H‐transfer reaction during decomposition of N‐(2‐methylpropyl)‐ N‐(1‐diethylphosphono‐2,2‐dimethylpropyl)‐N‐oxyl (SG1)‐based alkoxyamines

Edeleva, Mariya; Marque, Sylvain R. A.; Kabytaev, Kuanysh; Guillaneuf, Yohann; Gigmès, Didier; Bagryanskaya, Elena G.

doi:10.1002/pola.26500

Cited by 23 publications

(27 citation statements)

References 59 publications

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“…However, Bagryanskaya et al [35] proved that the hydroxylamine derivative from SG1 is unstable. The cyclic voltammogram of SG1 also proved the instability of the SG1 oxoammonium cation since its reversible reduction is not observed (Fig.…”

Section: Resultsmentioning

confidence: 99%

Stability of SG1 nitroxide towards unprotected sugar and lithium salts: a preamble to cellulose modification by nitroxide-mediated graft polymerization

Moreira¹,

Charles²,

Major³

et al. 2013

Beilstein J. Org. Chem.

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SummaryThe range of applications of cellulose, a glucose-based polysaccharide, is limited by its inherently poor mechanical properties. The grafting of synthetic polymer chains by, for example, a “grafting from” process may provide the means to broaden the range of applications. The nitroxide-mediated polymerization (NMP) method is a technique of choice to control the length, the composition and the architecture of the grafted copolymers. Nevertheless, cellulose is difficult to solubilize in organic media because of inter- and intramolecular hydrogen bonds. One possibility to circumvent this limitation is to solubilize cellulose in N,N-dimethylformamide (DMF) or N,N-dimethylacetamide (DMA) with 5 to 10 wt % of lithium salts (LiCl or LiBr), and carry out grafted polymerization in this medium. The stability of nitroxides such as SG1 has not been studied under these conditions yet, even though these parameters are of crucial importance to perform the graft modification of polysaccharide by NMP. The aim of this work is to offer a model study of the stability of the SG1 nitroxide in organic media in the presence of unprotected glucose or cellobiose (used as a model of cellulose) and in the presence of lithium salts (LiBr or LiCl) in DMF or DMA.Contrary to TEMPO, SG1 proved to be stable in the presence of unprotected sugar, even with an excess of 100 molar equivalents of glucose. On the other hand, lithium salts in DMF or DMA clearly degrade SG1 nitroxide as proven by electron-spin resonance measurements. The instability of SG1 in these lithium-containing solvents may be explained by the acidification of the medium by the hydrolysis of DMA in the presence of LiCl. This, in turn, enables the disproportionation of the SG1 nitroxide into an unstable hydroxylamine and an oxoammonium ion.Once the conditions to perform an SG1-based nitroxide-mediated graft polymerization from cellobiose have been established, the next stage of this work will be the modification of cellulose and cellulose derivatives by NMP.

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Section: Resultsmentioning

confidence: 99%

Stability of SG1 nitroxide towards unprotected sugar and lithium salts: a preamble to cellulose modification by nitroxide-mediated graft polymerization

Moreira¹,

Charles²,

Major³

et al. 2013

Beilstein J. Org. Chem.

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“…Taking into account the data available in the literature, several tentative assumptions can be provided to describe the unexpected inefficiency of 1 as initiator for the NMP of isoprene: Compound 1 is a powder exhibiting low solubility in isoprene at room temperature. Thus, upon warming, it might be partly solved as aggregates with intermolecular H‐bonding providing lower homolysis than expected;By‐products issued from the decomposition of 1 might play the role of inhibitors as it was shown that they were very different from the conventional by‐products of alkoxyamine decomposition;It might occur that the stabilizants or impurities in isoprene turn 1 into its carboxylate salt, [84] which exhibits slower decay.…”

Section: Discussionmentioning

confidence: 99%

“…By‐products issued from the decomposition of 1 might play the role of inhibitors as it was shown that they were very different from the conventional by‐products of alkoxyamine decomposition;…”

Section: Discussionmentioning

confidence: 99%

Hydrogen‐Bonding Effects for the C–ON Bond Homolysis and Reformation Reactions of Alkoxyamines

Bagryanskaya

Brémond

Butscher

et al. 2014

Macro Chemistry & Physics

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International audienceN-(2-methylpropyl)-N-(1-diethylphosphono-2,2-dimethylpropyl)-O-(2-carboxyprop-2-yl) hydroxylamine (BlocBuilder MA) is, among the commercially available alkoxyamines, one of the most efficient for nitroxide-mediated polymerization (NMP). However, recent results have shown that it does not perform well for the NMP of isoprene. The occurrence of intramolecular hydrogen bonding (IHB) between the carboxylic function and the diethoxyphosphoryl group has been proposed as the reason for its low efficiency. In this article, the presence of this IHB is confirmed using IR, P-31 NMR, P-31-H-1 HOESY, and DFT calculation results. The solvent effect on this IHB and consequently on k(d) values is also investigated. However, combining kinetic analysis and rate measurements in various solvents, the influence of this IHB on the C-ON bond homolysis and reformation in alkoxyamine is shown to be very weak

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“…The descriptive example here could be H‐atom transfer reaction in NMP. Even 3% of H‐atom transfer reaction can stop the monomer conversion at 5% …”

Section: Pdimentioning

confidence: 99%

Enhanced spin capturing polymerization: Numerical investigation of mechanism

Nikitin

Parkhomenko

Edeleva

et al. 2015

J. Polym. Sci. Part A: Polym. Chem.

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Simulation on the kinetic scheme of enhanced spin capturing polymerizations (ESCP) were performed to reveal the influence of different parameters, e.g., initiation rate, spin capturing and side reactions on the properties (the monomer conversion, degree of polymerization, polydispersity index, and the fraction of “living” chains) of polymer obtained. The kinetic scheme of ESCP was solved numerically as well as the method of statistical moments of molecular weight distribution was applied to get some numerical expressions for analysis. The simulations showed that fast initiation rate can lead to decrease of living fraction and broadening of molecular weight distribution. Whereas high rate of spin capturing makes the polymer chains shorter but increases living character. And side reactions always decrease livingness of the polymer obtained. Finally in the case of absence of side reaction we were able to formulate criteria for formation of polymer with target molecular weight and quota of living chains via ESCP process. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015, 53, 2546–2556

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H‐transfer reaction during decomposition of N‐(2‐methylpropyl)‐ N‐(1‐diethylphosphono‐2,2‐dimethylpropyl)‐N‐oxyl (SG1)‐based alkoxyamines

Cited by 23 publications

References 59 publications

Stability of SG1 nitroxide towards unprotected sugar and lithium salts: a preamble to cellulose modification by nitroxide-mediated graft polymerization

Stability of SG1 nitroxide towards unprotected sugar and lithium salts: a preamble to cellulose modification by nitroxide-mediated graft polymerization

Hydrogen‐Bonding Effects for the C–ON Bond Homolysis and Reformation Reactions of Alkoxyamines

Enhanced spin capturing polymerization: Numerical investigation of mechanism

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