Living polymerization of 2-butyne using a well-characterized tantalum catalyst

Wallace, Kevin C.; Liu, Andy H.; Davis, W. M.; Schrock, Richard R.

doi:10.1021/om00105a011

Cited by 110 publications

(87 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%

“…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.…”

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confidence: 98%

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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%

mentioning

confidence: 98%

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

Katsumata

Shiotsuki

Kuroki

et al. 2005

Polym J

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“…For instance, a Ta carbene was prepared and the living polymerization of 2-butyne was achieved by using the Ta carbene. 54 Although polymers from symmetric acetylenes are usually insoluble, solvent-soluble poly(2-butyne) is accessible if the degree of polymerization is suppressed below 200. Further, Mo carbene catalysts were synthesized and proven to elegantly induce living cyclopolymerization of 1,6-heptadiynes.…”

Section: Metathesis Mechanismmentioning

confidence: 99%

Substituted polyacetylenes

Masuda

2006

J. Polym. Sci. A Polym. Chem.

392

222

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This article reviews the chemistry of substituted polyacetylenes developed by our research group, more specifically, development of polymerization catalyst, synthesis of new polymers, elucidation of their structure, investigation of their properties, and development of their functions. The main features are as follows: a number of catalysts based on group 5, 6, and 9 transition metals (Nb, Ta, Mo, W, and Rh) have been developed, which include living polymerization catalysts. By using these catalysts, many new substituted polyacetylenes have been synthesized, whose molecular weights are very high (Mw = 104−106). Most of the polymers are soluble in many common solvents and stable enough in the air unlike polyacetylene. Some of these polymers exhibit interesting functions including high gas permeability and photoelectronic properties. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 165–180, 2007

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“…Thus, Ta(=CHBu t )(OAr) 3 (THF) reacts with RC=CR (R = Me, Ph, or TMS) to yield the corresponding, THF-free, metallacyclobutene complexes Ta(CR=CRC-HBu l )(OAr)3. 372 The substituted metallacyclobutenes Ta(CR=CRCHBu t )(OAr) 3 ( R = Me or Ph) are decomposed in the presence of pyridine by a four-electron, electrocyclic process to provide the vinylalkylidene complexes. 372 These compounds are in equilibrium with their corresponding metallacyclobutenes as indicated in Scheme 32.…”

Section: Alkene and Alkyne Polymerizationmentioning

confidence: 99%