Solid-state NMR and the thermal polymerization of 2,4-hexadiyne-1,6-diol bis-(p-toluenesulfonate)

Njus, Jeffrey M.; Sandman, Daniel J.

doi:10.1016/j.ssnmr.2005.07.005

Cited by 6 publications

(11 citation statements)

References 28 publications

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“…The methylene carbon resonance has been shown to be quite sensitive to a modication of the adjacent acetylenic moiety. 40 Especially, this resonance moves downeld upon transformation of the triple bonds into double bonds because of the disappearance of the shielding effect brought about by the triple bonds. Consequently, in our case, the observed shi is in accordance with the disappearance of the nearby acetylenic carbons.…”

Section: Resultsmentioning

confidence: 99%

Azole-functionalized diacetylenes as precursors for nitrogen-doped graphitic carbon materials

et al. 2013

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A novel strategy for the preparation of nitrogen-doped carbon is presented that is based on the use of azole-functionalized diacetylenic precursors (imidazole and benzimidazole). As demonstrated by thermal analyses (TGA, DSC) and spectroscopic measurements (IR, 13 C solid-state NMR), these diacetylenic molecules undergo exothermic polyaromatization at low temperature. This process is independent of the intrinsic ability of the diacetylenes to undergo solid-state topochemical polymerization. At 800 C, graphite-like structures incorporating nitrogen are obtained, as proven by XPS measurements. The nitrogen contents of the residues resulting from thermolysis at 800 C are fairly high, 7.4 and 8.4 wt%, and these percentages amount to about 4 wt% at 1100 C. This study also shows that mixing these diacetylenes with small amounts of FeCl 2 prior to pyrolysis at 800 C leads to porous carbon materials with relatively high surface areas, 253 and 281 m 2 g À1 . TEM photographs indicate that these porous carbon materials form graphitic nanostructures. Polydiacetylenes also decompose into graphite-like materials, and the degree of graphitization of these materials and their nitrogen contents are comparable to those of the residues obtained by pyrolysis of the diacetylene monomers. Thus, low molecular weight diacetylenic monomers are effective precursors to access graphite-like materials, and this process does not require the prior preparation of a polymer.

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Section: Resultsmentioning

confidence: 99%

Azole-functionalized diacetylenes as precursors for nitrogen-doped graphitic carbon materials

et al. 2013

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“…2,4-Hexadiyne-1,6-diol bis(p-toluenesulfonate), pTS (3), was made from 2,4-hexadiyne-1,6-diol according to a known procedure. 61 2,4-Hexadiyne-1,6-diol was prepared by oxidative dimerization of propargyl alcohol following reported protocols. 102,103 General considerations All of the syntheses involving air-sensitive materials were carried out under an inert atmosphere of argon using standard Schlenk-line techniques.…”

Section: Methodsmentioning

confidence: 99%

“…These new signals indicate the presence of a PDA with an enyne structure. 61,95 Furthermore, as observed previously by Sandman and co-workers in the case of poly-ETCD (ETCD = bis(ethyl)urethane of 5,7-dodecadiyne-1,12-diol), 95 poly-IPUDO (IPUDO = bis(isopropyl)urethane of 5,7-dodecadiyne-1,12diol), 95 and poly-pTS (pTS = 2,4-hexadiyne-1,6-diol bis(p-tolue- nesulfonate), 61 the resonance of the methylene groups adjacent to the triple bonds in the starting monomer has moved downfield by 10 ppm in the spectrum of the polymer. This shift is consistent with the fact that shielding of the CH 2 groups in the monomer by the nearby triple bonds no longer exists in the polymer.…”

Section: Polymerization Reactivity Ofmentioning

confidence: 99%

“…C NMR spectrum of the washed powder, the signals corresponding to the triple bonds of the monomer (δ = 68-74 ppm) are no longer observed and have been replaced by two new resonances at 103 and 128 ppm (Figure 16). These new signals indicate the presence of a PDA with an enyne structure 61,95. Furthermore, as observed previously by Sandman and co-workers in the case of poly-ETCD (ETCD = bis(ethyl)urethane of 5,7dodecadiyne-1,12-diol),95 poly-IPUDO (IPUDO = bis(isopropyl)urethane of 5,7-dodecadiyne-1,12-diol),95 and poly-pTS (pTS = 2,4-hexadiyne-1,6-diol bis(p-toluenesulfonate),61 the resonance of the methylene groups adjacent to the triple bonds in the starting monomer has moved downfield by 10 ppm in the spectrum of the polymer.…”

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confidence: 91%

“…60 Clearly, this synthetic procedure is inappropriate for large-scale preparations of 1, so we looked for a safer route. We have found that 1 forms when 2,4hexadiyne-1,6-diol bis(p-toluenesulfonate) 61 (3) is allowed to react with an excess of imidazole in refluxing dichloromethane (Scheme 2). 62 Chromatographic purification of 1 with use of a CH 2 Cl 2 -CH 3 OH solvent mixture (94 : 6 v/v) followed by slow evaporation of the solvents gives 1?H 2 O (2) in 55% yield.…”

Section: Introductionmentioning

confidence: 99%

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Stability and solid-state polymerization reactivity of imidazolyl- and benzimidazolyl-substituted diacetylenes: pivotal role of lattice water

et al. 2013

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International audience1,6-Bis(1-imidazolyl)-2,4-hexadiyne (1) and1,6-bis(1-benzimidazolyl)-2,4-hexadiyne (5) have beenpreparedby a novel method that consists in refluxing excess imidazole and benzimidazole with 2,4-hexadiyne-1,6-diol bis(p-toluenesulfonate),pTS (3). This procedure is a viable alternative to the widely used Hay coupling protocol in case the target diyne possesses substituents capable of deactivating the copper catalyst by complexation. Diyne1crystallizes as a hydrate,1?H2O(2). For this compound, water is essential toachieve a crystalline material, and attempts to obtain crystals without included solvent were unsuccessful. In the structure of2, the organic fragments organize around the water molecule and interact with it through a dense network of hydrogen bonds. The CMC-CMC moieties are not oriented suitably for topochemical polymerization, and when trying to alter the organizationof the crystal by heating so as to induce polymerization, water is lost in an abrupt fashion that leads to instantaneous decomposition into polyaromatic-like species. Similar results were observed when water was removedin vacuo at room temperature. The benzimidazole-containing compound can be crystallized with water molecules (4)orwithout(5). X-ray crystallography shows that the structure of 5is organized by numerous C-H...N, C-H...p,andimidazolyl...imidazolyl p-p interactions. The diacetylene molecules almost have the right arrangement for topochemical polymerization, withpossibly reactingCMC-CMC fragments not beingparallel, a rare situation indiacetylene chemistry. Yet, experiments showthat topochemical polymerizationdoes not occur. Incorporationofwater in the lattice of5leads toa solvate that is topochemically reactive. Unlike2, however, water molecules in 4are not isolated but are organized as ribbons. Spectroscopic characterization of the polymer of4indicates that it is a blue phase polymer, with water coordinated to it. This study shows that it is possible to use water, and more generally solvent molecules, to transform a nonreactive diacetylene into a reactive one, even though this approach is less predictable than the cocrystal approach developed by Fowler, Lauher, and Goroff. The solvate approach is simple to implement, quite versatile because of the large rangeof solvents available, andonedoes not face theproblemof having to remove the host in case one needs to recover the polymer. Previous studies describing a similar approach are scarce

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Symmetrical Diacetylenes Outfitted with Ionic Liquid-like Groups: Structural, Polymerization, and Carbonization Studies

Fahsi

Dumail

Viau

et al. 2023

Crystal Growth & Design

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Three symmetrical diacetylenes (DAs) bearing tetraalkylammonium substituents have been prepared, namely, 1,6-bis(triethylammonium)hexa-2,4-diyne diiodide (2), dinitrate (3), and bis[bis(trifluoromethylsulfonyl)imide] (4). For these three salts, the duality between polymerization and carbonization has been investigated, and the results have been rationalized in terms of solid-state organization and molecular structure. These DAs have been irradiated at 254 nm with concomitant annealing at 80 °C (4) or 110 °C (2 and 3), and the lack of polydiacetylene (PDA) formation is in agreement with the fact that the CC–CC rods do not have a suitable orientation for 1,4-addition. Compound 4 is an ionic liquid. This DA starts melting at 88 °C with a maximum peak value of 104 °C, as ascertained by differential scanning calorimetry and thermogravimetric analyses. It is stable in the liquid state at 120 °C for several hours and remains unchanged at 170 °C for a few minutes without any sign of PDA formation, which means that if some kind of organization exists in the liquid phase, it is not helpful for 1,4-polymerization. Thermolyses of 2–4 have been conducted under a nitrogen flow up to 220 °C (3) and 1200 °C (2 and 4). In all three cases, graphite-like carbon materials were obtained. The graphite-like structures start to form around 200 °C, which is the temperature at which cycloaromatization of the triple bonds takes place. The residues from the pyrolyses of 2 and 4 exhibit nitrogen contents of 1.75 and 1.40 wt %, respectively, and powder X-ray diffraction and Raman analyses indicate that these materials have coherently scattering domain sizes in the range of 1–3 nm depending on the crystallographic direction. The Brunauer, Emmett, and Teller specific surface area of 2@1200 derived from dinitrogen sorption experiments is 88 m2 g–1 and that of 4@1200 is 33 m2 g–1. These values are much higher than those measured in previous works for carbon residues prepared at 1100 °C from imidazolium- and benzimidazolium-appended diacetylenes, thereby highlighting the pivotal influence of the size of the cation on the microstructure of the resulting carbon material. In addition, 2@1200 appears to be mostly microporous and 4@1200 mesoporous, which suggests that the anion also plays a central part in the structuring of the final solid. Last, X-ray photoelectron spectroscopy analysis of 4@1200 indicates that, besides nitrogen, this residue also contains small amounts of fluorine and sulfur, thus making carbonization of ionic diacetylenes an alternative method to introduce doping elements in a graphite structure.

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Solid-state NMR and the thermal polymerization of 2,4-hexadiyne-1,6-diol bis-(p-toluenesulfonate)

Cited by 6 publications

References 28 publications

Azole-functionalized diacetylenes as precursors for nitrogen-doped graphitic carbon materials

Azole-functionalized diacetylenes as precursors for nitrogen-doped graphitic carbon materials

Stability and solid-state polymerization reactivity of imidazolyl- and benzimidazolyl-substituted diacetylenes: pivotal role of lattice water

Symmetrical Diacetylenes Outfitted with Ionic Liquid-like Groups: Structural, Polymerization, and Carbonization Studies

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