Search results for "COMPOUND"

Fate of organic pollutants after sewage sludge spreading on agricultural soils: a 30-years field-scale recording

2006

Le DOI mentionné dans l'article 10.2166/WPT.2007.008 ne fonctionne pas; International audience; Toxic organic compounds, such as the surfactants linear alkylbenzene sulfonates (LAS) and nonylphenol polyethoxylates (NPE), Polycyclic aromatic hydrocarbons (PAH) and residues derived from plastics (PAE-phthalates) end up in sewage sludge. In order to evaluate and quantify the potential environmental risks associated with the xenobiotic introduction into biological life cycle, the EU BIOWASTE project (QLK5-CT-2002-01138) devotes one task to the study of the fate of xenobiotic in a sandy soil after sludge spreading on a 30-year field-scale record experiment. Experimental maize crop fields from Bo…

Addition of Ethylene or Hydrogen to a Main-Group Metal Cluster under Mild Conditions

2015

Reaction of the tin cluster Sn8(Arinline image)4 (Arinline image=C6H2-2,6-(C6H3-2,4,6-Me3)2) with excess ethylene or dihydrogen at 25 °C/1 atmosphere yielded two new clusters that incorporated ethylene or hydrogen. The reaction with ethylene yielded Sn4(Arinline image)4(C2H2)5 that contained five ethylene moieties bridging four aryl substituted tin atoms and one tin–tin bond. Reaction with H2 produced a cyclic tin species of formula (Sn(H)Arinline image)4, which could also be synthesized by the reaction of {(Arinline image)Sn(μ-Cl)}2 with DIBAL-H. These reactions represent the first instances of direct reactions of isolable main-group clusters with ethylene or hydrogen under mild conditions…

Trapping and Reactivity of a Molecular Aluminium Oxide Ion

2019

Aluminium oxides constitute an important class of inorganic compound that are widely exploited in the chemical industry as catalysts and catalyst supports. Due to the tendency for such systems to aggregate via Al‐O‐Al bridges, the synthesis of well‐defined, soluble, molecular models for these materials is challenging. Here we show that reactions of the potassium aluminyl complex K 2 [( NON )Al] 2 ( NON = 4,5‐bis(2,6‐diiso‐propylanilido)‐2,7‐di‐tert‐butyl‐9,9‐dimethylxanthene) with CO 2 , PhNCO and N 2 O all proceed via a common aluminium oxide intermediate. This highly reactive species can be trapped by coordination of a THF molecule as the anionic oxide complex [( NON )AlO(THF)] ‐ , which …

Low‐Valent Germanylidene Anions: Efficient Single‐Site Nucleophiles for Activation of Small Molecules

2021

Abstract Rare mononuclear and helical chain low‐valent germanylidene anions supported by cyclic (alkyl)(amino)carbene and hypermetallyl ligands were synthesised by stepwise reduction from corresponding germylene precursors via stable and isolable germanium radicals. The electronic structures of the anions can be described with ylidene and ylidone resonance forms with the Ge−C π‐electrons capable of binding even weak electrophiles. The germanylidene anions reacted with CO2 to give μ‐CO2‐κC:κO complexes, a rare coordination mode for low‐valent germanium and inaccessible for the related neutral germylones. These results implicate low‐valent germanylidene anions as efficient single‐site nucleop…

Labile nitrogen, carbon, and phosphorus pools and nitrogen mineralization and immobilization rates at low temperatures in seasonally snow-covered soi…

2006

Surface mineral horizons from four ecosystems sampled in the northwestern Italian Alps were incubated at −3 and +3°C to simulate subnivial and early thaw period temperatures for a seasonally snow-covered area. The soil profiles at these sites represent extreme examples of management, grazed meadow (site M) and extensive grazing beneath larch (site L) or naturally disturbed by avalanche and colonized by alder (site A) and the expected forest climax vegetation beneath fir (site F). Changes in labile pools of nitrogen (N) and phosphorus (P) were active at all sites at both temperatures during 14 days of laboratory incubation. Ammonium was the dominant inorganic form of total dissolved N (TDN),…

Soil carbon in Mediterranean ecosystems and related management problems

2011

Implication of pyoverdines in the interactions of fluorescent pseudomonads with soil microflora and plant in the rhizosphere

2008

International audience

Combined Use of Structure Analysis, Studies of Molecular Association in Solution, and Molecular Modelling to Understand the Different Propensities of…

2021

The arrangement of hydroxyl groups in the benzene ring has a significant effect on the propensity of dihydroxybenzoic acids (diOHBAs) to form different solid phases when crystallized from solution. All six diOHBAs were categorized into distinctive groups according to the solid phases obtained when crystallized from selected solvents. A combined study using crystal structure and molecule electrostatic potential surface analysis, as well as an exploration of molecular association in solution using spectroscopic methods and molecular dynamics simulations were used to determine the possible mechanism of how the location of the phenolic hydroxyl groups affect the diversity of solid phases formed…

Chasing Weak Forces: Hierarchically Assembled Helicates as a Probe for the Evaluation of the Energetics of Weak Interactions.

2017

London dispersion forces are the weakest interactions between molecules. Because of this, their influence on chemical processes is often low, but can definitely not be ignored, and even becomes important in cases of molecules with large contact surfaces. Hierarchically assembled dinuclear titanium(IV) helicates represent a rare example in which the direct observation of London dispersion forces is possible in solution even in the presence of strong cohesive solvent effects. Hereby, the dispersion forces do not unlimitedly support the formation of the dimeric complexes. Although they have some favorable enthalpic contribution to the dimerization of the monomeric complex units, large flexible…

Sonication-Induced Modification of Carbon Nanotubes: Effect on the Rheological and Thermo-Oxidative Behaviour of Polymer-Based Nanocomposites.

2018

The aim of this work is the investigation of the effect of ultrasound treatment on the structural characteristics of carbon nanotubes (CNTs) and the consequent influence that the shortening induced by sonication exerts on the morphology, rheological behaviour and thermo-oxidative resistance of ultra-high molecular weight polyethylene (UHMWPE)-based nanocomposites. First, CNTs have been subjected to sonication for different time intervals and the performed spectroscopic and morphological analyses reveal that a dramatic decrease of the CNT's original length occurs with increased sonication time. The reduction of the initial length of CNTs strongly affects the nanocomposite rheological behavio…