Significant enhancement of catalytic properties in mononuclear yttrium complexes by nitrophenolate‐type ligands: Synthesis,structure, and catalysis for lactide polymerization |
| |
| Authors: | Yu‐Chia Su Ting‐Yu Chiu Yun‐Ting Liu Po‐Heng Lin Bao‐Tsan Ko |
| |
| Abstract: | The syntheses, structures, and catalytic properties for lactones polymerization of eight novel yttrium complexes containing an amine‐bis(benzotriazole phenolate) ( C1NN BiBTP ) ligand are reported. A series of nitrophenolate (NP)‐type of ligands possessing R substituents with variable electronic properties (R = NO2, Cl, H, CH3) on ortho and/or para position attached to the phenolate rings have been selected and further reacted with C1NN BiBTP ‐H2 proligand and YCl3·6H2O. Two series of complexes, Y( C1NN BiBTP )(TNP)(MeOH)2] ( 3 ), Y( C1NN BiBTP )(2,4‐DNP)(MeOH)2] ( 4 ) and Y( C1NN BiBTP )(2,5‐DNP)(MeOH)2] ( 5 ) with two MeOH molecules as initiators as well as Y( C1NN BiBTP ‐H)(CNP)2] ( 6 ), Y( C1NN BiBTP ‐H)(2‐NP)2] ( 7 ) and Y( C1NN BiBTP ‐H)(MNP)2] ( 8 ) with two NP derivatives, were synthesized. Their ring‐opening polymerizations of L‐ lactide (L‐ LA) were investigated for all complexes in order to further understand the correlations between the inductive effect of substitutions and catalytic properties. Particularly, the activity and controllability of yttrium complexes 3 and 5 were improved dramatically comparing with the literature complex with the similar coordination environment, Y( C1NN BiBTP )(NO3)(MeOH)2], which can be a successful example to enhance the catalytic properties by exchanging coordinate molecules. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019, 57, 2038–2047 |
| |
| Keywords: | ring‐opening polymerization catalysts polyesters |
|
|
