Living polymerization of phenylacetylene by rhodium-based ternary catalysts, (diene)Rh(I) complex/vinyllithium/phosphorus ligand. Effects of catalyst components

Abstract

It was proved that a Rh‐based ternary catalyst composed of [(nbd)RhCl]2 (nbd: bicyclo[2.2.1]hepta‐2,5‐diene), (triphenylvinyl)lithium, and triphenylphosphine induces living polymerization of phenylacetylene. [(nbd)RhCl]2 was effective as the main catalyst, whereas neither [(cod)RhCl]2 (cod: 1,5‐cyclooctadiene) nor [(coe)2RhCl]2 (coe: cyclooctene) induced living polymerization. The anionic ligands such as chlorine, methoxy, and acetoxy groups in the Rh complex hardly affected the living polymerization. When vinyllithium as second catalyst component possessed a bulky substituent such as phenyl or t‐butyl group on its α‐carbon, stable vinylrhodium species were generated, which led to living polymerization. At least one substituent was necessary on the β‐carbon of the vinyllithium for the living polymerization. Tris(4‐substituted phenyl)phosphines worked well as third components among various phosphorus ligands. The polymerization was decelerated as the basicity of the phosphine ligand increased.

Rhodium(I)‐α‐Phenylvinylfluorenyl Complexes: Synthesis, Characterization, and Evaluation as Initiators in the Stereospecific Polymerization of Phenylacetylene

“…72 %. A more detailed examination of the ligand components in this system was subsequently reported by Misumi et al [6] The first reported isolable Rh I -vinyl complexes from this family of catalysts came from Miyake, Misumi and Masuda. not requiring the use of a lithiated unsaturated species in its synthesis.…”

“…Under these conditions the resulting PPA has a theoretical M n of 25,000 at 100 % monomer conversion. The low activity is surprising; however, Misumi and co-workers [6] reported that for similar species such as (1,2-diphenyl)vinyl lithium, while still maintaining a generally low dispersity. 1 H NMR spectroscopic analysis of the obtained PPA indicated that it was highly stereoregular with a calculated [14] cis content of 96 %.…”

“…Interestingly, while meeting the general structural requirements for such Rh I species able to initiate the polymerization of PA quantitatively these new fluorenyl species exhibited markedly reduced efficiencies suggesting that the structural requirements of the vinyl ligand extend beyond simple substitution patterns [6] to include geometric considerations. Intrigued by the paucity of reported well-defined isolable Rh I complexes able to mediate the (co)polymerization of PA effectively we recently established a program of research aimed at investigating the synthesis and application of new organo-Rh I complexes based on the general Masuda structural motif with the aim of investigating the effect of the structure of the vinyl initiating fragment.…”

Durch definierte Rhodiumkomplexe vermittelte Polymerisationen

“…Nach diesem ersten Bericht publizierten Misumi et al . eine detaillierte Studie zu den Auswirkungen jeder Komponente in solchen ternären katalytischen Systemen.…”

Stereochemistry of Polymerization

“…2-14j). Various substituted acetylenes such as phenylacetylene have also been studied [Kanki et al, 2002;Misumi et al, 2000].…”