COMPARISON OF THE SOIL RADIOACTIVE AND HEAVY METALS POLLUTION WITH PHYSIOLOGICAL PARAMETERS OF TEST PLANTS AT THE FACILITIES OF SUKHACHEVSKY INDUSTRIAL SITE

The work aimed to assess the impact of Baza S uranium ore storage site and Sukhachevskoye uranium mill tailing impoundment on physiological parameters of test plants

Grafting a homogeneous transition metal catalyst onto a silicon AFM probe: a promising strategy for chemically constructive nanolithography

International audienceWe report a novel approach to chemically selective lithography using an atomic force microscope (AFM) probe with immobilized homogeneous catalyst, potentially giving access to diverse nanoscale transformations of the surface-bound functional groups. This new concept was proven for the local epoxidation of an alkene-terminated self-assembled monolayer on silicon using H2O2 as an oxidant and a catalytic silicon AFM tip charged with manganese complexes with 1,3,7-triazacyclononane type ligands

Soil Contamination Mapping with Hyperspectral Imagery: Pre- Dnieper Chemical Plant (Ukraine) Case Study

Radioactive contamination of soils is an issue of severe importance for Ukraine remaining with a significant post-Soviet baggage of not settled problems regarding radioactive waste. Regular radioecological observations and up-to-date contamination mapping based on advanced geoinformation techniques give an ability to prepare for, respond to, and manage potential adverse effects from pollution with radionuclides and heavy metals. Hyperspectral satellite imagery provides potentially powerful tool for soil contamination detection and mapping. An intention to find a relation between remotely sensed hyperspectral and ground-based measured soil contamination fractions in area of the uranium mill tailings deposits near Kamianske city was made. An advanced algorithm based on known TCMI (target-constrained minimal interference)-matched filter with a nonnegative constraint was applied to determine the soil contamination fractions by hyperspectral imagery. The time series maps of spatial distribution of the soil contamination fractions within study area around the Sukhachevske tailings dump are presented. Time series analysis of the map resulted in two independent parameters: the average value for the entire observation period and the daily mean increment of the soil contamination fractions

Structural and magnetic diversity in alkali-metal Manganate chemistry : evaluating donor and alkali-metal effects in co-complexation processes

By exploring co-complexation reactions between the manganese alkyl Mn(CH2SiMe3)2 and the heavier alkali-metal alkyls M(CH2SiMe3) (M=Na, K) in a benzene/hexane solvent mixture and in some cases adding Lewis donors (bidentate TMEDA, 1,4-dioxane, and 1,4-diazabicyclo[2,2,2] octane (DABCO)) has produced a new family of alkali-metal tris(alkyl) manganates. The influences that the alkali metal and the donor solvent impose on the structures and magnetic properties of these ates have been assessed by a combination of X-ray, SQUID magnetization measurements, and EPR spectroscopy. These studies uncover a diverse structural chemistry ranging from discrete monomers [(TMEDA)2MMn(CH2SiMe3)3] (M=Na, 3; M=K, 4) to dimers [(KMn(CH2SiMe3)3C6H6)2] (2) and [(NaMn(CH2SiMe3)3)2(dioxane)7] (5); and to more complex supramolecular networks [(NaMn(CH2SiMe3)3)∞] (1) and [(Na2Mn2(CH2SiMe3)6(DABCO)2)∞] (7)). Interestingly, the identity of the alkali metal exerts a significant effect in the reactions of 1 and 2 with 1,4-dioxane, as 1 produces coordination adduct 5, while 2 forms heteroleptic [((dioxane)6K2Mn2(CH2SiMe3)4(O(CH2)2OCH=CH2)2)∞] (6) containing two alkoxide-vinyl anions resulting from α-metalation and ring opening of dioxane. Compounds 6 and 7, containing two spin carriers, exhibit antiferromagnetic coupling of their S=5/2 moments with varying intensity depending on the nature of the exchange pathways

Activation and discovery of earth-abundant metal catalysts using sodium tert-butoxide

First-row, earth-abundant metals offer an inexpensive and sustainable alternative to precious-metal catalysts. As such, iron and cobalt catalysts have garnered interest as replacements for alkene and alkyne hydrofunctionalization reactions. However, these have required the use of air- and moisture-sensitive catalysts and reagents, limiting both adoption by the non-expert as well as applicability, particularly in industrial settings. Here, we report a simple method for the use of earth-abundant metal catalysts by general activation with sodium tert-butoxide. Using only robust air- and moisture-stable reagents and pre-catalysts, both known and, significantly, novel catalytic activities have been successfully achieved, covering hydrosilylation, hydroboration, hydrovinylation, hydrogenation and [2π+2π] alkene cycloaddition. This activation method allows for the easy use of earth-abundant metals, including iron, cobalt, nickel and manganese, and represents a generic platform for the discovery and application of non-precious metal catalysis

Dehydrocoupling of dimethylamine-borane promoted by manganese(II) m-terphenyl complexes

Two- and three-coordinate manganese m-terphenyl complexes are precatalysts for the dehydrogenation of dimethylamine-borane (Me2NH·BH3) affording one equivalent of molecular hydrogen and half an equivalent of [Me2N–BH2]2. Experimental studies into the nature of the catalyst indicate that small changes in the coordination environment give rise to significant differences in the reaction mechanism, occurring through a homogeneous mechanism for two-coordinate precatalysts, whilst for the three-coordinate species a heterogeneous mechanism takes place where nanoparticles are responsible for the catalysis

Filling a niche in “ligand space” with bulky, electron-poor phosphorus (III) alkoxides

The chemistry of phosphorus(III) ligands, which are of key importance in coordination chemistry, organometallic chemistry and catalysis, is dominated by relatively electron-rich species. Many of the electron-poor P(III) ligands that are readily available have relatively small steric profiles. As such, there is a significant gap in “ligand space” where more sterically bulky, electron-poor P(III) ligands are needed. This contribution discusses the coordination chemistry, steric and electronic properties of P(III) ligands bearing highly fluorinated alkoxide groups of the general form PRn(ORF)3-n, where R = Ph, RF = C(H)(CF3)2 and C(CF3)3; n = 1-3. These ligands are simple to synthesize and a range of experimental and theoretical methods suggest that their steric and electronic properties can be “tuned” by modification of their substituents, making them excellent candidates for large, electron-poor ligands