Synthesis and characterization of some novel cyanonitrosyl complexes of chromium(I) with Mannich bases,aromatic aldehyde oximes and syn-phenyl-2-pyridylketoxime

Some new low-spin hexacoordinated cyanonitrosyl complexes of Cr¹ of the type [Cr(NO)(CN)₂(L)₂(H₂)], where L is an aromatic aldehyde oxime or Mannich base, have been prepared by the interaction or K₃[Cr(NO)(CN)₅]· H₂O with L in aqueous AcOH, and characterized by a range of physico-chemical techniques, I.r. data suggest that all the oxime derivatives and Mannich bases act as monodentate ligands by coordinating through the aromatic nitrogen. TMC 2564     

Optical activity in the biaryl series

The relationship between the CD spectra of the chiral biaryls and their stereochemical configuration, as a function of the dihedral angle between the molecular planes of the aromatic moieties, has been investigated for biphenyl, 1,1′-binaphthyl, 1,1′-bianthryl and 9,9′-bianthryl in the exciton approximation and, for the 1,1′-binaphthyls, in the π-SCF approximation. Both methods provide unambiguous assignments of absolute configuration except for biaryls with a critical dihedral angle of π/2 in those with effective D_data2 chromophoric symmetry, or 100–110° in the case of the 1,1′-binaphthyls.     

Solution-based chemical synthesis of boehmite nanofibers and alumina nanorods

This article reports an easy chemical method of synthesizing boehmite nanofibers by a modified sol-gel process involving aluminum isopropoxide precursor. Nanorods of gamma-alumina have been successfully prepared after dehydration of the viscous sol at 600 degrees C for 4 h in air. The boehmite nanofibers and gamma-alumina nanorods were characterized by X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy for surface chemistry and functional groups, scanning electron microscopy, high-resolution transmission electron microscopy with selected area electron diffraction, and energy-dispersed spectroscopy for morphology and structure identification. The length of the boehmite nanofibers was found to be more than 10 mum with a crystalline lattice structure. The mechanism of formation of the boehmite nanofibers included the preferential growth along the longitudinal axis due to interaction between the solvent molecules and the surface OH- groups of hydrogen bonds. It is also suggested that the boehmite nanofibers may have formed due to the inherent instability of the planar structure of the boehmite lattice. The diameter of the gamma-alumina nanorods was found to be less than 10 nm with a varying length in the range of 50-200 nm. Boehmite to gamma-Al2O3 transformation was attributed to the loss of water molecules by internal condensation of protons and hydroxyl ions.     

Metabolic profile of glyburide in human liver microsomes using LC‐DAD‐Q‐TRAP‐MS/MS

The sulfonylurea urea drug glyburide (glibenclamide) is widely used for the treatment of diabetes milletus and gestational diabetes. In previous studies monohydroxylated metabolites were identified and characterized for glyburide in different species, but the metabolite owing to the loss of cyclohexyl ring was identified only in mouse. Glyburide upon incubation with hepatic microsomes resulted in 10 metabolites for human. The current study identifies new metabolites of glyburide along with the hydroxylated metabolites that were reported earlier. The newly identified drug metabolites are dihydroxylated metabolites, a metabolite owing to the loss of cyclohexyl ring and one owing to hydroxylation with dehydrogenation. Among the 10 identified metabolites, there were six monohydroxylated metabolites, one dihydroxylated metabolite, two metabolites owing to hydroxylation and dehydrogenation, and one metabolite owing to the loss of cyclohexyl ring. New metabolites of glyburide were identified and characterized using liquid chromatography–diode array detector–quadruple‐ion trap–mass spectrometry/mass spectrometry (LC‐DAD‐Q‐TRAP‐MS/MS). An enhanced mass scan–enhanced product ion scan with information‐dependent acquisition mode in a Q‐TRAP‐MS/MS system was used to characterize the metabolites. Liquid chromatography with diode array detection was used as a complimentary technique to confirm and identify the metabolites. Metabolites formed in higher amounts were detected in both diode array detection and mass spectrometry detection. Copyright © 2012 John Wiley & Sons, Ltd.     

“Dial-In” Emission from a Unique Flexible Material with Polarization Tuneable Spectral Intensity

The development of organic photoluminescent materials, which show promising roles as catalysts, sensors, organic light-emitting diodes, logic gates, etc., is a major demand and challenge for the global scientific community. In this context, a photoclick polymerization method is adopted for the growth of a unique photoluminescent three-dimensional (3D) polymer film, E, as a model system that shows emission tunability over the range 350–650 nm against the excitation range 295–425 nm. The DFT analysis of energy calculations and π-stacking supports the spectroscopic observations for the material exhibiting a broad range of emission owing to newly formed chromophoric units within the film. Full polarization spectroscopic Mueller matrix studies were employed to extract and quantify the molecular orientational order of both the ground (excitation) and excited (emission) state anisotropies through a set of newly defined parameters, namely the fluorescence diattenuation and fluorescence polarizance. The information contained in the recorded fluorescence Mueller matrix of the organic polymer material provided a useful way to control the spectral intensity of emission by using pre- and post-selection of polarization states. The observation was based on the assumption that the longer lifetime of the excited dipolar orientation is attributed to the compactness of the film.     

Regioselective synthesis of pyrano[3,2-f]quinoline and phenanthroline derivatives using molecular iodine

A series of polysubstituted pyrano[3,2-f]quinoline and phenanthroline derivatives have been synthesized by molecular iodine-catalyzed tandem reaction of various propargylic alcohols with or without substituted amines in excellent yields. Moreover, the cyclized side products are also pyrano[3,2-f]quinoline and phenanthroline derivatives.     

Chemical Composition and Antioxidant Activity of the Leaf Essential Oil of Schefflera venulosa

Chemistry of Natural Compounds -     

Three Bis‐BODIPY Analogous Diruthenium Redox Series: Characterization and Electronic Structure Analysis

The dianion derived from (2Z,6Z)‐3,7‐diphenyl‐N2,N6‐di(pyridin‐2‐yl)pyrrolo[2,3‐f]indole‐2,6(1H,5H)‐diimine (H₂BL), a modified BODIPY ligand precursor, is shown to be capable of bridging two metal complex fragments RuL₂, L=2,4‐pentanedionato (acac^?), 2,2’‐bipyridine (bpy) or 2‐phenylazopyridine (pap) in [Ru(acac)₂Ru(μ‐BL)Ru(acac)₂] ( 1 / 2 ), [Ru(bpy)₂Ru(μ‐BL)Ru(bpy)₂](ClO₄)₂ ([ 3 ](ClO₄)₂) and [Ru(pap)₂Ru(μ‐BL)Ru(pap)₂](ClO₄)₂ ([ 4 ](ClO₄)₂). The compounds, including a diastereoisomeric pair 1 (meso) and 2 (rac) were spectroscopically and structurally characterized. Reversible electron transfers as revealed by cyclic and differential pulse voltammetry allowed for an EPR and UV‐vis‐NIR spectroelectrochemical investigation of several neighboring charge states. Together with susceptibility measurements and TD‐DFT calculations the assignment of oxidation states reveals that 1 , 2 are diruthenium(III) species which can be oxidized or reduced by one electron whereas 3 ²⁺ and 4 ²⁺ contain ruthenium(II) and get reduced or oxidized mainly at the dianionic bridge ( 3 ²⁺) or are reduced at the ancillary ligands pap ( 4 ²⁺).