A Comparative Study of Electrochemical Reduction of Levulinic Acid on Various Electrodes in Organic Solvents.

Studies on the electrochemical hydrogenation (ECH) of levulinic acid (LA) to valeric acid (VA) or γ-valerolactone (GVL) have mainly focused on the electrochemical reduction of LA in acidic aqueous solutions. However, the narrow range of applied potentials has hindered understanding of some mechanistic aspects of LA electrochemical conversion. Earlier, we discovered that employing proton-deficient non-aqueous reaction media provides more comprehensive insights into the mechanism of LA electrochemical reduction.

Trinuclear ReFePt clusters with a μ-phenylvinylidene ligand: synthetic approaches, rearrangement of vinylidene, and redox-induced transformations.

A series of trinuclear μ-vinylidene ReFePt clusters were synthesized by the application of two approaches: (i) reactions of the binuclear RePt μ-vinylidene complexes with Fe(CO); (ii) ligand substitution or exchange reactions at the Pt atom in the synthesized ReFePt clusters. The molecular structures of CpReFePt(μ-CCHPh)(CO)[P(OEt)]L [L = CO; P(OEt)] were determined by an X-ray diffraction study. The obtained compounds were studied by IR and H, C and P NMR spectroscopy.

Manganese-gold-manganese complex with vinylidene and acetylide units.

A series of reactions of Cp(CO)2Mn[double bond, length as m-dash]C[double bond, length as m-dash]CHPh with different gold(i) complexes of [Au-C[triple bond, length as m-dash]C-R]n (R = 4-C5H4N, C6H5) and (tht)AuCl yielded one novel trinuclear MnAuMn cluster. The structure of this cluster can be rationalized as being formed of a vinylidene Mn-Au binuclear and Mn-acetylide fragments, and the binding between those is achieved mainly through the sharing of the electron pair of the single Mn-C σ-bond of an acetylide unit with the gold center.

Catalyzed M-C coupling reactions in the synthesis of σ-(pyridylethynyl)dicarbonylcyclopentadienyliron complexes.

The reactions between terminal ethynylpyridines, (trimethylsilyl)ethynylpyridines and cyclopentadienyliron dicarbonyl iodide were studied under Pd/Cu-catalyzed conditions to develop a synthetic approach to the σ-alkynyl iron complexes Cp(CO)Fe-C[triple bond, length as m-dash]C-R (R = -, -, -pyridyl). Depending on the catalyst and reagents used, the yields of the desired σ-pyridylethynyl complexes varied from 40 to 95%. In some cases the reactions with -ethynylpyridine gave as byproduct the unexpected binuclear FePd μ-pyridylvinylidene complex [Cp(CO)Fe{μ-η(C):η(C)-κ(N)-C[double bond, length as m-dash]C(H)(-CHN)}(μ-CO)PdI].

Crystal structure of μ-carbonyl-1:2κ:-carbonyl-1κ-(1η-cyclo-penta-dien-yl)iodido-2κ-[μ-2-(pyridin-2-yl)ethene-1,1-diyl-1κ:2κ,]ironpalladium(-) benzene monosolvate.

The reaction of Cp(CO)FeI with 2-ethynyl-pyridine under Sonogashira conditions [5% PdCl(PPh), 10% CuI, THF-NEt (2:1)] afforded the title binuclear μ-pyridyl-vinyl-idene FePd complex () as a benzene solvate, [FePd(CH)(CHN)I(CO)]·CH, in a very low yield rather than the expected iron -pyridyl-ethynyl complex Cp(CO)Fe-C≡C-(2-CHN). The Fe and Pd atoms in are bridged by carbonyl and pyridyl-vinyl-idene ligands, the pyridyl N atom being bonded to the palladium atom. The use of equimolar amounts of PdCl increases the yield of to 12%.