A series of aluminum alkyl complexes nacnacRAlMe2 (2a–2h) bearing aliphatic N-substituted β-diketiminate ligands (nacnacRH = N,N′-dialkyl-2-amino-4-iminopent-2-enes), were prepared from the reaction of trialkyl aluminum and the corresponding β-diketimines. All these aluminum complexes were characterized by NMR, elemental analysis and HRMS spectroscopy. The molecular structures of complexes 2a, 2c and 2h were confirmed by single-crystal X-ray diffraction. These aluminum alkyl complexes show notable activity towards the ring-opening polymerization of ε-caprolactone in the absence and presence of alcohol, and the resulting polymers have narrow molecular weight distributions.

Treatment of the lithium salt of β-ketimine with FeCl2(THF)1.5 in the presence of LiN(SiMe3)2 and water affords the multimetallic iron(II)–lithium complex 1, [(LMe)2Fe]3Li2O [where LMe = MeC(O)CHC(NMe)Me]. In complex 1 three separated (LMe)2Fe units are bound together by one Li2O species, which leads to the formation of an interesting {Fe3Li2O} core structure. Complex 1 can be used as a single-component initiator for the ring-opening polymerization of ε-caprolactone at room temperature, achieving a monomer conversion of 98% within 100 min, and a narrow molecular weight distribution (PDI = 1.28) of the resulting polymer.

A series of aluminum alkyl complexes nacnacRAlMe2 (2a–2h) bearing aliphatic N-substituted β-diketiminate ligands (nacnacRH = N,N′-dialkyl-2-amino-4-iminopent-2-enes), were prepared from the reaction of trialkyl aluminum and the corresponding β-diketimines. All these aluminum complexes were characterized by NMR, elemental analysis and HRMS spectroscopy. The molecular structures of complexes 2a, 2c and 2h were confirmed by single-crystal X-ray diffraction. These aluminum alkyl complexes show notable activity towards the ring-opening polymerization of ε-caprolactone in the absence and presence of alcohol, and the resulting polymers have narrow molecular weight distributions.