Electron paramagnetic resonance study of the reaction of ground-state aluminium atoms with a series of ethers in a rotating cryostat

Abstract

Ground-state Al atoms react with symmetric cyclic and acyclic ethers at 77 K in a rotating cryostat to give a host of mononuclear organoaluminium compounds. Magnetic parameters determined from EPR spectra given by Al atoms and acyclic ethers are consistent with the formation of novel C—C and C—H aluminium atom insertion products. A third species has been tentatively assigned to the product given by Al atom insertion into the C—O bond. In addition a carbon-centred radical is formed by loss of a hydrogen atom from carbon adjacent to the alkoxyl group. In contrast the cyclic ethers are resistant to alumino hydride formation and in most cases a carbon radical resulting from ring opening at the C—O bond is formed. Mono- and di-ligand complexes, Al[ether] and Al[ether]₂, are tentatively identified and may be the primary intermediates for all the reactions that occur.