Unsymmetrical diarylamido-based rare-earth alkyl complexes: their synthesis and catalytic performance in isoprene polymerization.
Dalton Trans
; 50(4): 1334-1343, 2021 Feb 07.
Article
in En
| MEDLINE
| ID: mdl-33411859
ABSTRACT
A family of rare-earth complexes bearing diarylamido-based pincer ligands with phosphino-, phenylthio- and quinolino-sidearms have been synthesized and fully characterized. Upon activation by [Ph3C][B(C6F5)4], the scandium (P-Sc and S-Sc) and yttrium complexes (P-Y and S-Y) could catalyze the polymerization of isoprene with cis-1,4 selectivity (up to 98.8%), while the lutetium analogues P-Lu and S-Lu produced trans-1,4 selective polyisoprene (up to 83.3%). Density functional theory (DFT) calculations were carried out to clarify the mechanisms for the metal-dependent stereoselective (cis to trans) polymerization of isoprene catalyzed by P-Sc, P-Y and P-Lu, suggesting that kinetically and thermodynamically more favorable insertion-isomerization during chain propagation is the key reason for P-Lu catalyzed trans-stereoselective isoprene polymerization.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Language:
En
Journal:
Dalton Trans
Journal subject:
QUIMICA
Year:
2021
Document type:
Article
Affiliation country: