Classical chemical sciences
Multi-functionalized xanthenes were synthesised using arylaldehydes and 1,3-dicarbonyl compounds through multi-component reactions using acetic acid as the catalyst and all these newly synthesized compounds have been characterized using 1H NMR, 13C NMR and IR spectral data.
Keywords: Multicomponent reactions; acetic acid; benzoxanthenes
Six chelate complexes of 4-hydroxy-6-methyl-3-((Z)-4-methylphenylazo)-2H-pyran-2-one (HL) ligand with Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) were synthesized and characterized by elemental analysis, magnetic susceptibility measurements, electronic, 1H, 13C NMR and IR spectral studies. The ligand is coordinated to the metals through its deprotonated pyrane-oxygen and the azo-group. Mn(II), Co(II), Cu(II) and Ni(II) complexes have octahedral geometry around the central atoms. The molar conductance measurements on chloride-ion containing Zn(II) and Cd(II) complexes confirmed that chloride ions are bound in the coordination sphere, and the most probable geometry around the central atoms is likely to be tetrahedral.
Keywords: azo dye, metal complexes, 4-hydroxy-6- methyl-3-((Z)-4-methylphenylazo)-2H-pyran-2-one ligand
Water/n-propanol/ionic surfactant /phenylacetylene micellar systems were formulated. The surfactants were the anionic, sodium dodecyl sulfate and the cationic cetyltrimethylammonium bromide. The ratio (w/w) of n-propanol/surfactant equals 2/1. The extent of the micellar region as function of temperature was determined. The particle hydrodynamic diameter of the oil-in-water micellar systems measured using dynamic light scattering and was found to decrease with temperature. In the diluted region, nanoemulsions systems were observed. Hydration of alkynes found to be highly influenced from the ionic nature of the surfactant. Cationic surfactants accelerate the addition of water to alkynes while anionic surfactants decease the reaction rate.
Keywords: phase behavior, nanoemulsions, hydrodynamic diameter, dynamic light scattering, hydration of alkynes
The reaction of acetoacetanilide (1) with cyclohexanone (2) gave compound 3 which it was reacted with the active methylene reagents 4a, b afforded cyclohexylidene derivatives 5a, b. The latter products were reacted with elemental sulfur in presence of basic catalyst to produce thiophene derivatives 6a, b. Also compound 1 reacted with diazonium salts 7a, b then compounds 8a, b were produced respectively, compounds 8a, b were directed toward the reaction with malononitrile (4a), ethyl cyanoacetate (4b) in either ammonium acetate or piperdine to form compounds 9a-d and 10a-d respectively, also compounds 8a, b reacted with either phenylisothiocanate (11) afforded compounds 13a, b or hydrazine derivatives 14a, b to produce compounds 15a-d. The newly synthesized compounds were evaluated for antitumor activity.
Keywords: pyrazol, pyridazine, thiophene, 1, 2, 4 triazine, cytotoxic activity
Salicylaldehyde thiosemicarbazone complexes of Pd(II), Cu(II) and Ru(III) have been characterized by elemental analyses, molar conductance, infrared, NMR, electronic spectra and thermal analyses. The data show the formation of two different types of complexes with 1:1 and 1:2 metal:ligand stoichiometries. The dc electrical conductivity of the ligand and the complexes was measured at varying temperatures. The results obtained were explained and discussed in terms of proposed semicondutive behaviour of the complexes and a probable occurrence of phase transition. The activation energies were calculated for the ligand and the complexes.
Keywords: use the Keywords style for the list of keywords, separating with a comma each items
The protiated (H2O) and deuteriated (D2O) crystallohydrates of quinoline N-oxide, 2-methylquinoline N-oxide and 4-methylquinoline Noxide demonstrate different behavior at ambient conditions, namely, the deuteriated dihydrates undergo solid state transformation into crystalline anhydrous or hemihydrate forms, while protiated dihydrates loss 3D periodicity. In attempts to explain this phenomenon, the crystal structures of the six compounds – namely, quinoline N-oxide and quinoline N-oxide dihydrate, 2-methylquinoline N-oxide hemideuteriohydrate and 4-methylquinoline N-oxide dihydrate, 4-methylquinoline N-oxide and 4-methylquinoline N-oxide dihydrate – were analyzed.
Keywords: quinoline N-oxide; 2-methylquinoline-N-oxide; 4-methylquinoline-N-oxide; crystallohydrates ; deuteriohydrates; dehydration, crystal structure; powder X-ray diffraction
Green synthesis of novel compounds 4-(2-carboxybenzamido)-2-hydroxybenzoic acids 3a-3e and 4-(1,3-dioxoisoindolin-2-yl)-2- hydroxybenzoic acids 4a-4e have been developed in good yields which were analogues of p-aminosalicylic acid (used as anti-tuberculosis agent)
Keywords: phthalic anhydrides; p-aminosalicylic acid; anti-tuberculosis agents; 4-(2-carboxybenzamido)-2-hydroxybenzoic acids; 4-(1,3-dioxoisoindolin-2-yl)-2-hydroxybenzoic acids
A six-coordinated Ni(II) complex, bis(O-ethylxanthato)bis(3,5-dimethylpyridine)nickel(II), [C20H28N2NiO2S4], has been synthesized by the reaction of bis(O-ethylxanthato)nickel(II) with 3,5-dimethylpyridine in acetone. The Ni atom in the title complex is octahedrally coordinated within a trans-N2S4 donor set, with the Ni atom located on a centre of inversion. The structure of the title compound was elucidated by a single-crystal X-ray diffraction method. The compound crystallizes in the triclinic space group P-1 with unit-cell parameters: a = 7.1750(3) Å, b = 9.3864(5) Å, c = 9.6914(4) Å and α = 84.962(4)°, β = 73.017(4)°, γ = 75.172(4)°. The crystal structure was solved by direct methods and refined by full-matrix least-squares procedures to a final R-value of 0.0238 for 2162 observed reflections. The asymmetric unit comprises half a molecule. The pyridine ring is coplanar, and is held almost perpendicular to the dithiocarbonato group. Molecules in the crystal are packed together to form layers.
Keywords: Octahedral coordination, direct methods, crystal structure; bis(O-ethylxanthato)bis(3,5-dimethylpyridine)nickel(II)
A simple and efficient synthesis of 4-allyl-5-(4-R1)-phenylthiomethyl-1,2,4-triazole-3-yl-mercaptoacetic acid derivatives 7a-l is described herein. This technique uses a direct alkylation 3-mercapto-4-allyl-5-(4-R1)-phenylthiomethyl-1,2,4-triazoles 5a-b, with substituted chloracetic acid anilides 6a-k, and 4'-bromo-2-chloroacetophenone 6l. The probability of anti-ulcer activity of the newly synthesized substances 5a-b and 7a-l was simulated by the computer program PASS and docking studies. The findings show that all substances of this group may be used for the treatment NSAID-inducеd ulcers.
Keywords: synthesis, anti-ulcer activity, rational drug design, triazoles
The structure of the thermal alfa->ß benzoins isomerization product, 2-hydroxy-2-(4’’-chlorophenyl)-1-(5’-N,N-dimethylhydrazonofuryl-2’)- ethanone-1 has been proved by the XRD study. The possibility of the Me2NN=CH-substituent conjugation with the carbonyl group via the furane ring take place due to the overall planarity this molecule fragment.
Keywords: ß-benzoin, structure, isomerization
A series of metal (Cr(III), Fe(III), Mn(II), Co(II), Ni(II), Cu(II) and Zn(II)) complexes with 4-[(Z-(4-hydroxy-6-methyl-2-oxo-2H-pyran-3- yl]-1-methyl-2-phenyl-1,2-dihydro-3H-pyrazol-3-one were prepared by azo coupling of diazotised 4-aminoantipyrine with 4-hydroxy-6- methyl-2-pyranone. The free ligand and its metal complexes were fully characterized on the basis of elemental analyses and 1H NMR, FTIR and UV-Visible spectroscopy. The keto-enol tautomer azo ligand [HL] was a mixture of E and Z isomers as suggested by 1H NMR and FTIR spectroscopy. The chelating properties of the new azo ligand were studied towards Cr(III), Fe(III), Co(II), Ni(II), Cu(II) and Zn(II) ions, and the spectral data revealed that the nitrogen and oxygen atoms of –N=N-, C=O and –OH groups participated in bonding with the metal ions. The study of NMR, IR and electronic spectra indicated an octahedral structure for all metal complexes except zinc(II) complex, which has the tetrahedral structure.
Keywords: Azo dyes derived from 4-hydroxy-6-methyl-2-pyranone; transition metal complexes; synthesis
Three coordination compounds with urea (CO(NH2)2) ligands, namely [Cr(urea)6](ClO4)3, [Cr(urea)6](BF4)3, and [Cr(urea)6]Cl3 were investigated. In the temperature range of 130–320 K only the first two aforementioned complexes undergo one solid phase transition at: Th C =298.4 K and Th C=255.4 K (on heating), respectively. X-ray single crystal diffraction at 293 K demonstrates that [Cr(urea)6](BF4)3 crystallises in the trigonal crystal system (R-3c space group) and is isostructural with the other two title compounds. Both the BF4 anions and CO(NH2)2 ligands are in the high temperature phase dynamically disordered. [Cr(urea)6](ClO4)3, [Cr(urea)6](BF4)3 and [Cr(urea)6]Cl3 are thermally stable up to ca. 500, 470 and 440 K, respectively, in argon atmosphere. [Cr(urea)6](ClO4)3 decomposes explosively at ca. 550 K. [Cr(urea)6](BF4)3 decomposes in three main stages with creation of Cr2O3 as a final product of decomposition at 1250 K. Whereas [Cr(urea)6]Cl3 decomposes in two main stages. The mixture of Cr, CrCl3 and ClCrNH is created at 1270 K as a product of decomposition.
Keywords: hexakis(urea-O)chromium(III) complexes; crystal structure; vibrational and electronic spectroscopy; phase transition; thermal decomposition
The title compound, N-hydroxy-4-phenylbut-3-en-2-imine [C10H11NO], was synthesized by reacting benzylideneacetone with hydroxylamine hydrochloride in the presence of base. The structure of the compound was characterized by single crystal XRD data. It crystallizes in the orthorhombic space group Pbc21 with unit-cell parameters: a= 5.591(6)Å, b=22.019(3)Å, c = 14.742(2) Å, β = 90.0º, Z = 4. The crystal structure has been elucidated by Direct methods and refined to a final R-value of 0.056 for 1535 observed reflections. In the crystal molecules are linked by two N-H...N intermolecular H-bonds forming dimer. Molecules in the unit cell are packed together to form well defined layers.
Keywords: oximes; intermolecular hydrogen bond; crystal structure; direct methods; N-hydroxy-4-phenylbut-3-en-2-imine
The synthesis of pyrazoles and pyrimidines can be achieved from different chalcones using microwave irradiation within 5-8 min. Pyrazole and pyrimidine are nitrogen containing heterocyclic rings which are versatile lead compound for designing potent bioactive agents. The structures of the products were supported by IR, 1H NMR, 13C NMR and mass spectral data. The synthesized compounds showed a good antibacterial and antifungal activity.
Keywords: microwave irradiation; pyrazole; pyrimidines; antimicrobial activity
Materials and environmental chemistry
Nano flat branched tube structure CrO(OH) (340-447 nm) demonstrated very good catalytic bustle in dye hazardous effluent treatment of textile industry. CrO(OH) Nanoparticles(NPs) have been synthesized using hydrothermal treatment of K2Cr2O7 in a mixed aqueous alcohol system. It was observed that solvent composition and the temperature exhibited imperative effects on the configuration of the end products. Conducting tests demonstrated that the single phase nano-branched particles can be synthesized at elevated reaction temperature and higher percent composition of ethanol with water (>50%). The experiment validates catalytic efficiency of the synthesized CrO(OH) NPs as a catalyst in oxidation of the basic dye methylene blue (MB). Further, the impacts of other parameters were also investigated, including catalyst dosage, H2O2 dosage, catalyst circulation, concentration of dye and acidic media. After reaction of 30 minutes, degradation of methylene blue reached over 80% for most catalyst samples. Spectral analysis proposed that the degradation of MB followed by demethylation. It was observed that the catalytic activity was much advanced than that of the commercial potassium dichromate powder. Characterization of nanoparticle prepared was confirmed by EDS, SEM images and FTIR while effectiveness by UV-Visible spectroscopy.
Keywords: Nano tubes; chromium oxide; catalytic activity; degradation; methylene blue
The uniform cobalt phosphate nanoparticles were successfully synthesized by microwave radiation. The effects of microwave irradiation power and reaction time on the treatment process were investigated. The products synthesized were analyzed by field emission scanning electron microscopy, X-ray powder diffraction, Fourier-transform infrared spectroscopy, thermal gravimetric analyses and dynamic light scattering. In this research, the products were cobalt phosphate phase with nanoparticles over the ranges of 60-80 nm. The data revealed that the nearly spherical particle size decreased with increasing irradiation power. The cobalt phosphate nanoparticles were formed after 10 min of microwave irradiation.
Keywords: Cobalt(II) phosphate; nanoparticles; microwave radiation; X-ray diffraction
Natrolite proved to be an effective adsorbent for the adsorptive removal of lead and chromium ions from aqueous solutions. Adsorption parameters such as pH, adsorbent dose, temperature, and contact time were optimized. For the determination of rate of metal adsorption by natrolite from 50 mL (20 mg L-1), the supernatant was analyzed for residual metals after the contact period of 10-120 min. The effect of pH on metal adsorption by natrolite was determined at values pH 2-8 and the effect of different doses of natrolite from 0.1 to 0.6 was determined, as well as to what extent the adsorption data obey Langmuir and Freundlich adsorption isotherms were also investigated. Thermodynamic studies shows the negative values of ΔG0 at all the temperature indicates the spontaneous nature of Pb(II) and Cr(VI) ions on natural mineral natrolite. Natrolite has shown good results ans exhibits that the pH plays an important role in adsorption of metal ions.
Keywords: natrolite; adsorption; isotherm models; wastewater
Biochemistry, molecular biology and biotechnology
The uptake of carbon nanomaterials by plants has shown a very recent field of nano-agriculture. This work investigated about the beneficial effects of functionalized multiwalled carbon nanotubes on wheat, maize, peanut and garlic. Here in, we explore the potential influence of 0- 50 g mL-1, the MWCNTs on these different seeds at different concentration. The effects of MWCNTs on root and shoot growth, biomass, number of leaves were investigated. It was hypothesized that MWCNTs were able to penetrate the seed coat by creating new pores; thereby enhancing water uptake. The results of the combined morphological and physiological analysis indicate that after about 5-10 days exposure under our experimental conditions MWCNTs significantly enhances plant growth and biomass compared to control. The number and size of leaves of the MWCNTs treated plants had shown positive effects in a dose dependent manner. Nanotubes exposed seeds sprouted up to three to four times faster than controlled. TEM images of peanut root shows the presence of carbon nanotubes that could explain the enhanced water delivery. Overall after investigation we conclude that low dose MWCNT have seen to be beneficial, improving water absorption, found to accelerate the process of germination by shortening the germination time and higher biomass production.
Keywords: carbon nanotubes, growth enhancement, MWCNTs
Industrial and engineering chemistry
Corrosion inhibition by surfactant molecules are related to the surfactant’s ability to aggregate at interfaces and in solution. In this article, the adsorption and corrosion inhibition of series of commercial fatty acid surfactants synthesized based on vegetable oils (sunflower, cottonseed, corn and palm oil) onto mild steel is investigated at 50 ºC in CO2-saturated brine. The inhibition efficiencies of the tested compounds showed good inhibition and protection of the carbon steel even at low concentrations. The corrosion inhibition tendency correlated to the chemical structure of the compounds.
Keywords: corrosion inhibition; surfactants; vegetable oils; fatty acids; adsorption; mild steel
Metal structures are easily destroyed under the environmental influence. A new protective material, an anticorrosive primer based on an emulsion resin ED-20 dispersed in water has been developed and tested.
Keywords: emulsion; epoxy resins; corrosion protection; primer