Aluminium Complexes of a Sterically Demanding Bis(iminophosphorane)methandiide

Abstract

The reaction of the sterically demanding bis(iminophosphorane)methane, {DipN=P(Ph2)}2CH2, H2L 1 (where Dip = 2,6-iPr2C6H3), with one or two equivalents of AlMe3 in toluene under varying conditions led to the methanide complex [HLAlMe2] 4, and the methandiide complex [L(AlMe2)2] 5, respectively. Iterative iodination of complex 5 with I2 in toluene yielded the complexes [L(AlMeI)2] 6 and [L(AlI2)2] 7. The complexes 4–7 were structurally characterised. The methanide 4 forms a puckered six-membered ring without Al-C(methanide) contact and the complexes 5 and 6 show coordination of the methandiide ligand to two Al atoms forming two four-membered rings on the central spirocyclic carbon centre. Complex 7 shows an asymmetric coordination mode of the two Al centres to the methandiide ligand in the solid state with an almost planar, severely distorted three-coordinate methandiide carbon atom and only one short Al–C bond.