Lanthanide organometallic and coordination chemistry
The lanthanide ions are characterised by their large ionic radii, the essentially ionic bonding in and lability of their complexes and their tendency to bind hard N- or O-donor ligands. We are interested in the behaviour of complexes of lanthanide(II) and lanthanide(III) ions with soft C- and/or P-donor ligands. We have shown that both homoleptic and heteroleptic alkyl and phosphide complexes are accessible and that these frequently exhibit highly unusual structures and reactivities.
Key results from the MgC labs in this area include: (i) the synthesis of the first sigma-bonded organometallic complex of Sm(II) and the isolation of the first crystallographically characterised complex of the benzophenone ketyl radical anion, (ii) the synthesis of some of the first lanthanide(II) phosphide complexes, (iii) the isolation of a novel, cyclometalated lanthanum phosphidoalkyl complex and its conversion into a rare cationic organolanthanum(III) compound, and (iv) the observation of an unusual ligand rearrangement leading to a unique La(III) ate complex.
The unique properties of the lanthanide ions frequently lead to highly unusual reactions for our compounds. For example, the reaction between YbI2 and two equivalents of the potassium phosphide [{(Me3Si)2CH}(C6H4-2-OMe)P]K does not give the corresponding Yb(II) bis(phosphide). Instead, the ligand undergoes an unusual rearrangement, generating an ytterbium(II) heterocubane cluster containing an alkoxo-phosphide dianion [[{(Me3Si)2CH}(C6H4-2-O)P]Yb(THF)]4. This is just one example of a wide array of interesting reactions and rearrangements that we have observed in lanthanide alkyl and phosphide chemistry.
