Understanding ketone hydrogenation catalysis with anionic iridium(iii) complexes: the crucial role of counterion and solvation.

Catalytic asymmetric hydrogenation of ketones is an important approach to prepare valuable chiral alcohols. Understanding how transition metals promote these reactions is key to the rational design of more active, selective and sustainable catalysts. A highly unusual mechanism for asymmetric hydrogenation of acetophenone catalysed by an anionic Ir hydride system, including a strong counterion dependence on catalyst activity, is explored and rationalised here.

New Protocol for the Synthesis of S-Thioesters from Benzylic, Allylic and Tertiary Alcohols with Thioacetic Acid.

A new one-pot solvent-less reaction to convert benzylic, allylic, ferrocenyl or tertiary alcohols into S-thioesters, bench-stable and less odorous precursors of the corresponding thiols, which is based on reactions in neat thioacetic acid in the presence of tetrafluoroboric acid, is presented. Reaction monitoring by NMR and GC of the benzyl alcohol conversion indicated the intermediate formation of benzyl acetate and benzyl thionoacetate (PhCH OC(S)CH ) prior to the slower conversion to the final S-benzyl thioacetate product. Increasing the HBF concentration enhanced the reaction rate, giving good to excellent yield (up to 99 %) for a large scope of alcohols.

Acetate ion addition to and exchange in (1,5-cyclooctadiene)rhodium(I) acetate: relevance for the coagulation of carboxylic acid-functionalized shells of core-crosslinked micelle latexes.

The solution behavior of complex [Rh(COD)(μ-OAc)] in the absence and presence of PPNOAc in dichloromethane has been investigated in detail by multinuclear NMR spectroscopy. Without additional acetate ions, the compound shows dynamic behavior at room temperature, consistent with an inversion of its structure. Addition of PPNOAc reveals an equilibrated generation of [Rh(COD)(OAc)].

Acetate exchange mechanism on a Zr oxo hydroxo cluster: relevance for reshaping Zr-carboxylate coordination adaptable networks.

The kinetics and mechanism of the acetate ligand exchange with free acetic acid in [ZrO(OH)(OCCH)], used as a molecular model of crosslink migration in [ZrO(OH)(carboxylate)(OH)]-based coordination adaptable networks with vitrimer-like properties, has been thoroughly investigated by dynamic H NMR and DFT calculations. The compound maintains its -symmetric Zr structure in CDCl and CD, while it splits into its Zr subunits in CDOD and DO. In the Zr structure, the topologically different acetates (3 chelating, 6 belt-bridging, 2 intercluster-bridging and 1 inner-face-bridging) of the Zr subunits behave differently in the presence of free CHCOOH: very fast exchange for the chelating (coalesced resonance at room temperature), slower exchange for the belt-bridging (line broadening upon warming), no observable exchange up to 65 °C (by EXSY NMR) for the intercluster- and inner-face-bridging.

Ir(η-diene) precatalyst activation by strong bases: formation of an anionic Ir tetrahydride.

The reaction between [IrCl(COD)] and dppe in a 1 : 2 ratio was investigated in detail under three different conditions. [IrCl(COD)(dppe)], 1, is formed at room temperature in the absence of base. In the presence of a strong base at room temperature, hydride complexes that retain the carbocyclic ligand in the coordination sphere are generated.