Synthesis and physico-chemical studies of some novel mixed-ligand cyanonitrosyl {CrNO}5 complexes of chromium with 2-3-pyrazoline-5-one derivatives

Summary A new series of spin-paired hexa-coordinated mixed-ligand cyanonitrosyl complexes of chromium (having {CrNO}⁵ electron configuration⁽¹⁾) of the type [Cr(NO)(CN)₂(L)₂(H₂O)] (where L=4-methyl-2-pyrazoline-5-one(1), 2,3-dimethyl-1-phenyl-3-pyrazoline-5-one(2) or 4-dimethylamino-2,3-dimethyl-1-phenyl-3-pyrazoline-5-one(3) have been synthesized in the solid state by the interaction of potassium pentacyanonitrosylchromate(I) monohydrate, K₃[Cr(NO)(CN)₅]· H₂O with L in aqueous acetic acid. The products, which have been characterized by elemental analyses, molar conductances, thermogravimetric analyses, magnetic measurements, electron spin resonance and infrared spectral studies, contain low-spin chromium(I). An octahedral structure has been suggested for the complexes.     

High‐performance liquid chromatographic determination of anti‐ hypertensive drugs on dried blood spots using a fluorescence detector – method development and validation

A selective and sensitive high‐performance liquid chromatography method with fluorescence detection for simultaneous determination of irbesartan, losartan and valsartan on dried blood spots (DBS) has been developed and validated. It involves solvent extraction of a punch of DBS followed by reversed‐phase liquid chromatography on a Lichrospher^® 100 RP‐18e column. Fluorescence detection was performed at 259 and 385 nm as excitation and emission wavelengths, respectively. The detection limits of irbesartan, losartan and valsartan were 1.8, 3.6 and 1.8 ng/mL respectively. The mean recoveries of irbesartan, losartan and valsartan were 98.68, 98.42 and 97.81%, respectively. The mean inter‐day and intra‐day precisions of irbesartan, losartan and valsartan were 2.07 and 1.34%, 1.42 and 1.48%, and 3.20 and 2.15% respectively. The proposed method was simple and rapid. Design of experiments was used to evaluate the robustness of the method. Copyright © 2011 John Wiley & Sons, Ltd.     

‘On water’: unprecedented nucleophilic substitution and addition reactions with 1,4-quinones in aqueous suspension

Unique nucleophilic substitution and addition reactions of 1,4-quinones in aqueous suspension with aromatic amines, primary aliphatic amines, amino acid, ester of amino acid, heterocyclic amines, hydrazine, amide, and thioethers are described in absence of catalyst against the traditional synthetic routes of these reactions in non-aqueous medium in presence of catalyst.     

Inclusive and exclusive measurements in the projectile breakup of 7Li

The inclusive and exclusive measurements were carried out for ⁷Li projectile breakup on ²⁷Al target at 48 MeV. In the inclusive data we have observed a broad peak around the beam velocity for alphas and tritons. The exclusive data for alpha-triton coincidences show good agreement with the post-form DWBA theory of breakup reactions.     

InAs/InAsSb Avalanche Photodiode （APD） for applicaions in long-wavelength infrared region

A generic numerical model of a long-wavelength Avalanche Photodiode (APD) based on narrow bandgap semiconductor InAsSb on InAs substrate is reported for the first time. This model has been applied for theoretical characterization of a proposed N InAS/P-InAsSb avalanche photodiode structure for possible application in 2-5 μm wavelength region. The parameters such as gain,excess noise factor and their trade-off with variation of doping concentration and bias voltage have been estimated for the APD taking into account history-dependent theory of avalanche multiplication process. The LWIR APD is expected to find application in optical gas sensor and in future generation of optical communication system.