Nickel tetrazolato complexes synthesized by microwave irradiation: Catecholase like activity and interaction with biomolecules

1,3-Dipolar cycloaddition between nickel-ligated azide in [NiL(N₃)] [HL = 3-(2-diethylamino-ethylimino)-1-phenyl-butan-1-one] and two different organonitriles furnished two new square-planar complexes viz. [NiL(5-phenyltetrazolato)] and [NiL{5-(4-pyridyl)-tetrazolato}]. Both the complexes have been characterized by spectroscopic tools and single-crystal X-ray crystallography. Interaction with different biomolecules revealed that both complexes bind strongly to serum albumin proteins and show moderate catecholase-like activity by catalyzing the oxidation of 3,5-ditertbutylcatechol (3,5-DTBC). Identification of intermediates formed in catechol oxidation has been explored by ESI-MS spectrometry.     

CdS quantum dots for measurement of the size-dependent optical properties of thiol capping

Abstract  

The optical- and size-dependent properties of CdS quantum dots (QDs) were analyzed in the presence and absence of different capping agents in aqueous medium. The QDs have been characterized by UV–Vis, Photoluminescence, Fourier-transform infrared spectroscopy, X-ray diffraction, and Fluorescence lifetime measurements. QDs with the presence of thiol group in cubic phase with small grain size were observed in XRD and decrease in particle size of the same with increase in band gap is deduced through UV–Vis and XRD studies. The FT-IR spectrum confirms the interaction of thiol group with CdS. Fluorescence lifetime of capped QDs was higher compared to uncapped CdS QDs. The surface passivation of thiol group on CdS is shown in photoluminescence studies.     

Understanding the photo-electrochemistry of metal-free di and tri substituted thiophene-based organic dyes in dye-sensitized solar cells using DFT/TD-DFT studies

Ionics - In this work, two 2, 5-disubstituted and three 2, 3, 5-trisubstituted thiophene-based organic dyes have been investigated using the density functional theory. Although substitution at the...     

Pd(0)-catalyzed intramolecular Heck reaction: A general route for fused oxepine derivatives

A simple and facile approach for the synthesis of various structurally different tricyclic bent oxepine frameworks from a readily accessible precursor has been introduced. The synthesis of substituted oxepine derivative involved Pd(0)-catalyzed Heck reaction. This methodology enriches the literature for the large ring formation.     

Extraction,Partial Characterization,and Studies of Some Spectroscopic Properties of the Anionic Polysaccharide from Colocasia Antiquorum

Abstract

The natural anionic polysaccharide (Ps-A) isolated from arum (Colocasia antiquorum) tubers contains 56% neutral sugars as galactose, mannose, rhamnose, and arabinose, and 40% anionic components as galacturonic acid and mannuronic acid. The equivalent weight of Ps-A estimated by conductometric and spectrophotometric titrations is rather high, 1510 ± 5, which on saponification is reduced to 479. This indicates that about two-thirds of the carboxylic groups of Ps-A exist in the esterified form. Ps-A and its saponified product (Ps-B) induce strong metachromasia in the dyes 1,9-dimethyl methylene blue and pinacyanol chloride (PCYN). Ps-A, with its lower charge density, induces relatively sharp and single banded metachrotnatic spectra, but the spectra induced by Ps-B, with its higher charge density, is broad and multiple banded. Ps-A induces weak dichroism in PCYN, indicating a bit of helical asymmetry in its conformation; Ps-B does not induce dichroism in this dye. The failure of Ps-B to induce dichroism presumably indicates that Ps-B has a nonhelical conformation.     

Liquid chromatography tandem mass spectrometry method for the simultaneous stereoselective determination of venlafaxine and its major metabolite,O‐desmethylvenlafaxine,in human plasma

A sensitive, accurate and highly stereoselective assay for the simultaneous determination of venlafaxine (VEN) and its equipotent metabolite, O‐desmethyl venlafaxine (ODV), in human plasma was developed and validated. Analytes were simultaneously extracted from plasma using solid‐phase extraction and detected by tandem mass spectrometry in positive ion mode with a turbo ion spray interface. Deuterium‐labeled VEN and ODV were used as internal standards. Chromatographic separation was performed on a Chiral AGP column, using a time programmed gradient flow with a total run time of 16 min. The method has a lower limit of quantitation of 0.60 ng/mL. The assay was linear over a range 0.60–300.00 ng/mL for both the enantiomers of VEN and ODV, respectively, with coefficient of correlation > 0.99. The extraction recoveries were >77.0% on an average for all the four analytes. The analytes were found stable in plasma through three freeze (?15 °C) and thaw cycles and under storage at room temperature for 8 h, and also in mobile phase at 10 °C for 54 h. The method has shown good reproducibility, with intra‐ and inter‐day variation coefficients < 9%, for all the analytes, and has proved to be very reliable for analysis of VEN and its metabolite in clinical study samples. Copyright © 2012 John Wiley & Sons, Ltd.