Controlled ring‐opening homo‐ and copolymerization of ɛ‐caprolactone and d, l‐lactide by iminophenolate aluminum complexes: An efficient approach toward well‐defined macromonomers. Issue 9 (6th February 2014)

• Record Type: Journal Article
• Authors: Zaitsev, Kirill V.; Piskun, Yulia A.; Oprunenko, Yuri F.; Karlov, Sergey S.; Zaitseva, Galina S.; Vasilenko, Irina V.; Churakov, Andrei V.; Kostjuk, Sergei V.
• Is Part Of: Journal of polymer science. Volume 52:Issue 9(2014:May)
• Page Start: 1237
• Page End: 1250
• Publication Date: 2014-02-06
• Subjects: biomaterials -- block copolymers -- diblock copolymers -- living polymerization -- metal‐organic catalysts -- macromonomers -- polyesters -- ring‐opening polymerization -- X‐ray; 547
• DOI: 10.1002/pola.27110
• Languages: English
• ISSNs: 0887-624X

Abstract

ABSTRACT: The aluminum complexes containing two iminophenolate ligands of the type ( p ‐XC6 H4 NCHC6 H4 O‐ o )2 AlR' (R′=Me (3, 4 ) or R′=O(CH2 )4 OCH=CH2 (5, 6 ), X=H (3, 5 ), F(4, 6 )) were synthesized and characterized by 1 H, 13 C NMR spectroscopy, and X‐ray crystallography. The reaction of AlMe3 with two equivalents of substituted iminophenols gave five‐coordinated {ONR}2 AlMe (3, 4 ) complexes. Subsequent reaction of these methyl complexes with unsaturated alcohol, HO(CH2 )4 OCH=CH2, resulted in target compounds 5 and 6 in a good yield. It was shown that the complexes (3 ‐6 ) are monomeric in solution (NMR) and in solid state (X‐ray analysis). The catalytic activity of the complexes 5 and 6 towards ring‐opening polymerization (ROP) of ɛ‐caprolactone and d, l ‐lactide was assessed. Complex 5 showed higher activity as compared with 6, while both of these catalysts induced controlled homo‐ and copolymerization to afford the macromonomers with high content of vinyl ether end groups ( F n > 80%) in a broad range of molecular weights ( M n = 4000–30, 000 g mol −1 ) with relatively narrow MWD ( M w / M n = 1.1–1.5). © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014, 52, 1237–1250 Abstract : The investigation of the synthesis and structure of aluminum complexes based on iminophenolate ligands (L2 AlMe and L2 AlOCH2 (CH2 )4 OCH=CH2 ) and their reactivity in the ring‐opening homo‐ and copolymerization of ɛ‐caprolactone and D, L ‐lactide in bulk has been performed. These compounds initiate controlled ring‐opening polymerization (ROP) of E‐caprolactone and D, L ‐lactide, affording macromonomers with a high content of vinyl ether end groups (up to 100%) and with relatively narrow polydispersity.