Synthesis, structures, and catalytic activity of aluminum and zinc complexes chelated by 2-((2,6-dimethylphenyl)amino)ethanolate

Treatment of ArNHCH2CH2OH (HL, Ar=2,6-Me2C6H3) with AlMe3 and ZnEt2 resulted in the formation of a bi-aluminum complex, [(Me2Al)(L)](2) (1), and a tetra -zinc complex, [EtZn2(L)(3)](2) (2), respectively. They were characterized by elemental analysis, NMR, and single -crystal X-ray diffraction analysis. Complex 1 is a crystallographically centrosymmetric dimer with an Al2O2 core in the solid state, while a Zn4O6 core is observed in 2, which can be viewed as two side -by -side cubes missing a pair of opposite vertices. Preliminary catalytic activity tests indicated that the aluminum complex 1 was inactive for the ring -opening polymerization (ROP) of epsilon-caprolactone, while the zinc complex 2 was a highly active initiator for the ROP of epsilon -caprolactone and could control the molecular weight distribution of the resulted polymers in narrow ranges. CCDC: 2304200, 1; 2304201, 2.