Mimicking the CO-Bound State of the [Ni,Fe]-CO Dehydrogenase.

Complexes, where a doubly reduced CO (carbonite) ligand is spanned between a nickel(II) centre and a transition metal(II) ion (TM=Fe, Co, Zn) have been accessed. In non-coordinating solvents the carbonite ligand exhibits a flexible coordination behaviour as observed by NMR spectroscopy and supported by DFT calculations. In particular the [Ni-CO-Fe] representative replicates the respective entity in an intermediate formed during CO-conversion by the enzyme [Ni,Fe]-CODH in many ways (structure, spectroscopic properties, reactivity).

Appropriation of group II metals: synthesis and characterisation of the first alkaline earth metal supported transition metal carbonite complexes.

Nickel carbonite complexes supported by alkaline earth metals have been accessed salt-metathesis of the corresponding alkali metal precursors. The new complexes undergo Schlenk-like exchange reactions in solution which have been investigated by NMR spectroscopy. Also their reactivity towards epoxides and carbon monoxide was studied.

Controlling the Activation at Ni-CO Moieties through Lewis Acid Interactions in the Second Coordination Sphere.

Nickel complexes with a two-electron reduced CO ligand (CO , "carbonite") are investigated with regard to the influence alkali metal (AM) ions have as Lewis acids on the activation of the CO entity. For this purpose complexes with Ni(CO)AM (AM=Li, Na, K) moieties were accessed via deprotonation of nickel-formate compounds with (AM)N(Pr). It was found that not only the nature of the AM ions in vicinity to CO affect the activation, but also the number and the ligation of a given AM.

Preprogrammed assembly of supramolecular polymer networks via the controlled disassembly of a metastable rotaxane.

In our daily life, some of the most valuable commodities are preprogrammed or preassembled by a manufacturer; the end-user puts together the final product and gathers properties or function as desired. Here, we present a chemical approach to preassembled materials, namely supramolecular polymer networks (SPNs), which wait for an operator's command to organize autonomously. In this prototypical system, the controlled disassembly of a metastable interlocked molecule (rotaxane) liberates an active species to the medium.

A strained intramolecular P/Al-FLP and its reactivity toward allene.

FLPs featuring aluminum-phosphane interactions, spring-loaded by a rigid biphenylene linker, have been accessed through a route where trimethyltin units at phosphane-functionalized organic backbones are exchanged by an AlCl moiety. Upon contact with substrates like CO these are readily bound by the Al/P site with release of strain. The system could also be utilized for a unique reactivity, namely the activation of allene.