Living Coordination Polymerization of Alkoxyallenes by π-Allylnickel Catalyst. 2. Effect of Anionic Ligands on Polymerization Behavior and Polymer Structure

Abstract

The coordination polymerization of (n-octyloxy)allene (2) was carried out by π-allylnickel catalysts possessing various carboxylate ligands (1a−1c). The electronic character of the carboxylate ligand strongly influences the polymerization. Electron-withdrawing groups provide a living system that produces polymers with well-defined molecular weights and narrow molecular weight distributions in high yields. Without electron-withdrawing substituents, the reaction produces oligomeric byproducts. The ratio of 1,2- to 2,3-polymerization unit in the polymer increased with the electron-withdrawing character of carboxylate ligands. π-Allylnickel catalysts bearing halide ligands (1d, 1e, and 1f/Na2S2O3) also gave polymers from 2 in high yields, in which the polymerization rate, the microstructure, and the molecular weight distributions (M w/M n) of polymers were dependent upon the specific halide. The catalyst with chloride (1d) afforded a polymer with narrow M w/M n (1.03), possessing the ratio of 1,2- to 2,3-polymerization unit of 6:94, whereas with iodide (1f/Na2S2O3), the polymerization took place much faster to give a polymer (1,2-:2,3-polymerization unit = 16:84) with a little broader M w/M n (1.10).

SET‐LRP synthesis of PMHDO‐g‐PNIPAM well‐defined amphiphilic graft copolymer

“…To overcome these problems, Endo et al developed the living coordination polymerization of allene derivatives, which could provide well-defined polymers with high yields using [(g 3 -allyl)NiOCOCF 3 ] 2 as initiator. [41][42][43][44][45][46][47][48] Furthermore, block copolymers of allene derivatives were prepared by using two stages of monomer feeding due to the stability of living p-allylnickel end group 49 and the reactive pendent groups in allene derivatives such as hydroxyl were kept for the following modification. 45 Nevertheless, most kinds of copolymers containing polyallene segment can not be prepared by this kind of Ni-catalyzed living polymerization because [(g 3 -allyl)NiOCOCF 3 ] 2 can only initiate the polymerization of butadiene, isocyano monomers, and allene derivatives.…”

Trialkoxysilyl‐Functionalized Silver(I) Carboxylates: New Building Blocks for the Synthesis of Immobilizable and Immobilized Homogeneous Catalysts

“…Yield: 615 mg (99 %). C 14 Diisopropylamine (590 μL, 4.2 mmol) was added dropwise to a solution of hexafluoroglutaric anhydride (2) (577 μL, 4.2 mmol) in dichloromethane (30 mL) and the reaction mixture was stirred for 1 h at room temperature. Aqueous HCl (6 m, 20 mL) was added and the reaction mixture was stirred for an additional 10 min.…”

“…In addition, electron-withdrawing carboxylates have proven superior in various catalytic processes. [12][13][14] In this contribution, we report on the synthesis and spectroscopic properties of two new partly fluorinated trialkoxysilyl-substituted silver(i) carboxylates with a type A backbone. A related fluorinated silver(i) carboxylate lacking the silyl group has been prepared for comparison, and unusual structural features of these complexes in the solid state are described.…”

Synthesis of PS-b-PPOA-b-PS triblock copolymer via sequential free radical polymerization and ATRP

“…Polyallenes can be obtained by different polymerization approaches of allene derivatives including radical, cationic, coordination, and zwitterionic polymerization etc . In particular, Tomita et al developed Ni‐catalyzed living coordination polymerization of allene derivatives to provide well‐defined polymers with controlled molecular weights and narrow molecular weight distributions under mild conditions using [( η 3 ‐allyl)NiOCOCF 3 ] 2 as initiator . Block copolymerization of allene derivatives also can be conducted because of the stability of living π‐allylnickel end groups and the molecular weights of the corresponding block copolymers could be tuned by the feeding ratio .…”

“…2 In particular, Tomita et al developed Ni-catalyzed living coordination polymerization of allene derivatives to provide well-defined polymers with controlled molecular weights and narrow molecular weight distributions under mild conditions using [(g 3 -allyl)NiOCOCF 3 ] 2 as initiator. [3][4][5][6][7][8][9] Block copolymerization of allene derivatives also can be conducted because of the stability of living p-allylnickel end groups and the molecular weights of the corresponding block copolymers could be tuned by the feeding ratio. 10,11 Moreover, block copolymers [12][13][14][15][16][17][18] of allene derivatives with butadiene, isocyanides, or 3-hexylthiophene have been synthesized by sequential feeding because all these monomers can also be polymerized with [(g 3 -allyl)NiOCOCF 3 ] 2 .…”