Intramolecular Agostic Interactions and Dynamics of a Methyl Group at a Preorganized Dinickel(II) Site.

Alkyl nickel intermediates relevant to catalytic processes often feature agostic stabilization, but relatively little is known about the situation in oligonickel systems. The dinickel(I) complex K[LNi], which is based on a compartmental pyrazolato-bridged ligand L with two β-diketiminato chelate arms, or its masked version, the dihydride complex [KL(Ni-H)] that readily releases H, oxidatively add methyl tosylate to give diamagnetic [LNi(CH)] () with (Ni···Ni) ≈ 3.7 Å.

A Mathematical Model for the Take-Off in Platform Diving.

In platform diving the take-off phase is of outstanding importance in order to achieve both a high level of performing quality and a high degree of difficulty. The diver has to produce the right forces and direction of the center of mass (COM) in order to attain the required angular momentum and dive height. To support the development of an optimum take-off technique, the Institute for Applied Training Science designed a dryland measuring and feedback system.

Reductive Binding of Nitro Substrates at a Masked Dinickel(I) Complex and Proton-Coupled Conversion to Reduced Nitroso Ligands.

The transition-metal-mediated reductive activation of nitro compounds and subsequent proton-coupled N-O bond cleavage reactions are key steps of important processes such as the commercially relevant conversions of nitroaryls to aniline derivatives. Here we report the reactivity of selected nitro substrates RNO (R = Me, Ph, -CHCHO) with pyrazolate-based dinickel(II) dihydride complexes [ML(NiH)] (M = Na, K); the latter eliminate H upon substrate binding and serve as a masked dinickel(I) platform. The products [MLNi(ONR)] (R = Me, -; R = Ph, -) host a κ,κ' bridging twice deprotonated dihydroxy amine [RNO] within the dinickel pocket, and structural analysis as well as NMR evidence show that the alkali cation (Na or K) is closely associated with the reduced substrate.