Difunctionalized indol-2-yl-ligated bimetallic rare-earth metal complexes: synthesis, characterization and high activity towards polymerization of 2-vinylpyridine

• Published in: New journal of chemistry 2024-08, Vol.48 (33), p.1469-14696
• Main Authors: Zhao, Zhiwei, Tong, Yao, Liu, ChenCheng, Huang, Zeming, Wang, Shaowu, Wang, Fenhua
• Format: Article
• Language: English
• Subjects: Bimetals; Chemical synthesis; Coordination compounds; Erbium; High temperature; Lutetium; NMR spectroscopy; Polymerization; Rare earth elements; Toluene; Ytterbium; Yttrium
• ISSN: 1144-0546; 1369-9261
• DOI: 10.1039/d4nj02131b

A series of bimetallic rare-earth complexes {[μ-η 1 :(μ-η 1 :η 1 ):η 1 -1-(2-C 5 H 4 N)-3-(2-C 7 H 4 NS)C 8 H 4 N]RE(CH 2 SiMe 3 ) 2 } 2 (RE = Y( 7a ), Er( 7b ), Yb( 7c ), Lu( 7d )) were synthesized by treatment of rare-earth metal trialkyl complexes RE(CH 2 SiMe 3 ) 3 (THF) 2 with one equiv. of the proligand 1-(2-C 5 H 4 N)-3-(2-C 7 H 4 NS)C 8 H 5 N ( 6 ) in good isolated yields. Complex 7c can be converted to the divalent rare-earth metal complexes (η 4 :σ:κ 1 - L ) 2 Yb II [ L = 1-(2-C 5 H 4 N)-3-(2-C 7 H 4 NS)C 8 H 4 N(CHSiMe 3 )] ( 8 ) at elevated temperature in toluene solution. Complexes 7a , 7d and 8 were characterized by NMR spectroscopy. Additionally, the yttrium ( 7a ), erbium ( 7b ) and lutetium ( 7d ) complexes exhibited high activity in the polymerization of 2-vinylpyridine with isotactic selectivity and high molecular weight. A series of difunctionalized rare-earth metal alkyl complexes bearing 1-(2-pyridinyl)-3-(2-benzothiazolyl) indol-2-yl ligand were prepared and applied for polymerization of 2VP with high isotactic selectivity and high molecular weight.