Search results for "Metals"
showing 10 items of 2013 documents
The Influence of Biomass Ash on the Migration of Heavy Metals in the Flooded Soil Profile - Model Experiment
2014
Soils that have been exposed to fl ood waters can be heavily polluted by inorganic and organic compounds. They are mainly compounds which appear in dissolved or suspended form fl owing together with heavily laden fl oodwater, as well as compounds created as a result of reactions in the soil profi le, mostly due to anaerobic transformation of organic matter. Heavy metals brought with fl ood waters are absorbed by the soil and also washed out from fl ood sediments by precipitation when the fl ood recedes. This paper presents the results of research on the effects of fertilization with ash from incineration or pyrolysis of biomass on the migration process of heavy metals (Zn, Cu, Cr, Ni, Pb, C…
Stability of the functional NLO polymers–optically induced depoling of the DMABI molecules in sPMMA matrix
2008
Abstract Low polar order (PO) stability is the major problem of the polymer materials for nonlinear optical (NLO) applications. In this contribution we will show the results of PO stability investigations in the corona poled 3 wt.% DMABI + sPMMA guest–host system. Influence of the poling temperature on the building and stability of the polar order in the system will be presented. To characterize the stability, PO destruction has been caused by high intensity light. Polar order stability characteristics were obtained from the sample second harmonic generation intensity (SHI) time decays. We have found that the decay signal is the best fit to the sum of two exponentials. Several physical mode…
Polymers films with indandione derivatives as alternatives to azobenzene polymers for optical patterning
2008
Surface relief gratings (SRGs) on organic thin films are studied extensively for both scientific interest and in relevance to the applications. Among the chromophores being used the azobenzenes showed the best performance, but the use of alternative photo-sensitive groups provides better general understanding of the phenomena. A thermodynamic theory and molecular dynamics simulations of photoinduced effects are discussed. In this study we use indandione derivatives, known as promising materials for photonics applications, as an alternative to the azobenzenes. We consider their photoreactions when incorporated into a polymer film. One of interesting features is the spectral dependence of the…
Synthesis of chemisorbed imidazolium and phosphonium cations by reaction of ionic liquid precursors with silica.
2010
The reaction of four different basic ionic liquid precursors with Aerosil®300 is presented. Chemisorbed imidazolium and phosphonium cations, with silanolate anions as part of the silicatic support, were obtained and investigated with various solid state NMR techniques.
ChemInform Abstract: Synthesis of Tetrasubstituted 4,4′-Biimidazoles.
2012
Highly substituted 4,4′-biimidazoles were synthesized, in good to excellent yields, through a multicomponent imidazole ring synthesis by using imidazol-4-yl-ethane-1,2-diones as starting materials. The obtained compounds were preliminarily tested as chromogenic and fluorescent sensors for heavy metals.
Recognition and sensing of fluoride anion.
2009
Fluoride anion recognition is attracting a mounting interest in the scientific community due to its duplicitous nature. It is a useful chemical for many industrial applications, and it has been used in human diet, but, recently it has been accused for several human pathologies. Here we describe the ample panorama of different approaches the chemists world-wide have employed to face the challenge of fluoride binding, and we outline some of the research which in our view can contribute to the development of this field, especially when fluoride binding has to be achieved in highly competitive protic solvents and water.
An efficient synthesis of new fluorinated uracil derivativesElectronic supplementary information (ESI) available: general procedures for the preparat…
2003
A series of potentially biologically active fluorinated uracil derivatives has been prepared in three steps from oxazolines and fluorinated nitriles with good chemical yields.
Über Inhibitoren der Korrosion III. Nachweis und Eigenschaften einiger mit Inhibitoren in Salzsäure aufgebauter Schutzschichten auf Eisen
1964
Fur den Aufbau einer Schutzschicht durch den Inhibitor oder eines seiner Folgeprodukte sprechen folgende Befunde: 1 Erhaltung der Schutzwerte nach Ubertragung inhibierter Drahte in inhibitorfreie, frische Salzsaure. 2 Verfolgung des zeitlichen Aufbaus der Schutzschicht durch den gleichen Test. 3 Erhaltung oder Verringerung der Schutzwirkung der inhibierten Drahte (a) durch Behandlung mit verschiedenen Losungsmitteln und (b) durch Bestimmung der thermischen Stabilitat der Schutzschicht. 4 Der an Blei- bzw. Quecksilberkathoden beobachtete Abbau quaternarer Phosphonium- und Arsoniumsalze eroffnet moglicherweise einen Zugang zu den am Aufbau der Schutzschichten beteiligten Verbindungen. On corr…
Uranium( iv ) cyclobutadienyl sandwich compounds: synthesis, structure and chemical bonding
2019
The 1 : 1 reactions of uranium(IV) tetrakis(borohydride) with the sodium and potassium salts of the cyclobutadienyl anion [C4(SiMe3)4]2− (Cb′′′′) produce the half-sandwich complexes [Na(12-crown-4)2][U(η4-Cb′′′′)(BH4)3] and [U(η4-Cb′′′′)(μ-BH4)3{K(THF)2}]2. In the 1 : 2 reaction of U(BH4)4 with Na2Cb′′′′, formation of [U(η4-Cb′′′′)(η3-C4H(SiMe3)3-κ-(CH2SiMe2)(BH4))]− reveals that a Cb′′′′ ligand undergoes an intramolecular deprotonation, resulting in an allyl/tuck-in bonding mode. A computational study reveals that the uranium–Cb′′′′ bonding has an appreciable covalent component with contributions from the uranium 5f and 6d orbitals. peerReviewed
Non-covalent graphene nanobuds from mono- and tripodal binding motifs.
2017
Graphene nanobuds were prepared via the non-covalent anchoring of C60-based molecules endowed with one or three pyrene units, respectively. TGA, FTIR, UV-Vis and TEM investigations confirmed the formation of nanohybrids. For the two molecular derivatives, striking differences were determined in their interaction with graphene or carbon surfaces by Raman, cyclic voltammetry and molecular mechanics calculations, revealing the important role of pyrene adsorption in modulating the electronic properties of the nanohybrids.