Search results for "N compounds"
showing 10 items of 203 documents
An in vitro comparative assessment with a series of new triphenyltin(IV) 2-/4-[(E)-2-(aryl)-1-diazenyl]benzoates endowed with anticancer activities: …
2012
Four new triphenyltin(IV) complexes of composition Ph 3SnLH (where LH = 2-/4-[(E)-2-(aryl)-1-diazenyl]benzoate) (1-4) were synthesized and characterized by spectroscopic ( 1H, 13C and 119Sn NMR, IR, 119Sn Mössbauer) techniques in combination with elemental analysis. The 119Sn NMR spectroscopic data indicate a tetrahedral coordination geometry in non-coordinating solvents. The crystal structures of three complexes, Ph 3SnL 1H (1), Ph 3SnL 3H (3), Ph 3SnL 4H (4), were determined. All display an essentially tetrahedral geometry with angles ranging from 93.50(8) to 124.5(2)°; 119Sn Mössbauer spectral data support this assignment. The cytotoxicity studies were performed with complexes 1-4, along…
Insertion reaction of carbon dioxide into Sn-OR bond. Synthesis, structure and DFT calculations of di- and tetranuclear isopropylcarbonato tin(IV) co…
2006
The reaction of carbon dioxide with the stannane nBu2Sn(OiPr)2 and distannoxane [nBu2(iPrO)Sn]2O leads to the selective insertion into one Sn-OiPr bond generating the corresponding nBu2Sn(OiPr)(OCO2(i)Pr) and nBu2(iPrO)SnOSn(OCO2(i)Pr)nBu2 species. Both compounds are characterised by multinuclear NMR, FT-IR and single-crystal X-ray crystallography. In the solid state, they adopt a dimeric arrangement with bridging isopropoxy and terminal isopropylcarbonato ligands. The X-ray crystal structure of the dinuclear stannane shows that the Sn2O2 ring and the two Sn-OCO2C fragments are nearby coplanar. The same holds for the ladder-type tetranuclear distannoxane. The dimeric structures are also evi…
Effect of tin and lead chlorotriphenyl analogues on selected living cells.
2010
Three kinds of living cells, human embryonic kidney cells, Saccharomyces cerevisiae, and Escherichia coli, were tested for their sensitivity to chlorotriphenyltin and chlorotriphenyllead. The tin compound proved definitely more toxic than the lead derivative, particularly in the case of the human embryonic kidney cells devoid of any protective cell wall. Electron paramagnetic resonance (EPR) comparative studies carried out by using a natural model liposome system (egg yolk lecithin) confirmed considerable changes within the lipid bilayer upon doping by the aforementioned additives, which may be crucial to the mechanism of the observed cell cleavage. The individual dopants revealed diverse i…
Hierarchical Assembly of TiO2 Nanoparticles on WS2 Nanotubes Achieved Through Multifunctional Polymeric Ligands
2007
Thefunctionalization of nanotubes is required in order to bene-fit from their outstanding properties, as any application inmaterials and devices is hindered by processing and manipu-lation difficulties. Only the attachment of appropriate chem-ical functionalities on the nanotube surface allows tailoringof the properties for the respective applications. As an ex-ample, the enhancement of the nanotube solubility is onemajor task since most pristine nanotubes are insoluble inboth water and organic solvents. Thus, the improvement ofthe solubility by chemical functionalization is an importantconcept for synthetic chemists and materials scientists. Tai-loring of the surface chemical bonds might a…
Drug delivery devices based on mesoporous silicate.
2004
A mesoporous material based on aluminosilicate mixture was studied to investigate its ability to include drugs and then release them. Nonsteroidal anti-inflammatory agents such as diflunisal, naproxen, ibuprofen and its sodium salt have been used in this study. The preparation of the mesoporous material and its characterization by X-ray, N2 absorption-desorption isotherm, and thermogravimetry analysis have been described. Drug loading was performed by a soaking procedure. Drug-loaded matrices were characterized for entrapped drug amount, water absorption ability, and thermogravimetric behavior. Drug release studies also were performed at pH 1.1 and 6.8 mimicking gastrointestinal fluids. Exp…
Restricting Magnetic Interaction Pathways in Polyoxometalate Salts of Cationic Nitronyl Nitroxide Free Radicals
2004
Abstract : Salts 1 and 2 that combine the [W 6 O 19 ] 2- Lindqvist anion with the cationic nitronyl nitroxide (NN) free radicals p -MepyNN + and n Bu 3 NCH 2 NN + , respectively, have been synthesized and their structural and magnetic properties have been studied. Keywords: Nitroxide radicals, polyoxometalates, magnetism. Introduction Ferromagnetism based on purely organic materials has raised a lot of interest during the last decade [1]. Most of the studies have been performed with nitronyl nitroxide (NN) radicals due to their persistence, stability and ease of functionalization [2]. Bulk ferromagnetism in these compounds arises from ferromagnetic interactions between open-shell molecules …
Impact of Electrical Stress and Neutron Irradiation on Reliability of Silicon Carbide Power MOSFET
2020
International audience; The combined effects of electrical stress and neutron irradiation of the last generation of commercial discrete silicon carbide power MOSFETs are studied. The single-event burnout (SEB) sensitivity during neutron irradiation is analyzed for unstressed and electrically stressed devices. For surviving devices, a comprehensive study of the breakdown voltage degradation is performed by coupling the electrical stress and irradiation effects. In addition, mutual influences between electrical stress and radiative constraints are investigated through TCAD modeling.
Deep MRD profiling defines outcome and unveils different modes of treatment resistance in standard- and high-risk myeloma
2021
PETHEMA/GEM Cooperative Group.
Excited-state absorption in erbium-doped silica fiber with simultaneous excitation at 977 and 1531 nm
2009
We report a study of the excited-state absorption (ESA) in erbium-doped silica fiber (EDF) pumped at 977 nm, when the fiber is simultaneously excited by signal radiation at 1531 nm. We show, both experimentally and theoretically, that ESA efficiency at 977 nm gets strongly enhanced only in the presence of signal power. Experimentally, this conclusion is supported through the detection of upconversion emission, a “fingerprint” of the ESA process, and through the measurements of the EDF nonlinear transmission coefficient for the pump wavelength, which is sensitive to the ESA value. It is shown that the experimental data are precisely modeled with an advanced five-level Er3+ model developed fo…
Oxygen permeability of hydrogel contact lenses with organosilicon moieties
2002
Oxygen transport through two extended wear (day and night) hydrogel contact lenses that contain organosilicon moieties (balafilcon A and lotrafilcon A) was studied in the hydrate (hydrogel) and dry (xerogel) states. The water uptake increased the oxygen permeability [(Dk)app] and transmissibility [Dk/L(av)] coefficients of the dry materials by about 70%. The (Dk)app for the hydrated lenses was determined following the so-called stack procedure. The values obtained were 107 +/- 4 barrer for balafilcon A and 141 +/- 5 barrer for lotrafilcon A, about 5-10 times larger than those previously reported for conventional (without organosilicon moieties) extended wear hydrogels contact lenses. The Dk…