Indium phosphasalen catalysts showing high isoselectivity and activity in racemic lactide and lactone ring opening polymerizations

Abstract

Study of a series of phosphasalen indium alkoxide complexes reveals that the substitution pattern at the phosphorus atoms can deliver outstanding isoselectivity with high rates.

Controllable preparation and performance of bio-based poly(lactic acid-iminodiacetic acid) as sustained-release Pb2+ chelating agent

“…Catalyst seriously affects the performance, yield, and appearance of the product ( Yuntawattana et al., 2020 ). It can be seen from Table 1 that the P(LA- co -IDA) synthesized by using SnO as catalyst has the highest intrinsic viscosity and relatively high yield, and its appearance is like white powder.…”

Towards a selective synthetic route for cobalt amino acid complexes and their application in ring opening polymerization of rac-lactide

“…This is most likely due to slow initiation rates relative to propagation rates, usually observed for poor nucleophilicity and sterically hindered initiating group. 9,14 Alternatively, experiments were carried out incorporating one equivalent of BnOH which could undergo fast and reversible reaction exchange between free alcohol and ligands, improving the initiation rate efficiency (Table 2, entries 7 & 8). Interestingly, presence of an exogenous alcohol, was found to both increase polymerization times and impart a signicant decrement on catalytic activity.…”

“…[1][2][3][4][5] PLA is most efficiently synthesized by ring opening polymerization (ROP) of rac-lactide (LA) using homogeneous metal complexes as initiators or catalyst. 6 The most active and selective complexes contain metal centers of Al(III), 7 Fe(II) 8 In(III), 9,10 Zn(II) [11][12][13] and Y(III). 14 Cobalt based catalysts have been widely used in polymerization reactions and more recently as bio-inspired photocatalysts, [15][16][17][18][19][20][21][22] but they are far less investigated in ROP of cyclic esters.…”

Towards Advances in Molecular Understanding of Boric Acid Biocatalyzed Ring-Opening (Co)Polymerization of δ-Valerolactone in the Presence of Ethylene Glycol as an Initiator

“…For ring expanded monomers, boric acid catalyzed homopolymerisation of δ-valerolactone and copolymerisation of δ-valerolactone with ε-caprolactone initiated by benzyl-alcohol have previously been reported by us and Ren et al, respectively [ 17 , 18 ]. The most widely used industrial catalysts for ring-opening polymerization of cyclic esters is tin (II) octanoate [Sn (Oct) 2 ]; however, several types of other metal catalysts such as aluminum alkoxides, calcium ammoniate, phosphasalen indium and zinc butoxides are also used [ 19 , 20 , 21 , 22 , 23 , 24 ]. Consequently, the use of non-metallic boric acid organocatalyst has not been exploited extensively in the ring expansion reaction of higher lactones polymers; however, it alleviates problems with the rigorous work-up required to obtain a polymer sample free of a residual trace of metals, which could interfere in a bioassay [ 25 ].…”