with metal salts in ethanol. All the compounds were evaluated for their antibacterial activities by paper disc diffusion method with Gram positive Staphylococcus aureus and Staphylococcus epidermidis and Gram negative Escherichia coli and Pseudomonas aeruginosa bacteria. The minimum inhibitory concentrations of all the Schiff bases and metal complexes were determined by agar streak dilution method. All the compounds moderately inhibited the growth of Gram positive and Gram negative bacteria. In the present study among all Schiff bases 2-(2'-hydroxy)benzylideneaminonaphthothiazole showed maximum inhibitory activity and among metal complexes Cu(II) metal complex was found to be most potent. The results obtained validate the hypothesis that Schiff bases having substitution with halogens, hydroxyl group and nitro group at phenyl ring are required for the antibacterial activity while methoxy group at different positions in the aromatic ring has minimal role in the inhibitory activity. The results also indicated that the metal complexes are better antibacterial agents as compared to the Schiff bases.

Cobalt(II) complexes of various thiosemicarbazones of 4-aminoantipyrine: syntheses, spectral, thermal and antimicrobial studies

An interesting series of cobalt(II) complexes of the new ligands: 4[N-(benzalidene)amino]antipyrinethiosemicarbazone (BAAPTS), 4[N-(2′-hydroxy-benzalidene)amino]antipyrinethiosemicarbazone (HBAAPTS) and 4[N-(2′-hydroxy-1′-naphthalidene)amino]antipyrinethiosemicarbazone (HNAAPTS) were synthesized by reaction with Co(II) salts in ethanol. The general stoichiometry of the complexes was found to be [CoX2(H2O)(L)] and [Co(L)2](ClO4)2, where X = Cl, NO3, NCS or CH3COO and L = BAAPTS, HBAAPTS or HNAAPTS. The complexes were characterized by elemental analysis, molar conductivity measurement, molecular weight determination, magnetic moments at room temperature, infrared and electronic spectra. All the thiosemicarbazones behave as neutral tridentate (N, N, S) donor ligands. The conductivity measurements in PhNO2 solution indicated that the chloro, nitrato, thiocyanato and acetate complexes are essentially non-electrolytes, while the perchlorate complexes are 1:2 electrolytes. Thermogravimetric studies were performed for some representative complexes and the decomposition mechanism proposed. Antibacterial and antifungal properties of the ligands and their cobalt(II) complexes have also been examined and it has been observed that the complexes are more potent bactericides than the ligand.

Gas Chromatography on Self-Assembled, Single-Walled Carbon Nanotubes

High-performance stationary phases, which provide high resolutions and are stable at high temperatures, are of significant importance in gas chromatographic analysis. Carbon nanotubes are nanosized carbon-based sorbents that have a high surface area and a large aspect ratio and are known to be stable at high temperatures. It is, therefore, conceivable that gas chromatography can benefit from their unique properties. This paper reports gas chromatography separations in an open tubular format on self-assembled, single-walled carbon nanotubes (SWNTs) inside silica-lined steel capillary tubing. A SWNT film with an average thickness of 300 nm was self-assembled by a unique, single-step, catalytic chemical vapor deposition (CVD) process consisting of dissolved cobalt and molybdenum salts in ethanol. A variety of organic compounds with varying polarity were separated at high resolution, and the column efficiency demonstrated approximately 1000 theoretical plates/m. Comparison of capacity factors' and isosteric heats of adsorption with a packed column containing a commercial sorbent (Carbopack C) showed comparable results. This demonstrated high capacity and strong sorbate-sorbent interactions on the SWNT phase. Evaluation of the McReynolds constants suggested that the SWNT was a nonpolar phase.

Synthesis, Spectral, and Cyclic Voltammetric Studies of Tetraaza Copper(II), Oxovanadium(IV), and Zinc(II) Complexes Derived from 1,2‐(Diimino‐4′‐antipyrinyl)‐1,2‐diphenylethane and para‐Substituted Anilines

Tetraaza acyclic Schiff bases, prepared from 1,2‐(diimino‐4′‐antipyrinyl)‐1,2‐diphenylethane and p‐substituted anilines, act as tetradentate ligands and form solid cationic solid complexes with Cu(II), Zn(II), and VO(IV) salts in ethanol. Microanalytical data, magnetic susceptibility measurements, IR, UV‐VIS, mass, 1H and 13C NMR, and ESR spectral techniques were used to characterize the structures of synthesized compounds. IR and UV‐VIS spectra of the complexes suggest that all the copper complexes exhibit square–planar geometry while the oxovanadium complexes are of square–pyramidal geometry. Mass, 1H and 13C NMR spectra of the Schiff bases and their complexes suggest that the general formula of the complexes is [ML]Y (where L = L1, L2 or L3, Y = Cl2 or SO4). Electrolytic behaviour of the chelates was assessed from their higher conductance data. Monomeric nature of the chelates was confirmed from their magnetic susceptibility values. Redox studies by cyclic voltammetry of copper complexes in MeCN suggest the existence of unusual oxidation states such as Cu(III), Cu(I), and Cu(0) which are stabilized by the ligand systems. The cyclic voltammogram of the oxovanadium complexes in MeCN shows two quasi‐reversible peak for the VO(IV)/VO(V) and VO(IV)/VO(III) couples. The X‐band ESR spectra of copper and oxovanadium complexes in DMSO solution at 300 and 77 K were recorded and their salient features are discussed.