Soluble Bimetallic μ-Oxo-alkoxides. 8. Structure and Kinetic Behavior of the Catalytic Species in Unsubstituted Lactone Ring-Opening Polymerization

Rare earth metal initiated ring-opening polymerization of lactones

“…ROP provides a more convenient route to the synthesis of polylactones as compared to the traditional step polycondensation method [6][7][8][9][10][11] . Macromolecular engineering of these polymers is gaining importance for the synthesis of telechelics, block, graft and star shaped polymers [12][13][14][15][16][17][18][19][20] . This, in turn, requires the synthesis of polyesters with predictable molecular weight from the initial molar ratio of initiator to monomer concentration, low polydispersity indices and control over end groups which is only possible with initiators having selectivity in terms of initiation, propagation, and termination reactions.…”

Ring-opening polymerization of ?-caprolactone initiated by rare earth complex catalysts

“…(Al, Zn) m-oxo alkoxides {(RO) 2 Al{O{ Zn{O{Al(OR) 2 }, [9][10][11][12][13] , with a coordination-insertion mechanism. With a PHB{O{AlEt 2 macPoly( 1-caprolactone) ( 21,22 In the present article, we focused on the study of Anhydrous yttrium chloride was prepared by…”

Novel Macromolecular Architectures Based on Aliphatic Polyesters: Relevance of the “Coordination-Insertion” Ring-Opening Polymerization

“…The most frequently encountered Lewis acid catalyst is undoubtedly the stannous 2-ethylhexanoate, currently referred to as stannous octoate (Sn(OCt) 2 ). On the other hand, when metal alkoxides containing free p-, d-, or forbitals of a favo poxide [13][14][15], tetraphenylporphinato aluminum alkoxides [16], and diethyl aluminum methoxide [17], respectively. Confirming the observed living character of the polymerization promoted by aluminum alkoxides, the extent of side reactions, mainly the "back-biting" ones, has been studied by Penczek et al, who have quantitatively described the degree of livingness by the so-called selectivity parameter (β).…”