For more than three decades the catalytic synthesis of acrylates from the cheap and abundantly available C(1) building block carbon dioxide and alkenes has been an unsolved problem in catalysis research, both in academia and industry. Herein, we describe a homogeneous catalyst based on nickel that permits the catalytic synthesis of the industrially highly relevant acrylate sodium acrylate from CO(2), ethylene, and a base, as demonstrated, at this stage, by a turnover number of greater than 10 with respect to the metal.

The nickel-catalyzed direct carboxylation of alkenes with the cheap and abundantly available C1 building block carbon dioxide (CO2 ) in the presence of a base has been achieved. The one-pot reaction allows for the direct and selective synthesis of a wide range of α,β-unsaturated carboxylates (TON>100, TOF up to 6 h(-1) , TON=turnover number, TOF=turnover frequency). Thus, it is possible, in one step, to synthesize sodium acrylate from ethylene, CO2 , and a sodium salt. Acrylates are industrially important products, the synthesis of which has hitherto required multiple steps.

A new family of monoanionic hemilabile ligands L1H-L3H with a PNN donor set has been developed, based on Pd-catalyzed C-N bond formation and straightforward phosphorylation. For these structurally related compounds with a hybrid set of donor atoms, the coordination chemistry with both Rh and Ir has been studied. The anticipated hemilabile character of the dimethylamino group was assessed by NMR and IR competition experiments, using isopropyl isocyanide as exogenous substrate. Supporting DFT calculations were used to quantify the electronic differences between the various members of the ligand family. In effect, we have constructed a modular ligand class that exhibits tunable hemilability.

Methyl iodide induces the stoichiometric cleavage of nickelalactones, which are key intermediates in the nickelmediated reaction of CO 2 and alkenes to acrylates. Herein, we propose a modified and extended mechanism for this reaction on the basis of theoretical and experimental investigations for the bidentate P ligand 1,2-bis(di-tert-butylphosphino)ethane (dtbpe). The calculated elementary steps agree well with experimental findings: reaction barriers are reasonable and explain the facile liberation of acrylate from a nickelalactone by methyl iodide. We were able to isolate reactive intermediates and to verify the existence of proposed reaction pathways. Additionally, we have identified unproductive pathways leading to byproducts (e.g., propionates and catalytically inactive organometallic species). Although those side reactions can be suppressed to a certain extent, the strong binding of acrylate to nickel prevents a catalytic reaction, at least for the chosen ligand.

A set of heterogenized olefin-metathesis catalysts, which consisted of Ru complexes with the H(2)ITap ligand (1,3-bis(2',6'-dimethyl-4'dimethyl aminophenyl)-4,5-dihydroimidazol-2-ylidene) that had been adsorbed onto a silica support, has been prepared. These complexes showed strong binding to the solid support without the need for tethering groups on the complex or functionalized silica. The catalysts were tested in the ring-opening-ring-closing-metathesis (RO-RCM) of cyclooctene (COE) and the self-metathesis of methyl oleate under continuous-flow conditions. The best complexes showed a TON>4000, which surpasses the previously reported materials that were either based on the Grubbs-Hoveyda II complex on silica or on the classical heterogeneous Re(2)O(7)/B(2)O(3) catalyst.