Ring-expansion and desulfurisation of thiophenes with an aluminium(I) reagent.

Reactions of thiophene, 2-methylthiophene, 2-methoxythiophene, 2,3-dimethylthiophene, and benzothiophene with the aluminium(I) complex [{ArNC(Me)2H}Al] (Ar = 2,6-di-isopropylphenyl) are reported. In all cases, carbon-sulfur bond activation and ring-expansion of the heterocycle is observed. For thiophene, we identify a reaction network for desulfurisation that includes an unusual second carbon-sulfur bond activation step.

Anionic Magnesium and Calcium Hydrides: Transforming CO into Unsaturated Disilyl Ethers.

The synthesis, characterisation and reactivity of two isostructural anionic magnesium and calcium complexes is reported. By X-ray and neutron diffraction techniques, the anionic hydrides are shown to exist as dimers, held together by a range of interactions between the two anions and two bridging potassium cations. Unlike the vast proportion of previously reported dimeric group 2 hydrides, which have hydrides that bridge two group 2 centres, here the hydrides are shown to be "terminal", but stabilised by interactions with the potassium cations. Both anionic hydrides were found to insert and couple CO under mild reaction conditions to give the corresponding group 2 cis-ethenediolate complexes. These cis-ethenediolate complexes were found to undergo salt elimination reactions with silyl chlorides, allowing access to small unsaturated disilyl ethers with a high percentage of their mass originating from the C1 source CO.

C-H and C-F coordination of arenes in neutral alkaline earth metal complexes.

A series of neutral magnesium and calcium complexes bearing an extremely bulky diamido ligand have been synthesised and crystallographically characterised. A number of these complexes feature rare group 2 metalaromatic interactions, such as the η6-coordination of benzene and 'agostic-like' C-H coordination, the latter previously unseen in neutral Mg and Ca complexes.