Search results for "AH"
showing 10 items of 6917 documents
Organometallic complexes with biological molecules. IX. Diorgano- and triorgano-tin(IV)[meso-tetra (4-sulfonatophenyl)porphinate] derivatives: solid-…
1997
Diorgano- and triorgano-tin(IV) derivatives of meso-tetra(4-sulfonatophenyl)porphine (H4TPPS) with general formula (R2Sn)2TPPS and (R3Sn)4TPPS (TPPS4−=[meso-tetra(4-sulfonatophenyl)porphinate]4−, R=Me, Bu, Ph) have been obtained and their solid-state configuration inferred on the basis of IR and Mossbauer spectroscopy, while solution-phase studies have been carried out by 1H and 13C NMR in DMSO-d6, together with determination of the in vivo cytotoxicity of the new derivatives towards embryonic development of Ciona intestinalis. In particular, octahedral and trigonal-bipyramidal eq-R3Sn polymeric configurations are proposed, in the solid state, respectively for (R2Sn)2TPPS and (R3Sn)4TPPS co…
Synthesis, crystal structure and magnetic properties of the malonato-bridged bimetallic chain [Mn(II)Cu(II)(mal)2(H2O)4]·2H2O
2000
Abstract The first malonato-bridged bimetallic chain of formula [MnCu(mal)2(H2O)4]·2H2O (1) (H2mal=malonic acid) was prepared and its structure determined by X-ray diffraction methods. Each copper atom in 1 is in a square planar environment formed by four malonate-oxygens from two malonate ligands. The manganese atom is six-coordinated with four water molecules and two cis-coordinated malonate-oxygens from two malonate groups building a distorted octahedral surrounding. The malonate group acts simultaneously as bidentate and monodentate ligand towards copper and manganese atoms respectively, leading to a bimetallic chain. Two structurally different carboxylato-bridges exhibiting an anti–syn…
Preparation and structural studies on the tBu2Sn(IV) complexes with aromatic mono- and dicarboxylic acids containing hetero {N} donor atom
2004
Nine complexes of 'Bu2Sn(IV)(2+) were obtained in the solid state with ligands containing -COOH group(s) and aromatic (N) donor atom. The binding sites of the ligands were identified by FT-IR spectroscopic measurements. It was found that in most cases the -COO- groups are co-ordinated in monodentate manner. Nevertheless, in some of our complexes, the -COO- group forms bridges between two central {Sn} atoms resulting in the formation of an oligomeric structure, a motif that is characteristic only to the nicotinate compound. These pieces of information and the rationalisation of the experimental Sn-119 Mossbauer nuclear quadrupole splittings, Delta, - according to the point charge model forma…
Análisis de prensa sobre la eficiencia energética en la edificación: ideas y conceptos sobre sostenibilidad
2015
En esta investigación se parte de la idea de que entre los años (2009-2011) la fuerte crisis económica vivida en nuestro país debilitó el sector de las energías renovables. Entre las diversas bases de datos revisadas para desarrollar esta investigación, se ha seleccionado la hemeroteca de la Revista de Energías Renovables (http://www.energias-renovables.com/articulos-hemeroteca-11-Hemeroteca) durante el periodo que va desde la Cumbre del Cambio Climático de Copenhague (2009) hasta la de Durban (2011), contrastando la situación del sector en los diarios digitales más destacados de España. Por otro lado, contextualizando la Cumbre de Cambio Climático de Copenhague y el desarrollo de la de Dur…
La respuesta del sistema de Naciones Unidas ante la situación de crisis prolongada en Haití
2016
Haití se ha erigido en un factor de inestabilidad regional que ha derivado en su consideración por parte del Consejo de Seguridad de las Naciones Unidas como una amenaza a la paz y a la seguridad internacionales a lo largo de los últimos 25 años. Este artículo pretende analizar la importancia de la actuación internacional llevada a cabo en Haití, así como si la respuesta del sistema de las Naciones Unidas ante las crisis haitianas ha garantizado unas condiciones de paz y estabilidad que han servido de base para importantes avances en otros ámbitos. Haiti has emerged as a factor of regional instability that led to its consideration by the United Nations Security Council as a threat to peace …
'[I]t wasn’t in the picture and is not': Blind Spots and Vanishing Points in Irish Poetical Self-Portraits
2016
International audience; Pictoriality and a propensity for self-examination and self-representation are characteristic of the poetry of Louis MacNeice, Derek Mahon, Seamus Heaney and Paul Muldoon. In many a poem, these four contemporary Irish poets try to capture their own portraits in words and images, through highly visual poems often inspired by paintings. This paper first examines how these poets use images and invest paintings, how verbal and iconic texts interact in their creations and to what extent self-exegesis is made possible and more successful through ekphrasis. With reference to Jacques Derrida’s essay on self-portraiture—Memoirs of the Blind: Self-Portraits and Other Ruins—thi…
Simultaneous quantification of 18 different phytocannabinoids in serum using a highly sensitive liquid chromatography-tandem mass spectrometry (LC-MS…
2021
Abstract The potential therapeutic effects of various phytocannabinoids and the availability of multiple cannabis-based medicines make it desirable to have an analytical method that simultaneously quantifies a wide range of cannabinoids in blood, beyond delta-9-tetrahydrocannabinol and its metabolites. A liquid chromatography tandem mass spectrometry (LC-MS/MS) method for quantification of 18 phytocannabinoids and cannabinoid metabolites in serum was developed and validated. The method enables simultaneous detection of delta-9-tetrahydrocannabinol, cannabidiol, cannabinol, cannabigerol, cannabichromene, cannabicyclol, tetrahydrocannabivarin and cannabidivarin and their acidic precursors tet…
Effect of the shampoo Ultra Clean on drug concentrations in human hair
2000
The influence of the special shampoo Ultra Clean (Zydot Unlimited, Tulsa, Oklahoma) on the results of hair analyses was investigated. Hair samples from persons (n = 14) with a known history of drug abuse were collected at autopsy. The hair samples were divided into separate strands which were analyzed both after washing with Ultra Clean and without treatment. Hair analyses were performed by methanol extraction under sonication, purification by solid phase extraction and GC/MS in SIM mode according to routine procedures for tetrahydrocannabinol (THC), cocaine, amphetamine, methylenedioxyamphetamine (MDA), methylenedioxymethamphetamine (MDMA), methylenedioxyethylamphetamine (MDE), heroin, 6-m…
Selective determination of ammonium in water based on HPLC and chemiluminescence detection
2005
Abstract A selective and sensitive method has been developed for liquid chromatographic determination of ammonium in water samples. The analyte is derivatized with Dansyl Chloride prior to injection into HPLC. Optimal solution derivatization conditions have been established. The dansyl derivative is separated with the aid of a chromatographic column and post-column mixed with peroxyoxalate (TCPO) and H 2 O 2 in order to perform chemiluminescence detection. The detection limit achieved is 8 μg/L and linear response from 0.027 to 0.750 mg/L of ammonium was obtained. Ammonium ion was determined within 2.4 min under optimum chromatographic conditions. The method is fast, and near 10 derivatized…
Analysis of Polycyclic Aromatic Hydrocarbons and Their Oxygen-Containing Derivatives and Metabolites in Soils
2010
Although polycyclic aromatic hydrocarbons (PAHs) have been extensively studied, the knowledge of their oxygen-containing derivatives and metabolites (OPAHs) in soils is limited. We modified and tested an existing analytical protocol involving pressurized liquid extraction of soil followed by fractionation of target compounds into PAHs and OPAHs on a silica gel column and gas chromatography/ mass spectrometry-based separation and quantification. Polycyclic aromatic hydrocarbons and carbonyl-OPAHs were quantified directly after separation on silica gel columns, and hydroxyl/carboxyl-OPAHs were quantified after silylation with N,O-bis(trimethylsilyl)trifluoroacetamide. Recoveries between 78 an…