Search results for "Spectroscopy"
showing 10 items of 10293 documents
Analysis of emerging contaminants and nanomaterials in plant materials following uptake from soils
2017
The reuse of treated wastewater or wastewater-impacted river water is growing, particularly in arid areas, due to the climate change. As well, the disposal of sludges, biosolids or biochar as soil amendments to improve agricultural output is widely implemented in the EU. These practices can be a source of emerging contaminants and engineering nanomaterials (ENMs) to the environment and condition their incorporation to food chain that could affect human beings. This review covers current analytical techniques, instruments and methodologies used to determine emerging contaminants and ENMs from irrigation water and/or soil amendments in plants. Trends regarding sample treatment, separation and…
Novel bile acid conjugates with aryl/alkenyl linker: Synthesis and characterization
2008
Abstract Eight potential precursors for the design of bile acid derived receptors viz. 2,6-bis[dimethyl(3α-hydroxy-5β-cholan-24-amidoethyl)ammonio-methyl]naphthalene dibromide (1), 3,3′-bis[dimethyl(3α-hydroxy-5β-cholan-24-amidoethyl)ammoniomethyl]biphenyl dibromide (2), 3,3′-bis[dimethyl(3α,7α,12α-trihydroxy-5β-cholan-24-amidoethyl)ammoniomethyl]biphenyl dibromide (3), 4,4′-bis[dimethyl(3α-hydroxy-5β-cholan-24-amidoethyl)ammoniomethyl]stilbene dibromide (4), 4,4′-bis[dimethyl(3α,7α,12α-trihydroxy-5β-cholan-24-amidoethyl)ammoniomethyl]stilbene dibromide (5), allyl-dimethyl(3α,7α,12α-trihydroxy-5β-cholan-24-amidoethyl)ammonium bromide (6), 1,4′-bis[dimethyl(3α-hydroxy-5β-cholan-24-amidoethyl…
Isostructural potassium and thallium salts of sterically crowded triazenes: a structural and computational study.
2008
Because of their similar cationic radii, potassium and thallium(I) compounds are usually regarded as closely related. Homologous molecular species containing either K(+) or Tl(+) are very rare, however. We have synthesized potassium and thallium salts MN3RR' derived from the biphenyl- or terphenyl-substituted triazenes Tph2N3H (1a), Dmp(Mph)N3H (1b), Dmp(Tph)N3H (1c), and (Me4Ter)2N3H (1d) (Dmp=2,6-Mes 2C6H3 with Mes=2,4,6-Me3C6H2; Me4Ter=2,6-(3,5-Me2C6H3)2C6H3; Mph=2-MesC6H4; Tph=2-TripC6H4 with Trip=2,4,6-(i)Pr3C6H2). The potassium complexes 2a- d were obtained in almost quantitative yield from the reaction of 1a- d with potassium metal in n-heptane. Metalation of 1a- d with TlOEt afforde…
Sterically crowded triazenides as novel ancillary ligands in copper chemistry
2011
Abstract We have synthesized copper salts MN3RR′ derived from the biphenyl- or m-terphenyl-substituted triazenes Tph2N3H (1a) and Dmp(Tph)N3H (1b) (Dmp = 2,6-Mes2C6H3 with Mes = 2,4,6-Me3C6H2; Tph = 2-TripC6H4 with Trip = 2,4,6-i-Pr3C6H2). The homoleptic copper triazenide [CuN3Tph2] (2a) was obtained in high yield from the metallation of 1a with mesityl copper in n-heptane, while the complex [CuN3(Dmp)Tph] (2b) was generated by the same method in situ only. Reaction of 2a with triphenylphosphane gave the 2:1 adduct [CuN3Tph2(PPh3)2] (3a), regardless of the used complex/donor ratio, while reaction of 2a or 2b with a stochiometric amount of t-butylisonitrile afforded the 1:1 adducts [Tph2N3Cu…
Ordering the amorphous – Structures in PBD LED materials
2012
Abstract The class of 2,5 disubstituted-1,3,4-oxadiazoles containing a biphenyl unit on one side is intensively used as electron transport materials to enhance the performance of organic light emitting diodes (OLEDs). In contrast to the ongoing research on these materials insights in their structure-property relationships are still incomplete. To overcome the structural tentativeness and ambiguities the crystal structures of 2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole, that of the related compound 2-(4-biphenylyl)-5-phenyl-1,3,4-oxadiazole and of 2-(4-biphenylyl)-5-(2,6-dimethylphenyl)-1,3,4-oxadiazole are determined. A comparison with the results of GAUSSIAN03 calculations and…
Atypical Antipsychotics in the Treatment of Acute Bipolar Depression with Mixed Features: A Systematic Review and Exploratory Meta-Analysis of Placeb…
2016
Evidence supporting the use of second generation antipsychotics (SGAs) in the treatment of acute depression with mixed features (MFs) associated with bipolar disorder (BD) is scarce and equivocal. Therefore, we conducted a systematic review and preliminary meta-analysis investigating SGAs in the treatment of acute BD depression with MFs. Two authors independently searched major electronic databases from 1990 until September 2015 for randomized (placebo-) controlled trials (RCTs) or open-label clinical trials investigating the efficacy of SGAs in the treatment of acute bipolar depression with MFs. A random-effect meta-analysis calculating the standardized mean difference (SMD) between SGA an…
Optical System For Measuring The Spectral Retardance Function In An Extended Range
2016
Optical retarders are key elements for the control of the state of polarization of light, and their wavelength dependance is of great importance in a number of applications. We apply a well-known technique for determinig the spectral retardance by measuring the transmission spectra between crossed or parallel polarizers. But we we develop an optical system to perform this measurement in a wide spectral range covering the visible (VIS) and near infrared (NIR) spectrum in the range from 400 to 1600 nm. As a result we can measure the spectral retardance of different retarders and easily identify the kind of reterder (multiple order, zero-order, achromatic). We show results with tunable liquid-…
Dissipation of post-pulse laser-induced alignment of CO2through collisions with Ar
2015
In this paper, laser-induced field-free alignment of CO2 in mixtures with Ar is investigated under dissipative conditions (up to 15 bars) at room temperature. The degree of alignment is temporally monitored by a polarization spectroscopy technique, where a weak probe pulse measures the transient birefringence resulting from the alignment. The data are analyzed with a quantum mechanical density matrix formalism using properly J-dependent and M-dependent state-to-state transfer rates, which was previously successfully tested on pure CO2 and CO2–He mixtures. The same consistency is obtained between experiments and calculations, in particular the decay times of both the transient revivals and t…
Determination of Phenolic Endocrine Disruptors in Cosmetics by High-Performance Liquid Chromatography Mass Spectrometry
2017
An analytical method for the simultaneous determination of bisphenol A, 4-t-octylphenol, 4-n-octylphenol, and 4-n-nonylphenol in cosmetic samples has been developed. These compounds have toxic effe...
Study of the Curing Process of DGEBA Epoxy Resin Through Structural Investigation
2015
In this work, a multi-scale approach with different analytical methods is applied to study the curing process and the structural properties of a diglycidyl ether of bisphenol A (DGEBA) epoxy resin. This monomer, thermally cured using 4,4′-diaminodiphenilsulfone (DDS) as hardener, is analyzed after 10, 45, 90, and 120 min of reaction time at 180 °C to obtain information on samples with different cross-linking densities. Samples are also characterized after extraction in acetone in order to obtain structural information on the insoluble parts. For this purpose, differential scanning calorimetry (DSC), dynamic mechanical thermal analysis (DMTA), solid-state nuclear magnetic resonance (ss-NMR),…