title: Synthesis and structure of aluminium amine-phenolate complexes.
abstract: Reaction of Al(OiPr)3 with the tris-phenol amine ligand L1H3 in toluene at ambient temperature results in the formation of the iso-propanol adduct [HOiPr.Al(L1)]. Single crystal X-ray diffraction analysis reveals the structure to be a hydrogen bonded dimer. Reaction of Al(OiPr)3 (or AlMe3) with L1H3 in THF affords the related, and structurally characterised THF adduct, [THF.Al(L1)]. Similar reaction of Al(OiPr)3 (or AlMe3) with the bis-phenol amine and tetra-phenol diamine ligands, L2H3 and L3H4, results in the formation and isolation of the complexes [Al(L2)]2 and [Al(L3)H] respectively, both of which have been structurally characterised via single crystal X-ray diffraction studies. Reaction of the alkoxide bridged dimer [Al(L2)]2 with the strong Lewis base HMPA results in the formation of the monomeric HMPA adduct [HMPA.Al(L2)] which was also structurally characterised. The adduct [HOiPr.Al(L1)] and the dimer [Al(L2)]2 were tested for their activity in the ring-opening polymerisation (ROP) of rac-lactide under solvent-free conditions (130 degrees C). Under the conditions employed [Al(L2)]2 failed to produce polymer after 48 h, in stark contrast to [HOiPr.Al(L1)] which after 24 h and 48 h produced narrow molecular weight polymer (24 h: yield=25%, Mn=14500 and PDI=1.05; 48 h: yield=65%, Mn=47700 and PDI=1.06).
authors: Department of Chemistry, University of Bath, Bath, UK BA2 7AY. a.l.johnson@bath.ac.uk
authors: Andrew L
authors: AL
authors: Johnson
authors: Matthew G
authors: MG
authors: Davidson
authors: Yolanda
authors: Y
authors: Pérez
authors: Matthew D
authors: MD
authors: Jones
authors: Nicolas
authors: N
authors: Merle
authors: Paul R
authors: PR
authors: Raithby
authors: Stephen P
authors: SP
authors: Richards