Synthesis and Structural Characterisation of Dinuclear Aluminium Complexes Supported by NNO‐Tridentate Schiff‐Base Ligands and Their Catalysis in the Ring‐Opening Polymerisation of ϵ‐Caprolactone

Abstract

In this study, we prepared a series of dinuclear aluminium complexes {Bis{2-OAlMe 2 -3-CH 2, and Bis{2-OAlMe 2 -3-CH=N[2-N(CH 3 ) 2 C 6 H 4 ]-5-CH 3 C 6 H 2 }CH 2 } as well as their corresponding mononuclear aluminium compounds derived from NNO-tridentate Schiff-base ligands. The compounds were characterised by 1 H and 13 C spectroscopy and elemental analyses. Complexes 4 and 7 were additionally characterised by single-crystal X-ray diffraction. Their activities toward the ring-opening polymerisation (ROP) of ε-caprolactone (ε-CL) were investigated. In the presence of benzyl alcohol (BnOH), these complexes are catalytically active for the ROP of ε-CL. The kinetic studies for the polymerisation catalysed by these complexes indicated that the polymerisation was well controlled and produced polymers within a narrow molecular weight distribution. At low monomer concentrations, the catalytic activity of binuclear complexes is considerably greater than that of mononuclear complexes.

Efficient ring-opening polymerization of epsilon-caprolactone catalyzed by iron(III) chloride under mild reaction conditions

“…Metal complexes are one of the most e cient catalysts for the ROP of ε-CL [7]. Various metal species, including Sn [8-10], Zn [11][12][13], Ti [14][15][16], Al [17][18][19] etc, have been reported.…”