Bis(oxazoline)-derived N-heterocyclic carbene ligated rare-earth metal complexes: synthesis, structure, and polymerization performance. Issue 39 (20th July 2018)

• Record Type: Journal Article
• Authors: Pan, Yu; Zhao, Aijing; Li, Yang; Li, Wenqiang; So, Yat-Ming; Yan, Xiaoming; He, Gaohong
• Is Part Of: Dalton transactions. Volume 47:Issue 39(2018)
• Page Start: 13815
• Page End: 13823
• Publication Date: 2018-07-20
• Subjects: Chemistry, Inorganic -- Periodicals; Chemistry, Physical and theoretical -- Periodicals; Chemistry, Inorganic -- Periodicals; 546.05
• DOI: 10.1039/c8dt02130a
• Languages: English
• ISSNs: 1477-9226

Abstract

Abstract : Bis(oxazoline)-derived NHC supported rare-earth complexes have been synthesized for the first time and showed good activity for 1-hexene (co)polymerization. Abstract : Bis(oxazoline)-derived N-heterocyclic carbene (IBiox) supported rare-earth (Sc, Y, Lu) trialkyl complexes have been synthesized and structurally characterized, and their catalytic activity in the (co)polymerization of α-olefins has been studied. The treatment of Ln(CH2 SiMe3 )3 (THF)2 with one equivalent of freshly prepared IBiox afforded the rare-earth metal complexes (IBiox)Ln(CH2 SiMe3 )3 THF n (Ln = Sc (1 ), n = 0; Y (2 ), n = 1; and Lu (3 ), n = 1) in good yields. Single crystal X-ray diffraction study showed that1 is pseudo tetrahedral, while2 and3 are distorted trigonal bipyramidal with coordinated THF. The Ln–C(carbene) bond distances in1, 2, and3 are 2.352, 2.550, and 2.479 Å, respectively. DFT calculations were performed to study the bonding scheme and the structural stability. Complex1 showed a high activity for 1-hexene polymerization by activation with 2 equivalents of [Ph3 C][B(C6 F5 )4 ], and the resultant polymers are predominantly vinylene end groups ( ca. 95%). Moreover, the catalyst system based on1 proved to be effective for the copolymerization of 1-hexene with 1, 7-octadiene, affording the copolymers with about 20% pendant vinyl groups. The hydrophilicity of the copolymers was improved by modifying the vinyl groups with carboxyls via a thiol–ene reaction.