Facile cleavage of the silicon-oxygen bond leading to unusual dinuclear aluminum complexes

Abstract

Reactions of Me2Si(OR)(NHR') (R = 2,6-Me2Ph; R' = Cy (2a) Ph (2b)) with AlMe3 in pentane at room temperature afford unusual dinuclear aluminum complexes (Me2Al)(2)(mu-OR)(mu-NR'SiMe3)] (R = 2,6-Me2Ph; R' Cy (3a), Ph (3b)) that contain both nitrogen- and oxygen-bridging groups. Meanwhile, the corresponding reaction of Me2Si(OR)(NHR') (R, R' = 2,6-Me2Ph (2c)) yields a monomeric N,O-chelated aluminum species [Me2Si(OR)(NR')]AlMe2 (3c). It is most likely that two AlMe3 molecules are associated with the facile cleavage of the Si-O bond to form the stable four-membered (mu-N)Al-2(mu-O) ring of 3a,b, but the analogous reaction does not occur in 2c, having a bulkier N-substituent. The crystal structure of 3a is reported.