The subtle effects of iron-containing metal surfaces on the reductive carbonylation of RuCl3

Hexaaqua-iron(II) bis-[fac-tribromido-tricarbonyl-ferrate(II)]

In the title compound, [Fe(H₂O)₆][FeBr₃(CO)₃]₂, both Fe atoms have an octa­hedral coordination and the bromide carbonyl complex has a fac-stereochemistry. The [Fe(H₂O)₆]²⁺ octa­hedron has point symmetry and is slightly compressed along one O—Fe—O axis. The [FeBr₃(CO)₃]⁻ anion has point symmetry 1 and mean bond lengths of Fe—Br = 2.455 (5) Å and Fe—C = 1.809 (2) Å. The cation and anion complexes are mutually linked via O—H⋯Br hydrogen bonds with O⋯Br distances of 3.340 (3) to 3.388 (3) Å.

On the operating mode of bimetallic systems for environmental remediation

This letter challenges the concept that Fe(0)/Me(0) bimetallic systems enhance contaminant reduction on Me(0) surfaces. It is shown on a pure thermodynamic perspective that any enhancement of contaminant reduction by Fe(0) in the presence of a second more electropositive elemental metal (Me(0)) is the result of an indirect process resulting from iron corrosion. This demonstration validates the concept that aqueous contaminant removal in the presence of Fe(0) mostly occurs within an in situ generated oxide film on Fe(0).

An alternative synthesis method for [Os(NN)(CO)2X2] complexes (NN = 2,2′-bipyridine, 4,4′-dimethyl-2,2′-bipyridine; X = Cl, Br, I). Electrochemical and photochemical properties and behavior

A novel synthesis method is introduced for the preparation of [Os(NN)(CO)(2)X(2)] complexes (X = Cl, Br, I, and NN = 2,2'-bipyridine (bpy) or 4,4'-dimethyl-2,2'-bipyridine (dmbpy)). In the first step of this two-step synthesis, OsCl(3) is reduced in the presence of a sacrificial metal surface in an alcohol solution. The reduction reaction produces a mixture of trinuclear mixed metal complexes, which after the addition of bpy or dmbpy produce a trans(Cl)-[Os(NN)(CO)(2)Cl(2)] complex with a good 60-70% yield. The halide exchange of [Os(bpy)(CO)(2)Cl(2)] has been performed in a concentrated halidic acid (HI or HBr) solution in an autoclave, producing 30-50% of the corresponding complex. All of the synthesized trans(X)-[Os(bpy)(CO)(2)X(2)] (X = Cl, Br, I) complexes displayed a similar basic electrochemical behavior to that found in the ruthenium analog trans(Cl)-[Ru(bpy)(CO)(2)Cl(2)] studied previously, including the formation of an electroactive polymer [Os(bpy)(CO)(2)](n) during the two-electron electrochemical reduction. The absorption and emission properties of the osmium complexes were also studied. Compared to the ruthenium analogues, these osmium complexes display pronounced photoluminescence properties. The DFT calculations were made in order to determine the HOMO-LUMO gaps and to analyze the contribution of the individual osmium d-orbitals and halogen p-orbitals to the frontier orbitals of the molecules. The electrochemical and photochemical induced substitution reactions of carbonyl with the solvent molecule are also discussed.