Triiron and Triruthenium Carbonyl Clusters Bearing Bridging Long Chain Diphosphine and Capping Chalcogenido Ligands

Treatment of Ru₃(CO)₁₂ with dpphSe₂ (dpph = 1,6-bis(diphenylphosphino)hexane) in refluxing toluene in the presence of Me₃NO afforded two new compounds, Ru₃(CO)₇(-CO)(₃-Se)(-dpph) (1) and Ru₃(CO)₇(₃-Se)₂(-dpph) (2). A similar reaction of Ru₃(CO)₁₂ with dpppeSe₂ (dpppe = 1,5-bis(diphenylphosphino)pentane) gave exclusively Ru₃(CO)₇(₃-Se)₂(-dpppe) (3). Treatment of Ru₃(CO)₁₂ with dpphS₂ and dpppeS₂ at 110°C in the presence of Me₃NO afforded Ru₃(CO)₇(₃-S)₂(-dpph) (4) and Ru₃(CO)₇(₃-S)₂(-dpppe) (5), respectively. Reactions of Fe₃(CO)₁₂ with dpphSe₂ and dpppeSe₂, under identical conditions, afforded Fe₃(CO)₇(₃-Se)₂(-dpph) (6) and Fe₃(CO)₇(₃-Se)₂(-dpppe) (7), respectively. Compounds 1–7 were characterized spectroscopically and the molecular structures of compounds 1–4 were determined by single crystal X-ray crystallography. The core of 1 contains an equilateral triangle of ruthenium atoms with one capping selenium, one bridging dpph, one doubly bridging carbonyl and seven terminal carbonyl ligands. Complexes 2–4 have a square-pyramidal structure with two metal and two chalcogenide atoms alternating in the basal plane and the third metal atom at the apex of the pyramid, and belong to the family of well-known nido clusters with seven skeletal electron pairs.     

Comparison of Fatty Acid Contents and MMP-1 Inhibitory Effects of the Two Antarctic Fish,Notothenia rossii and Champsocephalus gunnari

Total fatty-acid (FA) contents of different organs (stomach, liver, brain, and skin) of two Antarctic fish, marbled rockcod (Notothenia rossii) and mackerel icefish (Champsocephalus gunnari), were examined using gas chromatography–mass spectrometry (GC–MS). N. rossii possessed higher contents of total omega-3, where eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), the most represented omega-3 FAs, were distributed throughout all parts of the fish. The highest level of EPA was observed in the skin and that of DHA was observed in the brain of N. rossii. C. gunnari showed organ peculiarity in that most of the omega-3 FAs were found in stomach and skin. Specifically, the highest levels of EPA and DHA were both observed in the stomach. Although N. rossii and C. gunnari both inhabit the Antarctic Southern Oceans, their characteristics in terms of the composition of fatty acids were shown to vary. The extracts were also evaluated for matrix metalloproteinase-1 (MMP-1)-inhibitory activities in UVB-induced human dermal fibroblasts, where extracts of the skin and liver of N. rossii showed the most significant inhibition upon MMP-1 production. These findings provide experimental evidence that the extracts of the Antarctic fish could be utilized as bioactive nutrients, particularly in the enhancement of skin health.     

Synthesis of linseed oil based biodegradable homo and copolymers: role as multifunctional greener additives in lube oil

Abstract

Homopolymer of linseed oil and its four copolymers with styrene, 1-decene, isodecyl acrylate and octyl acrylate, respectively, have been synthesized in this present context. The prepared polymers are characterized by NMR and FTIR spectroscopy. The molecular weights have been measured by gel permeation chromatography. Their effectiveness as pour point depressant (PPD), viscosity index improver (VII) and their shear stability in terms of permanent shear stability index have been evaluated in lube oil. The copolymers acted as better PPDs than the homopolymer whereas the homopolymer of linseed oil excelled as VII. Further it was observed that all the prepared polymers were stable enough under severe mechanical shear.     

Polyphenolics with Strong Antioxidant Activity from Acacia nilotica Ameliorate Some Biochemical Signs of Arsenic-Induced Neurotoxicity and Oxidative Stress in Mice

Neurotoxicity is a serious health problem of patients chronically exposed to arsenic. There is no specific treatment of this problem. Oxidative stress has been implicated in the pathological process of neurotoxicity. Polyphenolics have proven antioxidant activity, thereby offering protection against oxidative stress. In this study, we have isolated the polyphenolics from Acacia nilotica and investigated its effect against arsenic-induced neurotoxicity and oxidative stress in mice. Acacia nilotica polyphenolics prepared from column chromatography of the crude methanol extract using diaion resin contained a phenolic content of 452.185 ± 7.879 mg gallic acid equivalent/gm of sample and flavonoid content of 200.075 ± 0.755 mg catechin equivalent/gm of sample. The polyphenolics exhibited potent antioxidant activity with respect to free radical scavenging ability, total antioxidant activity and inhibition of lipid peroxidation. Administration of arsenic in mice showed a reduction of acetylcholinesterase activity in the brain which was counteracted by Acacia nilotica polyphenolics. Similarly, elevation of lipid peroxidation and depletion of glutathione in the brain of mice was effectively restored to normal level by Acacia nilotica polyphenolics. Gallic acid methyl ester, catechin and catechin-7-gallate were identified in the polyphenolics as the major active compounds. These results suggest that Acacia nilotica polyphenolics due to its strong antioxidant potential might be effective in the management of arsenic induced neurotoxicity.     

In-vitro drug–drug interaction studies of diltiazem with floroquinolones

Diltiazem is an established cardiovascular drug mainly used for the management of hypertension specifically for the angina pectoris. Fluoroquinolones are widely prescribed against the treatment of severe infections. In vitro relations of diltiazem with fluoroquinolones (ciprofloxacin, levofloxacin, norfloxacin, and ofloxacin) were examined using spectrophotometric and separation techniques, i.e., RP-HPLC. Diltiazem’s availabilities were observed to be predisposed highly in the presence of fluoroquinolones. To investigate the mechanism of interaction in a variety of dissolution environments, i.e., simulating body environments with regard to pH on these interactions has been studied. Moreover, complex of diltiazem–fluoroquinolones were prepared and elucidated through IR spectroscopy and confirmed by computational molecular modeling.     

Silica-Functionalized CuI: An Efficient and Selective Catalyst for N-Benzylation,Allylation, and Alkylation of Primary and Secondary Amines in Water

Silica-functionalized CuI has been reported as an efficient and selective catalyst for the selective mono-N- and N,N-dibenzylation, allylation, and alkylation of primary amines with benzylic, allylic, and alkyl halides using NaOH as base in aqueous medium. By changing the reaction temperature, mono- or di-benzylation, allylation, or alkylation could be achieved in good yield and selectivity. Secondary amines have also been benzylated, allylated, and alkylated under similar conditions. SiO₂-CuI has been characterized by Fourier transform–infrared, atomic absorption spectrometry, thermalgravimetric analysis, X-ray diffraction, scanning electron microscopy, and transmission electron microscopy, and found to be highly selective and recyclable under the reaction conditions.

[Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications® for the following free supplemental resource(s): Full experimental and spectral details.]     

Simultaneous determination of gliquidone, pioglitazone hydrochloride, and verapamil in formulation and human serum by RP-HPLC

In the present study, a reverse-phase high performance liquid chromatography method was developed, validated and applied for the simultaneous determination of gliquidone, pioglitazone hydrochloride and verapamil in tablets and human serum. Chromatographic separation was achieved on a C18 column (5 μm, 25 × 0.46 cm) with a mobile phase consisting of methanol-water-acetonitrile (80:10:10 v/v/v) with a flow rate of 0.7 mL/min and pH adjusted to 3.50 with phosphoric acid at 230 nm. Glibenclamide was used as internal standard. The experimentally derived limit of detection and limit of quantitation were determined to be 0.24, 0.93, 0.40, and 0.80, 3.11, 1.36 μg/mL for gliquidone, pioglitazone, and verapamil, respectively. There were no interfering peaks due to the excipients present in the pharmaceutical tablets. Thus, the proposed method is simple and suitable for the simultaneous analysis of active ingredients in dosage forms and human serum.     

Development and validation of stability-indicating HPLC method for the simultaneous determination of paracetamol, tizanidine, and diclofenac in pharmaceuticals and human serum

A method is described for the simultaneous determination of paracetamol, tizanidine, and diclofenac in mixtures. The method was based on HPLC separation of the three drugs followed by UV detection at 254 nm. The separation was carried out on a Hypersil ODS, C18 (250 x 4.6 mm id, 10 microm particle size) column using the mobile phase aqueous 0.2% ammonium carbonate-methanol (60 + 40, v/v) at a flow rate of 1 mL/min. The linear regression analysis data were used for the regression curve in the range of 170-10 000 ng/mL for paracetamol, 120-10 000 ng/mL for tizanidine, and 20-10 000 ng/mL for diclofenac. No chromatographic interference from tablet excipients was found. In order to check the selectivity of the proposed method, degradation studies were carried out using hydrolysis (acid, basic, and neutral), thermolysis, and oxidation. The developed method, after being validated in terms of precision, robustness, recovery, LOD, and LOQ, was successively applied to the analysis of pharmaceutical formulations and human serum.     

Effects of exponential volume fraction law on the natural frequencies of FGM cylindrical shells under various boundary conditions

In the present work, vibration characteristics of thin functionally graded cylindrical shells are studied under the influence of various boundary conditions. Fabrication of FGM cylindrical shell is carried out by using exponential volume fraction law. Strain- and curvature-displacements relationships are taken from Love’s thin shell theory. The frequency equation in the form of eigenvalue problem is obtained by adapting the Rayleigh-Ritz method. Characteristic beam functions are assumed to approximate the axial modal dependence. Effects of exponential volume fraction law on the natural frequencies of the FGM cylindrical shells for various boundary conditions are studied against circumferential wave number, length to radius ratio and thickness to radius ratio for different values of power law exponents. Results evaluated show good agreement with those available in the literature.