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Journal of the Chilean Chemical Society

On-line version ISSN 0717-9707

Abstract

ZHANG, YU; PANG, XUAN; MA, LILI  and  TANG, ZHAOHUI. AN ALUMINUM SILOXIDE COMPLEX FOR STEREOSELECTIVE POLYMERIZATION OF RACEMIC LACTIDE. J. Chil. Chem. Soc. [online]. 2017, vol.62, n.2, pp.3468-3471. ISSN 0717-9707.  http://dx.doi.org/10.4067/S0717-97072017000200009.

Stereoselective polymerization of lactide is receiving growing attention in polymer science. Herein, a five-coordinate aluminum siloxide complex, [2,2-dimethyl-1,3-propylenebis(3,5-di-tert- butylsalicylideneiminato)] (triphenyl-silanolato) aluminium (III) (1), was prepared from AlEt3, N,N'-(2,2-dimethylpropylene) bis(3,5-di-tert-butylsalicylideneimine) and triphenyl-silanol. X-ray analysis demonstrated that 1 contained a five-coordinate aluminum atom with distorted trigonal bipyramidal geometry in the solid state. 1H NMR and 13C NMR spectra indicated that the two conformational stereoisomers of 1 tautomerizes rapidly in chloroform or toluene solution at room temperature. 1 showed high stereoselectivity (Pm = 0.84) for the ROP of rac-lactide in toluene at 100°C, and polymerized rac-lactide to crystalline polymer (Tm = 178°C). This is the first report of stereoselective polymerization of rac-lactide using aluminum siloxide as a catalyst.

Keywords : aluminum siloxide; catalyst; lactide; stereoselective; polymerization.

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