Study and fabrication of europium picrate triethylene glycol complex

A mononuclear of [Eu(NO3)(Pic)(H2O)2(EO3)](Pic)·(0.73)H2O complex, where EO3=trietraethylene glycol and Pic=picrate anion, shows a red emission when used as an active layer in a single layer of ITO/EO3-Eu-Pic/Al configuration. The crystal structure of the complex consists of [Eu(NO3)(Pic)(H2O)2(EO3)]+ cation and [Pic]- anion. The Eu(III) ion is coordinated to the 10 oxygen atoms from one EO3 ligand, one Pic anion, one nitrate anion, and two water molecules. The complex is crystallized in triclinic with space group P-1. The hybrids in thin films I and II were prepared in the respective order solution concentrations of 15 and 20 mg/mL the emissive center. Comparing the photoluminescence (PL) and electroluminescence (EL) spectra, we can find that all emissions come from the characteristic transitions of the Eu(III) ion. The EL spectra of both thin films showed the occurrence of the most intense red-light emission around at 612 nm. Comparison of organic light-emitting device (OLED) current intensity characteristics as a function of voltage (I-V) show that the thin film I is better than those found for the thin film II. The thickness of the emitting layer is an important factor to control the current-voltage curve. The sharp and intense emission of the complex at low voltage indicates that the complex is a suitable and promising candidate for red-emitting materials.     

Antioxidant, antimicrobial and tyrosinase inhibitory activities of xanthones isolated from Artocarpus obtusus F.M. Jarrett

One of the most promising plants in biological screening test results of thirteen Artocarpus species was Artocarpus obtusus FM Jarrett and detailed phytochemical investigation of powdered dried bark of the plant has led to the isolation and identification of three xanthones; pyranocycloartobiloxanthone A (1), dihydroartoindonesianin C (2) and pyranocycloartobiloxanthone B (3). These compounds were screened for antioxidant, antimicrobial and tyrosinase inhibitory activities. Pyranocycloartobiloxanthone A (1) exhibited a strong free radical scavenger towards DPPH free radicals with IC50 value of 2 μg/mL with prominent discoloration observed in comparison with standard ascorbic acid, α-tocopherol and quercetin, The compound also exhibited antibacterial activity against methicillin resistant Staphylococcus aureus (ATCC3359) and Bacillus subtilis (clinically isolated) with inhibition zone of 20 and 12 mm, respectively. However the other two xanthones were found to be inactive. For the tyrosinase inhibitory activity, again compound (1) displayed strong activity comparable with the standard kojic acid.     

Recent trends in chiral separations on immobilized polysaccharides CSPs

Polysaccharide CSPs are recognized widely in chiral chromatography but the introduction of immobilized phases (Chiralpak IA, Chiralpak IB and Chiralpak IC columns) is a remarkable achievement. The immobilized CSPs can be used with organic, normal and reversed phase modes; even with prohibited solvents too (tetrahydrofuran, chlorofom, dichloromethane, acetone, 1,4-dioxane, ethylacetate, and certain other ethers). Their susceptibilities to work with a wide range of solvents have increased the range of applications including chiral recognition mechanisms. Besides, these are also useful for monitoring the progress of stereo-specific reactions; normally need prohibited solvents. The present review describes the various aspects of commercial available immobilized chiral columns. Attempts have been made to discuss immobilized polysaccharides CSPs, immobilized vs coated CSPs, comparison of immobilized CSPs, method development, optimization, chiral recognition mechanism and applications. The chiral recognition capabilities of commercial columns were in the order of Chiralpak IA > Chiralpak IB > Chiralpak IC columns; but complimentary to each other. Of course, these CSPs are not fully developed and need more advancements and applications. Definitely, the future of immobilized CSPs is quite better. Hopefully, in the coming years they will be the choice of the chromatographers for chiral separations in liquid chromatography.     

Dinuclear gold (I)-di-N-heterocyclic carbene complexes: syntheses,structure, density functional theory calculation and photoluminescence study

The synthesis and characterizations for a series of dinuclear gold (I)-di-NHC complexes, 1–8 through the trans-metalation method of their respective silver (I)-di-NHC complexes, i–viii are reported (where NHC = N-heterocyclic carbene). The successful complexation of a series of unusual non-symmetrical and symmetrical di-NHC ligands, 3,3'-(ethane-1,2-diyl)-1-alkylbenzimidazolium-1'-butylbenzimidazolium (with alkyl = methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, benzyl) with the gold (I) ions are suggested by elemental analysis, Fourier transform-infrared, ¹H- and ¹³C-NMR data. The ¹³C-NMR spectra of 1–8 show a singlet sharp peak in the range of 190.00–192.00 ppm, indicating the presence of a carbene carbon that bonded to the gold (I) ion. From single crystal X-ray diffraction data, the structure of complex 6 with the formula of [di-NHC-Au (I)]₂·2PF₆ is obtained [where NHC = 3,3'-(ethane-1,2-diyl)-1-hexylbenzimidazolium-1'-butylbenzimidazolium]. The photophysical study in solid state of 6 displays an intense photoluminescence with a strong emission maxima, λ_em = 480 nm, upon excitation at 340 nm at room temperature. Interestingly, the emission maximum at 77 K shows a structural character with a strong peak at 410 nm, a medium at 433 nm and a weak at 387 nm, accompanied by a tail band to about 500 nm.     

Validated LC–MS/MS method for quantitation of a selective JAK1 inhibitor,filgotinib in rat plasma,and its application to a pharmacokinetic study in rats

Filgotinib is a selective JAK1 (Janus kinase) inhibitor, filed in Japan for the treatment of rheumatoid arthritis. In this paper, we report a validated liquid chromatography coupled with tandem mass spectrometry for the quantification of filgotinib in rat plasma using tofacitinib as an internal standard (IS) as per the Food and Drug Administration regulatory guidelines. Filgotinib and the IS were extracted from rat plasma using ethyl acetate as an extraction solvent and chromatographed using an isocratic mobile phase (0.2% formic acid:acetonitrile; 20:80, v/v) at a flow rate of 0.9 mL/min on a Gemini C₁₈ column. Filgotinib and the IS were eluted at ~1.31 and 0.89 min, respectively. The MS/MS ion transitions monitored were m/z 426.3 → 291.3 and m/z 313.2 → 149.2 for filgotinib and the IS, respectively. The calibration range was 0.78–1924 ng/mL. No matrix effect and carryover were observed. Intra- and inter-day accuracies and precisions were within the acceptance range. Filgotinib was stable for three freeze–thaw cycles: on bench-top up to 6 h, in an autosampler up to 21 h, and at −80 ° C for 1 month. This novel method has been applied to a pharmacokinetic study in rats.     

Mononuclear High-spin Octahedral Cobalt(II) Complex with Positive Axial Magnetic Anisotropy: Synthesis,Crystal Structure,and DFT Studies

This article outlines the magnetic features of a new six–coordinate high-spin cobalt(II) complex cis-[Co^II(tmphen)₂(NCS)₂] ( 1 ) achieved via the reactions of cobalt(II) thiocyanate with 3,4,7,8-tetramethyl-1,10-phenanthroline. The complex 1 was thoroughly characterized by different analytical and spectroscopic techniques and further confirmed by single X-ray crystal diffraction pattern. Complex 1 is a neutral molecule and adopt highly distorted six-coordinate CoN₆ octahedral coordination sphere surrounded by two thiocyanate N atoms in cis locations and the equatorial plane is occupied by two imine N atoms from the two tmphen ligand while the remaining two imine N atoms reside in the axial positions. Magnetic susceptibility data of complex 1 revealed that the χ_ΜT values decrease significantly to a value of 1.49 cm³ · K · mol^–1 at 2.0 K on decreasing temperatures below 100 K, mainly ascribed to the significant spin–orbit coupling (SOC) of six-coordinate Co^II ions. Furthermore, a field-dependence measurement was performed at 2 K, which shows a positive curvature up to 27 kOe, while it becomes linear up to 2.01 Nμ_B, which authenticated the fact that only the lowest Kramers doublet of ground state is appreciably populated.     

A combined approach of differential scanning calorimetry and hot-stage microscopy with image analysis in the investigation of sulfathiazole polymorphism

A combination of differential scanning calorimetry and hot-stage microscopy with image analysis has been used to investigate the polymorphism of sulfathiazole. The use of light intensity profiles obtained from the HSM images, as an alternative way to present results of the HSM analysis, was found to be useful in describing and verifying thermal events. The approach provides a unique insight into the polymorphic transformations and thermal behaviour exhibited by this compound. The results of the experiments show that sulfathiazole tends to crystallise as mixtures of polymorphs, even though the literature methods for producing pure polymorph were followed.     

Phosphorus ligands for iron(III)‐mediated ATRP of styrene via generation of activators by monomer addition

Styrene polymerization via generation of activators by monomer addition (GAMA) for atom transfer radical polymerization (ATRP) has been examined extensively with bulk FeX₃ and FeX₂ at 110 °C in conjunction with various phosphorus‐bearing ligands. It was found that GAMA possesses advantages over normal ATRP. Most importantly, narrower polydispersity index (PDI) values were observed from the styrene polymerizations with Fe(III) over those with Fe(II). Every instance of 2‐(diphenylphosphino)‐N,N′‐dimethyl‐[1,1′‐biphenyl]‐2‐amine and 2‐(diphenylphosphino) pyridine with the Fe(III) system were controlled excellently without addition of any radical initiator or reducing agent additives. Initiator type was found to exert a significant factor to influence on the controllability of polymerization. The initiation of 1‐phenylethyl chloride and methyl‐2‐chloropropionate gave rise to formation of polymers with narrow PDI (1.05–1.20), whereas those from 1‐phenylethyl bromide increased to 1.35. The GAMA of bulk styrene exhibited the best performance in terms of both rate and controllability compared with toluene and anisole. Both formation of block copolymer from the macroinitiator and efficient perturbation of polymerization with 2,2,6,6‐tetramethylpiperidine 1‐oxyl provided firm evidence to support the living and radical characteristics for the GAMA of styrene. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 144–151, 2010     

An HPTLC Method for the Simultaneous Analysis of Compactin and Citrinin in Penicillium citrinum Fermentation Broth

JPC – Journal of Planar Chromatography – Modern TLC - A simple and precise high-performance thin-layer chromatographic (HPTLC) method has been established for simultaneous analysis of...     

Radiation pasteurised oil palm empty fruit bunch fermented with Pleurotus sajor-caju as feed supplement to ruminants

In solid state fermentation, Pleurotus sajor-caju has been found to be able to degrade at least 30% oil palm empty Fruit Bunch (EFB) fibre leaving 70 % useful materials. Conditions under which fermentation carried out were investigated. It was found that, in the temperature range between 25– 28 °C, relative ph between 6–8, moisture between 60–70 % and medium composition of CaCO₃: rice bran 2 %: 5 % were the optimum conditions. The results showed in fermented products that, there were substantial reduction in cellulosic component such as Crude Fiber (CF, 18 %); Acid Detergent Fibre (ADF, 45 %), Neutral Detergent Fibre (NDF, 61 %) and Acid Detergent Lignin (ADL, 14 %). However, Crude Protein (CP, 10%) increased resulted from single cell protein enrichment of mycelial microbial mass. The mass reductions of substrate in fermentation process corresponds to the CO₂ released during fermentation. Hence, attributable to the decreased in content of CF, ADF, NDF, and ADL. The digestibility study has also been carried out to determine the useful level of this product to ruminant. Aflatoxin content was detected low in both the initial substrates and products. Based on nutritional value and low content of aflatoxin, the product is useful as a source of roughage to ruminant.