A Versatile and Highly Efficient Catalyst System for the Preparation of Polyesters Based on Lanthanide Tris(2,6-di-tert-butylphenolate)s and Various Alcohols

Lanthanum Tris(2,6-di-tert-butyl-4-methylphenolate) as a Novel, Versatile Initiator for Homo- and Copolymerization of Cyclic Carbonates and Lactones

“…The signals of ending groups (OCH(CH 3 ) 2 ) for both polyDTC and polyTMC show multiple peaks at 4.86 ppm and double peaks at 1.30 ppm in the 1 H NMR spectra. Such structural features reveal the acyl-oxygen bond cleavage and the "coordination-insertion" mechanism for all the three monomers initiated by La(OAr) 3 .…”

“…CL (Mitsubishi Chemical) was distilled under reduced pressure. La(OAr) 3 was synthesized according to the known method [6] and dissolved in toluene as 0.1 mol/L solution.…”

Rare earth metal initiated ring-opening polymerization of lactones

“…Feijen et al used in situ generated yttrium alkoxides as ROP initiators for CL and VL 81,82) . They developed a highly efficient initiator system based on Ln tris(2,6-ditert-butyl phenolate)s (Ln(t-BPO) 3 Ln = Sc, Y, La-Lu) and various alcohols as co-catalyst allowing excellent control over molecular weight and end group identity of the resulting PCL and PVL polymers.…”

Ring-opening polymerization of lactides using heterobimetallic yttrocene complexes

“…McLain et al have introduced the yttrium alkoxide Y(OCH 2 CH 2 NMe 2 ) 3 as a highly active initiator for the living ring-opening polymerization of L-lactide (L,Ldilactide) 3) . Subsequently, a series of other rare earth alkoxides such as Ln 5 (l 5 -O)(O i Pr) 13 (Ln = Y, La, Sm, Yb) have been studied and found to constitute a promising class of efficient initiators [4][5][6][7] . More recently we have found that the heterobimetallic yttrocene derivatives containing two linked amido-cyclopentadienyl ligands Li[Y(g 5 : g 1 -C 5 R 4 SiMe 2 NCH 2 CH 2 OMe) 2 ] (Scheme 1) are capable of efficiently polymerizing e-caprolactone.…”