Direct polymerization of acetylene to give living polyenes

Schlund, Rüger; Schrock, Richard R.; Crowe, William E.

doi:10.1021/ja00202a046

Cited by 90 publications

(42 citation statements)

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“…With increasing temperature, the polymer yield tended to increase, while the M n of polymer decreased. Thus, the polymer yield increased to 24% at 80 C, while only methanol-soluble oligomers formed at 120 C (runs 2, 3 4,5). This suggests that methanol-soluble oligomers are mainly formed at high catalyst concentrations.…”

Section: Polymerization Of Monomermentioning

confidence: 94%

Polymerization of Substituted Acetylenes by the Grubbs–Hoveyda Ru Carbene Complex

Katsumata

Shiotsuki

Kuroki

et al. 2005

Polym J

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ABSTRACT:Polymerization of various mono-and disubstituted acetylenes was investigated by using GrubbsHoveyda catalyst (1). Hexyl propiolate (2) and 1-phenyl-2-(p-trimethylsilyl)phenylacetylene (3) Substituted polyacetylenes have been gathering much attention due to their potential applications to material-separation membranes, and optoelectronic and related fields.1 These polymers have been obtained by polymerization of corresponding acetylenic monomers in the presence of transition metal catalysts. Catalysts including group 5 and 6 transition metal and Rh have traditionally been employed to induce their polymerization. Among them, halides of early transition metals such as TaCl 5 , NbCl 5 , MoCl 5 , and WCl 6 in conjunction with organometallic cocatalysts polymerize various mono-and disubstituted acetylenes to give high molecular weight polymers in good yield. Some well-defined Ta, Mo, and W carbenes, so-called Schrock carbenes, induce living polymerization of substituted acetylenes. [2][3][4][5] This implies that the group 5 and 6 transition metal-catalyzed polymerization proceeds by the metathesis mechanism. One of the drawbacks of the early transition metal is that they are readily deactivated by polar groups in the monomer and polymerization solvents because of their high oxophilicity.Another type of catalysts frequently used for the polymerization of substituted acetylenes are rhodium (Rh) catalysts. Rh catalysts can polymerize only monosubstituted acetylenes such as phenylacetylene and its ring-substituted derivatives, 6-11 N-propargylamides, 12-17 and propiolic esters. [19][20][21][22][23] The Rh-catalyzed polymerization proceeds by the insertion mechanism, and features excellent tolerance to polar subsituents in the monomer 24,25 and protic solvents. 26 The Rh-based polymers generally possess high cis stereoregularity, which is indispensable for the formation of helical structures of poly(N-propargylamide)s. 12-17A huge number of studies on the synthesis and catalysis of ruthenium (Ru) carbene complexes have been reported in these several years. Ru carbene complexes represented by Grubbs' first-and secondgeneration catalysts exhibit high activity in olefin metathesis reactions such as ring-opening metathesis polymerization (ROMP), ring-closing metathesis (RCM), cross metathesis (CM). 27 Compared to early transition metal-based metathesis catalysts, Ru carbene complexes display tolerance against protic functional groups in these metathesis reactions as well as considerable stability to oxygen and moisture. It should also be noted that many Ru complexes have well-defined carbene structures, which enables to directly generate carbene-type active species without adding cocatalysts. The Grubbs' second-generation complex reportedly reacts with diphenylacetylene stoichiometrically to afford 3 -vinylcarbene complex, which is regarded as an intermediate of the polymerization of acetylenes.28 Ru-catalyzed polymerizations of acetylene 29 and diyne compounds 30,31 have recently been reported. Though an Ru carbene ...

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Section: Polymerization Of Monomermentioning

confidence: 94%

Polymerization of Substituted Acetylenes by the Grubbs–Hoveyda Ru Carbene Complex

Katsumata

Shiotsuki

Kuroki

et al. 2005

Polym J

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“…In terms of microstructure, poly(DEDPM) prepared with 1 or 2 consists virtually solely (> 95 %) of 1,3-cyclopent-1-enylenevinylene units, as shown by 13 C NMR spectroscopic measurements. [17,18] Energy band gaps were calculated from the absorption maximum (l max ) [27] and are summarized in Table 1. The polymerization mechanism certainly follows that of molybdenum-catalyzed cyclopolymerizations and is shown in Scheme 1.…”

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confidence: 99%

Simple Synthesis of Poly(acetylene) Latex Particles in Aqueous Media

et al. 2003

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“…Dessen Austausch durch den 2,4,5-Trimethoxybenzyliden-Liganden [25] führte zu [Ru(CF 3 COO) 2 (CH-(2,4,5-(MeO) 3 Wie 13 C-NMR-Messungen belegen, besteht Poly-(DEDPM), das mit 1 oder 2 hergestellt wurde, hinsichtlich der Mikrostruktur praktisch ausschließlich (> 95 %) aus 1,3-Cyclopent-1-enylenvinylen-Einheiten. [17,18] Die Bandlücken wurden aus den Absorptionsmaxima (l max ) berechnet [27] und sind in Tabelle 1 zusammengefasst. Der Polymerisationsmechanismus kann sicher ähnlich wie der von Molybdän-katalysierten Cyclopolymerisationen formuliert werden und ist in Schema 1 zusammengefasst.…”

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