Cu-catalyzed polymerization

The overall reaction rate and the rate constant of the electron-transfer step are summarized in Table 17 for the polymer-Cu-catalyzed oxidation of substrates such as 2,6-dimethylphenol (XOH) and ascorbic acid15 . The ks values for polymer-Cu-catalyzed oxidation are larger than those for monomeric-Cu-catalyzed oxidation. Particularly in the oxidative polymerization of XOH, it is obvious that the electron-transfer step is accelerated by polymer ligands, and the large value of ke is in agreement with the higher rate of polymer-Cu-catalyzed polymerization. Therefore, the... 

The mechanism indicated in Figure 1 is postulated for the clay-catalyzed polymerization of phenols through radical cations. According to this scheme, an acceptor for one electron, such as Cu(II)... 

The Cu+ catalyzes the formation of radicals from the cumene hydroperoxide, which then begins the polymerization of the TEGMA and TEGMA molecules with only one reactive end (Figure 19.7). Those with two active ends result in the formation of cross-linked materials. A similar reaction occurs with iron and several metals such as zinc, gold, silver, cadmium, magnesium, titanium, and alloys that contain any of these metals. 

A series of eight closely related N,0-based hgands was used to imravel possible steric and electronic influences in the copper-catalyzed polymerization of 2,6-dimethylphenol [248]. Applying a biphasic toluene/water emulsion, with an in situ prepared Cu(Melm)-catalyst (Melm = 1-methylimidazole),... 

Variations on this process include atom transfer polymerization (ATRP), "" which includes metal catalyzed atom transfer, to give the propagating radical as illustrated in Scheme 3 for Cu(I) catalyzed polymerization of styrene using 1-arylethyl chlorides. 

Allyltri-n-butylstannane (EC-2) similarly terminates the copper-catalyzed polymerization of MA to give allyl-functionalized polymers via elimination of the stannyl group accompanying the bromine originated from the dormant polymer terminal.346 Allyl a -end PMMA was obtained also by the copper-catalyzed reaction between allyl bromide (EC-3) and the isolated bromine-capped PMMA, although the functionalization was 57%.226 Another allyl derivative (EC-4) similarly leads to methacrylate-based macromonomers quantitatively in the presence of Cu(0).347... 

Organoboron polymers containing transition metals (Ni, Pd, Pt) and pyrazaboles were obtained by Cu-catalyzed coupling polymerization. The Ni- and Pt-containing polymers showed MLCT (metal-to-ligand charge transfer) absorption.78... 

Based on the above achievements, the group of Habaue systematically studied Cu-catalyzed asymmetric oxidative coupling polymerization reactions. 

The PPEs [14, 35, 36], which are dehydrogenated analogs of the poly(p-phenylene vinylene) s, display desirable optoelectronic properties that have found extensive use as emissive materials [37, 38]. PPE preparation is dominated by the Sonogashira Pd/Cu-catalyzed cross-coupling of aryl haUdes and terminal alkynes [39]. However, polymerizations under these conditions rarely achieve a high molecular weight, and defects such as diyne formation and alkyne crosshnking in the polymer backbone are endemic [14, 40]. Alkyne metathesis was envisioned as a complementary method to PPE synthesis, with much success. 

Since metals such as Fe, Zn, Sn, and Cu catalyze dehydrochlorination, the free radical polymerization must be carried out in glass or stainless steel vessels. 

Binder and Kluger [41, 42] utilized the Hamilton wedge and THY as molecular recognition handles in the construction of side-chain-functionalized poly(oxanorbornene dicarboximides) using a ROMP/click methodology. Monomers functionalized with azido or alkynyl side chains were polymerized to either homopolymers or block copolymers and subsequently subjected to Cu-catalyzed azide-alkyne cycloaddition [72] to install the desired H-bonding motifs. 

Hecht and co-workers developed another class of polymers based on allgme-azide click chemistry. The synthesis of these new polymers was an A2-I-B2 step-growth polymerization, with A2 corresponding to the 2,6-diethynylpyridine monomer and B2 to the 3,5-diazidohenzoate monomer that reacted together under Cu-catalyzed 1,3-dipolar cycloaddition reaction conditions (Figure 5.22). 

Matyjaszewski, K. (1998). Radical nature of Cu-catalyzed controlled radical polymerizations (atom transfer radical polymerization). Macromolecules, 3/(15) 4710-4717. 

The aliphatic components of suberin form polyester domains that are attached to the phenolics as indicated above (see Fig. 6.4.7). Activated cu-hydroxy acids and dicarboxylic acids are probably involved in the esterification as shown in cutin biosynthesis (232). It was proposed that the long-chain fatty alcohols found in suberin might be incorporated into the suberin polymer by peroxidase-catalyzed polymerization of phenylpropanoic acid esters of these alcohols (232), such as the ferulic acid esters of C18-C28 alcohols frequently found in suberin-as-sociated waxes (Table 6.4.2). 

Transition metal-catalyzed polymerizations are supposed to involve an AT process. In a copper-catalyzed ATRP, for example, a complex Cu(I)X/L, where X is a halogen (Br or Cl) and L is a ligand, is used as an activator A, and the complex Cu(II)X2/L acts as a persistent (stable) radical AX (Scheme 3b). The basic kinetic features of ATRP closely resemble those of NMP in theory. 

With other metal alkoxides, such as n(Ot-Pr)4 and Sn (Oi-Pr)4, Ru-1 induced faster polymerizations of MMA than Al(Ot-Pr)3, though the MWDs became slightly broader. Aluminum acetylacetonate [Al(acac)3] was a mild alternative additive that did not induce an ester-exchange reaction between the ester group and the monomer or monomer units in the polymer chain, which might occur using aluminum alkoxides. These metal alkoxides were also effective for other metal complexes, such as iron, nickel, rhenium, and copper. " It is noteworthy that Al(Oi-Pr)3 could even make the Cu(II) species active, in which the controlled polymerizations of styrene, MMA, and ethyl acrylate were possible." " Ti(Oi-Pr)4 was also efficient for the half-metallocene Fe(II)-catalyzed polymerizations, as will be mentioned in Seaion 3.13.3.1.2." Based on calculation studies by Poli et the nature of Al(Oi-Pr)3 in the... 

With the rich chemical properties of alkyne monomers, polymers with rare and complicated stmctures can be designed and synthesized via alkyne-based polymerizations. For instance, polyamidines are a series of important polymers with potential roles as biomaterials, metallic conductors, and photosensitive semiconductors their syntheses are limited to two-component, step-growth polymerization reactions [37, 38]. An efficient Cu-catalyzed MCR of alkynes, sulfonyl azides, and amines was recently reported by Chang and coworkers to afford a library of small-molecule amidines [3, 5], The reaction undergoes a Cu-catalyzed azide-alkyne... 

Thankfully, numerous experts have kindly agreed to provide up-to-date chapters on several aspects in the area, thereby contributing to a collection of recent developments. In the first chapter, Ryohei Kakuchi discusses the use of metal-catalyzed MCRs for the synthesis of polymers. Special attention is laid to Cu-catalyzed developments. In the second chapter, Rongrong Hu and Ben Zhong Tang summarize developments of multi-component polymerizations of alkynes and... 

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