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.

This review considers noncovalent bonds between divalent chalcogen centers. In the first part we present X-ray data taken from the solid state structures of dimethyl- and diphenyl-dichalcogenides as well as oligoalkynes kept by alkyl-sulfur, -selenium, and -tellurium groups. Furthermore, we analyzed the solid state structures of medium sized (12-24 ring size) selenium coronands and medium to large rings with alkyne and alkene units between two chalcogen centers. The crystal structures of the cyclic structures revealed columnar stacks with close contacts between neighboring rings via noncovalent interactions between the chalcogen centers. To get larger space within the cavities, rings with diyne units between the chalcogen centers were used. These molecules showed channel-like structures in the solid state. The flexibility of the rings permits inclusion of guest molecules such as five-membered heterocycles and aromatic six-membered rings. In the second part we discuss the results of quantum chemical calculations. To treat properly the noncovalent bonding between chalcogens, we use diffuse augmented split valence basis sets in combination with electron correlation methods. Our model substances were 16 dimers consisting of two Me-X-Me (X = O, S, Se, Te) pairs and dimers of Me-X-Me/Me-X-CN (X = O, S, Se, Te) pairs. The calculations show the anticipated increase of the interaction energy from (Me-O-Me) (-2.15 kcal/mol) to (Me-O-Me/Me-Te-CN) (-6.59 kcal/mol). An analysis by the NBO method reveals that in the case of the chalcogen centers O and S the hydrogen bridges between the molecules dominate. However, in the case of Se and Te the major bonding between the pairs originates from dispersion forces between the chalcogen centers. It varies between -1.7 and -4.0 kcal/mol.

Close contacts between sulfur, selenium, and tellurium centers are used to construct nanotubes in the solid state which are able to host other molecules.

Under visible-light irradiation, the gold-catalyzed intermolecular difunctionalization of alkynes with aryl diazonium salts in methanol affords a variety of α-aryl ketones in moderate to good yields. In contrast to previous reports on gold-catalyzed reactions that involve redox cycles, no external oxidants or photosensitizers are required. The reaction proceeds smoothly under mild reaction conditions and shows broad functional-group tolerance. Further applications of this method demonstrate the general applicability of the arylation of a vinyl gold intermediate instead of the commonly used protodemetalation step. This step provides facile access to functionalized products in one-pot processes. With a P,N-bidentate ligand, a stable aryl gold(III) species was obtained, which constitutes the first direct experimental evidence for the commonly postulated direct oxidative addition of an aryl diazonium salt to a pyridine phosphine gold(I) complex.

Terminal 1,2-dialkynylarenes undergo an unexpected cyclization hydroarylation reaction toward naphthalene derivatives in benzene as the solvent. The regioselectivity of the reaction can be controlled by careful catalyst tuning. Also, the preparation of a bench-stable cationic amine complex or simple heterogenization of the catalyst on neutral aluminum oxide, which enables efficient catalyst recycling, was possible. Intensive mechanistic investigations were undertaken, giving new insights into the so-far underestimated role of acetylides in gold chemistry. The gold plays a fascinating dual role serving to both catalyze the reaction and activate the substrate by Au−C-σ bond formation. Evidence of gem-diaurated compounds playing an important part for gold catalysis is also reported.