Zwitterionic bis(phenolate)amine lanthanide complexes for the ring-opening polymerisation of cyclic esters

Abstract

The reaction of Sm{N(SiMe3)2}3 with the bis(phenol)amines H2O2N(R) (H2O2N(R) = RCH2CH2N(2-HO-3,5-C6H2(t)Bu2)2; R = OMe, NMe2 or Me) gave exclusively zwitterions Sm(O2N(R))(HO2N(R)). For R = OMe or NMe2 these were efficient catalysts for the ring-opening polymerisation of epsilon-caprolactone and D,L-lactide with a tendency to form cyclic esters; in contrast, no polymerisation was observed for R = Me.

Synthesis, Structure, and C–C Cross‐Coupling Activity of (Amine)bis(phenolato)iron(acac) Complexes

“…[1][2][3][4][5][6][7][8][9][10] Also, group 3 and lanthanide metal complexes of these ligands have been effective as catalysts or initiators for ring-opening polymerization of lactide and ε-caprolactone. [11][12][13][14][15][16] By comparison, there has been limited use of (amine)bis(phenolato) ligands with the first row late transition metals, [17][18][19][20][21][22][23][24] whereas the chemistry of monoanionic phenoxytriamine ligands with these metals is far more developed. [25][26][27][28][29][30][31][32][33][34][35] We are interested in the development of new inexpensive, non-…”

Zinc Complexes of Piperazinyl‐Derived Aminephenolate Ligands: Synthesis, Characterization and Ring–Opening Polymerization Activity

“…Various ligands of this type have been used in main group and early transition metal chemistry (including lithium, [2][3] magnesium, [4][5][6][7][8][9][10] calcium, [11] rare-earths, [12,13] , zinc, [1,[14][15][16][17]19] aluminum, [18,20] zirconium [21,22] and titanium. [23] ) Many of these complexes have been reported to be excellent initiators for ring-opening polymerization (ROP) of cyclic esters such as rac-lactide.…”

Ring-opening polymerization of ε-caprolactone by lithium piperazinyl-aminephenolate complexes: synthesis, characterization and kinetic studies

“…1 Various ligands of this type have been used in main group and early transition metal chemistry (including lithium, 2-7 magnesium, [8][9][10][11][12][13][14] calcium, 15 rare-earths, 16,17 zinc, [18][19][20][21][22][23][24][25][26][27] aluminum, [28][29][30] zirconium 31,32 and titanium 33 ). Many of these complexes have been reported to be excellent initiators for the ring-opening polymerization (ROP) of cyclic esters such as lactide and ε-caprolactone.…”