Environmental assessment of potential toxic elements in the mining district of Mazarrón (SE, Spain).

Mining areas are highly susceptible to environmental contamination due to the accumulation of potentially toxic elements (PTEs), necessitating regular monitoring to assess environmental risks. In this study, soil samples were collected from two depths (0-15 cm and 15-30 cm) at 74 stations, along with deep waste samples (0-12 m) from three adjacent tailings ponds in the Mazarrón mining area, Spain. Soil/waste physicochemical properties and the Cd, Cu, Zn, and Pb concentrations of total, water-soluble, and bioavailable fractions were analyzed.

Activation of CO, Isocyanides, and Alkynes by Frustrated Lewis Pairs Based on Cp*M/N (M = Rh, Ir) Couples.

The complexes [Cp*M(κ,',″-)][SbF] (Cp* = η-CMe; M = Rh, , Ir, ; = pyridinyl-amidine) display M/N transition metal frustrated Lewis pair reactivity toward a range of substrates containing triple bonds. Whereas the rhodium complex reacts with CO yielding compound [Cp*Rh(CO)(κ,-)][SbF] (), which contains a terminal carbonyl and a carbamoyl group, the iridium complex generates compound [Cp*Ir(κ,,'-)][SbF] (), which only features the carbamoyl group. Compounds and react with stoichiometric amounts of the isocyanides CNR (R = Cyclohexyl, -CH(OMe), CHSO(-Tolyl)) to give the corresponding 1,1-insertion complexes [Cp*M(κ,,'-)][SbF] ().

Diverse and Selective Metal-Ligand Cooperative Routes for Activating Non-Functionalized Ketones.

The rhodium and iridium complexes [Cp*M(κ,,-)][SbF] (Cp* = η-CMe; M = Rh, ; Ir, ; = pyridinyl-amidine ligand) exhibit three different cooperative metal-ligand reactivity modes when interacting with nonfunctionalized ketones. With the methyl ketones CHCOR (R = CH, Ph, CF), activation of the ketone methyl C(sp)-H bond yields ketonyl compounds of formula [Cp*M(CHCOR)(κ,-)][SbF]. With the ketones (CF)CO and CFCOPh, the complexes add to the C═O double bond of the ketone.

Reaction force constant as a descriptor of the principle of non-perfect synchronization.

Context: In this study, a small set of 1,3-dipolar cycloaddition reactions that proceed at the same exothermicity is presented. Our main objective was to extend the application of the reaction force constant concept to gain an understanding of the reactivity principles. Inspired by a recent article where we show that the Bell-Evans-Polanyi principle is fulfilled under the condition of an equal degree of (a)synchronicity, here, we demonstrate that the reaction force constant is also a suitable descriptor to quantify the principle of non-perfect synchronization proposed by Bernasconi as a way to understand deviations from the Bell-Evans-Polanyi principle.

Stereocontrol of Metal-Centred Chirality in Rhodium(III) and Ruthenium(II) Complexes with NN'P Ligand.

Rh(III) and Ru(II) complexes, [RhCl(κ-NN'P-L)][SbF] (1) and [RuCl(κ-NN'P-L)] (2), were synthesised using the tetradentate ligand L (L=N,N-bis[(pyridin-2-yl)methyl]-[2-(diphenylphosphino)phenyl]methanamine). In each case only one diastereomer is detected, featuring cis-disposed pyridine groups. The chloride ligand trans to pyridine can be selectively abstracted by AgSbF, with the ruthenium complex (2) reacting more readily at room temperature compared to the rhodium complex (1) which requires elevated temperatures.