Stereospecific catalytic precision polymerization of 2-vinylpyridine via rare earth metal-mediated group transfer polymerization with 2-methoxyethylamino-bis(phenolate)-yttrium complexes

Abstract

2-Methoxyethylamino-bis(phenolate)-yttrium complexes were employed in the catalytic precision polymerization of 2-vinylpyridine (2VP). The C 1 -symmetric catalyst systems are able to isospecifically polymerize prochiral 2-vinylpyridine with moderate to high activities. Tacticities ranging from atactic to isotactic can be achieved (P m = 0.54-0.74). Mechanistic studies through 13 C NMR microstructure analysis of the resulting isotactic P2VP show an enantiomorphic site control mechanism.

Yttrium‐Catalyzed Synthesis of Bipyridine‐Functionalized AB‐Block Copolymers: Micellar Support for Photocatalytic Active Rhenium‐Complexes

“…As expected, changing the initiator to a bipyridine did not impact the normalized turnover frequencies (TOF*) in comparison to catalyst 1 since the activity is determined in the propagation step and is solely influenced by the metal center and the ligand, which are identical in all complexes ,. As the tacticity is also determined in the propagation step, catalyst 2 and 3 produce atactic P2VP with the same tacticity as catalyst 1 (SI, Figure S5) …”

Metal‐Catalyzed Group‐Transfer Polymerization: A Versatile Tool for Tailor‐Made Functional (Co)Polymers

“…revealed an impact of the steric bulk in the ortho ‐position of the phenolate rings on the isotacticity of the resulting P2VP. Isotacticities up to 92 % were reached with a bis(phenolate) catalyst bearing a tris(3,5‐dimethylphenyl)methyl‐moiety . With regard to the stereospecific polymerization of DMAA, the 2‐aminoalkoxy‐bis(phenolate)yttrium complexes and the before mentioned a nsa ‐zirconocenium complexes are the only catalysts that produce highly isotactic PDMAA with isotacticities up to 99 % in a living polymerization …”

C–H Bond Activation of Silyl-Substituted Pyridines with Bis(Phenolate)Yttrium Catalysts as a Facile Tool towards Hydroxyl-Terminated Michael-Type Polymers

“…Since the first polymerization attempts, various organocatalysts, metallocenes and non-metallocenes 8-membered cyclic intermediate [1][2][3][4][5][6][7][8]. Since the first polymerization attempts, various organocatalysts, metallocenes and non-metallocenes were established for the synthesis of highly precise, tailor-made and functional polymers [3,5,[7][8][9][10][11][12][13][14]. The scope of available 1,4-Michael-type monomers ranges from differently substituted acrylates, methacrylates, acrylamides or nitrogen bearing monomers (e.g., 2-vinyl pyridine (2VP)) to vinyl lactone systems and phosphorous containing monomers, i.e., dialkyl vinyl phosphonates (DAVP) [5,7,15,16].…”

“…These catalysts were able to overcome the obstacles and produced high molecular weight polymers with very narrow molecular weight distributions and were in addition able to induce stereoinformation [10,15,[17][18][19][20][21]. This enhanced performance was achieved by e.g., introducing highly sterically demanding ligands to non-metallocenes for stereoregular polymerization of MMA or 2VP [9,10,21], by controlled polymerization of vinyl phosphonates using non-metallocenes, frustrated Lewis pairs or trivalent metallocenes [12,14,15,17,[22][23][24] or by utilizing C-H bond activation to obtain catalysts with higher initiator efficiencies [18]. Further to this, the synthesis of block copolymers was facilitated due to the living character of this polymerization type by simple sequential addition of different monomers with respect to their coordination strength to the metal center [7,25,26].…”