Synthesis and spectral studies of novel copper(II) chelates of sulphur-containing oximes

Summary Copper complexes of benzil--monoxime-2-iminoethanethiol (BMETH₂), benzil--monoxime-2-iminobenzenethiol (BMBTH₂), benzil--monoximethiosemicarbazone (BMTH₂) and benzil--monoximesemicarbazone (BMSH₂) were synthesized and characterized by physicochemical and spectroscopic measurements. The molar conductivities show that all of the complexes are nonelectrolytes. The i.r. spectra suggest that the ligands are tetradentate in all cases, whilst the electronic spectra suggest planar geometries for all the complexes. The calculated e.s.r. parameters show an axial dx ² - y ² ground state and suggest coordination through sulphur, in agreement with the i.r. results. In all of these complexes, the =N—;O group acts as a bridging function to give dimeric structures.     

Chemical synthesis and magnetic properties of HCP and FCC nickel nanoparticles

In this study, we successfully synthesized single-phase hexagonal closed packed (HCP) and face-centered cubic (FCC) nickel nanoparticles via reduction of nickel nitrate hexahydrate and nickel acetate tetrahydrate, respectively, in polyethylene glycol-200. Structural information of the as-synthesized nickel nanoparticles are studied by X-ray diffraction (XRD) as a function of the molar concentration of the nickel precursor. XRD results reveal that low concentrations of nickel precursor (0.005?M and below) favor the HCP, while high concentrations favor the mixture of HCP and FCC crystal structures. Particle size of HCP structure is found in the range of ～15?nm via transmission electron microscope analysis. Vibratory sample magnetometer is employed to study its magnetic behavior and the results reveal that FCC crystalline phase shows ferromagnetic nature with high saturation magnetization (M _s?～?39.6?emu?gm^?1) as compared to metastable HCP crystalline structure (M _s?～?2?emu?gm^?1). The surfactants bonding on the surface of nickel nanoparticles are studied.     

Pd‐Mediated Multicomponent Synthesis of Highly Functionalized Pyridines and Consequential C—C Coupling Using Suzuki Reaction in One Pot: Their In Vitro Evaluation as Potential Antibacterial Agents

Pd‐mediated construction of pyridine scaffold and subsequent Suzuki‐based C—C coupling reaction in one pot has been accomplished for the synthesis of 4‐biaryl substituted 2‐amino‐3‐cyanopyridines via multicomponent reaction. The present multicomponent reaction is useful in structural elaboration of pyridine framework and also helpful in design and synthesis of novel and diverse analogs of complex heterocyclic compounds other than present reported molecules. Antibacterial activities of the synthesized compounds were systematically evaluated. The correlation between functional group variation and biological activities of the compounds has been evaluated against human pathogenic gram‐positive and gram‐negative bacterial strains.     

Analytical properties of 2-nitro-5,6-dimethyl-1,3-indanedione dithiosemicarbazone

The synthesis, characterization and analytical properties of 2-nitro-5,6-dimethyl-1,3-indanedione dithiosemicarbazone (NDIDT) are described. NDIDT is used as a chromogenic reagent for the rapid spectrophotometric determination of cobalt(II), palladium(II) and osmium(VIII). The spectrophotometric method developed for cobalt has been used in the analysis of alloys.     

Novel One‐Pot Synthesis of Aziridines Containing Sydnone Moiety

A novel series of 1,1a‐dihydro‐1‐aryl‐2‐(3‐aryl‐sydnone‐4‐yl)‐azirino[1,2‐a] quinoxalines were prepared in a one‐pot reaction of 2,3‐dibromo‐1‐(3‐arylsydnone‐4‐yl‐)‐3‐arylpropan‐1‐one with o‐phenylenediamine employing triethylamine in ethanol. The new compounds were well characterized by IR,¹H NMR, mass spectra, and C,H,N analysis.     

Synthesis of α1-oxindole-α-hydroxyphosphonates under catalyst-free conditions using polyethylene glycol (PEG-400) as an efficient and recyclable reaction medium

A simple, efficient, eco-friendly, and cost-effective method has been developed for the synthesis of α¹-oxindole-α-hydroxyphosphonate derivatives (3a–o) by a one-pot reaction of isatins (1a–o) with trialkyl phosphites (2a–o) under catalyst-free-conditions using inexpensive, non-toxic polyethylene glycol (PEG-400) in excellent yields (82–92%). The present methodology offers an environmental acceptability; low cost, high yields, and recyclability of the PEG-400 are the important features of this protocol.     

Al-doped ZnS layers synthesized by solution growth method

ZnS is one of the potential candidates as a window/buffer layer for solar photovoltaic applications. Al-doped ZnS nanocrystalline films were grown by a simple and economic process, chemical solution growth method. The layers were prepared for different Al-dopant concentrations that vary in the range, 0-10 at. %. The effect of Al-doping on the composition, structure, optical, electrical and photoluminescence properties of the synthesized layers was determined using appropriate techniques. The elemental composition of a typical sample with 6 at. % ‘Al’ in ZnS was Zn = 44.9 at. %, S = 49.8 at. % and Al = 5.3 at. %. The films were nanocrystalline in nature and showed (111) plane of ZnS as the preferred orientation for all the doping concentrations. The layers with 6 at. % of Al showed a crystallite size of ∼9 nm. The FTIR studies confirmed the presence of ZnS in the layers. The layers showed an average transmittance of ∼75% in the visible region. The change of photoluminescence behaviour with dopant concentration was also studied. The electrical resistivity was considerably decreased from 10⁷ Ωcm to 10³ Ωcm with Al-doping. The detailed analysis of results will be presented and discussed.     

Synthesis and Antimicrobial Activity of 2-Methyl-5-nitroaniline Derivatives:A Structure-Activity Relationship Study

A series of 2‐methyl‐5‐nitroaniline derivatives, 5a – 5k and 6a – 6f , were synthesized in order to determine their in vitro antimicrobial activity. The chemical structures of the synthesized compounds were confirmed by elemental analyses, UV‐visible, FT‐IR, ¹H NMR and ¹³C NMR spectral studies. The structure‐activity relationships of the synthesized compounds were also discussed. Among the synthesized compounds, 5f , 5d , 6b and 6e showed good antimicrobial activity compared to standard drugs.