Search results for "compounds"
showing 10 items of 3372 documents
Hexanuclear copper(ii) cage with {Cu3O⋯H⋯OCu3} core supported by a dicompartmental oxime ligand with m-xylyl spacer: synthesis, molecular structure a…
2010
A new dicompartmental dioxime ligand (H(2)L) with m-xylyl spacer between the donor sites has been synthesised by Schiff-base condensation of α,α'-diamino-m-xylene and diacetyl monooxime. The ligand reacts with copper(ii) salts giving rise to hexanuclear tricationic copper(II) cage complexes [Cu(II)(6)(μ(3)-O···H···O-μ(3))L(3)(H(2)O)(6)]X(3) (X = BF(4), 1a; X = ClO(4), 1b). The complexes have been characterised by different analytical and spectroscopic techniques and confirmed the hexanuclear structure even in solution. Single crystal X-ray diffraction studies of both the complexes revealed a very similar core structure with three dicompartmental ligands supporting two triangular Cu(3)O core…
A Gadolinium(III) Complex Based on the Thymine Nucleobase with Properties Suitable for Magnetic Resonance Imaging
2021
The paramagnetic gadolinium(III) ion is used as contrast agent in magnetic resonance (MR) imaging to improve the lesion detection and characterization. It generates a signal by changing the relaxivity of protons from associated water molecules and creates a clearer physical distinction between the molecule and the surrounding tissues. New gadolinium-based contrast agents displaying larger relaxivity values and specifically targeted might provide higher resolution and better functional images. We have synthesized the gadolinium(III) complex of formula [Gd(thy)2(H2O)6](ClO4)3·2H2O (1) [thy = 5-methyl-1H-pyrimidine-2,4-dione or thymine], which is the first reported compound based on gadolinium…
Substituent effects in nitro derivatives of carbazoles investigated by comparison of low-temperature crystallographic studies with density functional…
2014
The crystal structure of 9H-carbazole, C12H9N, (I), has been redetermined at low temperature for use as a reference structure in a comparative study with the structures of 1-nitro-9H-carbazole, C12H8N2O2, (II), and 9-nitrocarbazole, C12H8N2O2, (III). The molecule of (I) has crystallographically imposed mirror symmetry (Z′ = 0.5). All three solid-state structures are slightly nonplanar, the dihedral angles between the planes of the arene and pyrrole rings ranging from 0.40 (7)° in (III) to 1.82 (18)° in (II). Nevertheless, a density functional theory (DFT) study predicts completely planar conformations for the isolated molecules. To estimate the influence of nitro-group substitution on aroma…
Preparation of potentially porous, chiral organometallic materials through spontaneous resolution of pincer palladium conformers.
2013
Understanding the mechanism by which advanced materials assemble is essential for the design of new materials with desired properties. Here, we report a method to form chiral, potentially porous materials through spontaneous resolution of conformers of a PCP pincer palladium complex ({2,6-bis[(di-t-butylphosphino)methyl]phenyl}palladium(II)halide). The crystallisation is controlled by weak hydrogen bonding giving rise to chiral qtz-nets and channel structures, as shown by 16 such crystal structures for X = Cl and Br with various solvents like pentane and bromobutane. The fourth ligand (in addition to the pincer ligand) on palladium plays a crucial role; the chloride and the bromide primaril…
Environment and Endometriosis: A toxic relationship
2015
Endometriosis is a common, be- nign, estrogen-dependent gynecological dis- ease that represents one of the main causes of hospitalization in industrialized countries. It is well established that a large amount of natural and man-made chemicals are present in the en- vironment and both humans and animals are exposed to them. Dioxin and dioxin-like com- pounds have long biological half-life, can accu- mulate within the organism and could negative- ly affect several physiological processes. The purpose of this review is to provide an overview of the possible relationship between these chemicals and the pathogenesis of en- dometriosis.
Salinity affects nitrate removal and microbial composition of denitrifying woodchip bioreactors treating recirculating aquaculture system effluents
2019
Abstract This study investigated the effect of salinity on microbial composition and denitrification capacity of woodchip bioreactors treating recirculating aquaculture system (RAS) effluents. Twelve laboratory-scale woodchip bioreactors were run in triplicates at 0, 15, 25, and 35 ppt salinities, and water chemistry was monitored every third day during the first 39 days of operation. Microbial communities of the woodchips bioreactors were analyzed at the start, after one week, and at the end of the trial. Woodchip bioreactors removed nitrate at all salinities tested. The highest NO3-N removal rate of 22.0 ± 6.9 g NO3-N/m3/d was obtained at 0 ppt, while 15.3 ± 4.9, 12.5 ± 5.4 and 11.8 ± 4.0…
Salinity affects nitrate removal and microbial composition of denitrifying woodchip bioreactors treating recirculating aquaculture system effluents
2019
This study investigated the effect of salinity on microbial composition and denitrification capacity of woodchip bioreactors treating recirculating aquaculture system (RAS) effluents. Twelve laboratory-scale woodchip bioreactors were run in triplicates at 0, 15, 25, and 35 ppt salinities, and water chemistry was monitored every third day during the first 39 days of operation. Microbial communities of the woodchips bioreactors were analyzed at the start, after one week, and at the end of the trial. Woodchip bioreactors removed nitrate at all salinities tested. The highest NO3-N removal rate of 22.0 ± 6.9 g NO3-N/m3/d was obtained at 0 ppt, while 15.3 ± 4.9, 12.5 ± 5.4 and 11.8 ± 4.0 g NO3-N/…
Topical anti-inflammatory potential of quercetin in lipid-based nanosystems: In vivo and in vitro evaluation
2013
Purpose: To develop quercetin-loaded phospholipid vesicles, namely liposomes and PEVs (Penetration Enhancer-containing Vesicles), and to investigate their efficacy on TPA-induced skin inflammation. Methods: Vesicles were made from a mixture of phospholipids, quercetin and polyethylene glycol 400 (PEG), specifically added to increase drug solubility and penetration through the skin. Vesicle morphology and self-assembly were probed by Cryo-Transmission Electron Microscopy and Small/Wide Angle X-ray Scattering, as well as the main physico-chemical features by Light Scattering. The anti-inflammatory efficacy of quercetin nanovesicles was assessed in vivo on TPA-treated mice dorsal skin by the d…
Unusual Regioselectivity in the Opening of Epoxides by Carboxylic Acid Enediolates
2008
Addition of carboxylic acid dianions appears to be a potential alternative to the use of aluminium enolates for nucleophilic ring opening of epoxides. These conditions require the use of a sub-stoichiometric amount of amine (10% mol) for dianion generation and the previous activation of the epoxide with LiCl. Yields are good, with high regioselectivity, but the use of styrene oxide led, unexpectedly, to a mixture resulting from the attack on both the primary and secondary carbon atoms. Generally, a low diastereoselectivity is seen on attack at the primary center, however only one diastereoisomer was obtained from attack to the secondary carbon of the styrene oxide.
Direct Measurement of Mammographic X-Ray Spectra with a Digital CdTe Detection System
2012
In this work we present a detection system, based on a CdTe detector and an innovative digital pulse processing (DPP) system, for high-rate X-ray spectroscopy in mammography (1–30 keV). The DPP system performs a height and shape analysis of the detector pulses, sampled and digitized by a 14-bit, 100 MHz ADC. We show the results of the characterization of the detection system both at low and high photon counting rates by using monoenergetic X-ray sources and a nonclinical X-ray tube. The detection system exhibits excellent performance up to 830 kcps with an energy resolution of 4.5% FWHM at 22.1 keV. Direct measurements of clinical molybdenum X-ray spectra were carried out by using a pinhole…