Symmetrical Diacetylene Research Articles

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

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.

Synthesis of New Conjugated Diynes Containing Carbamate Groups, and Study of Their Properties.

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Synthesis of New Conjugated Diynes Containing Carbamate Groups, and Study of Their Properties

Carbamates of monoacetylene and diacetylene series were synthesized and characterized. A catalytic system CuI-pyrrolidine was applied for the first time to a synthesis of symmetrical diacetylenes by oxidative dimerization of terminal acetylenes. The comparative activity of diynes obtained was studied in the photoinitiated solid-phase topochemical polymerization. Diyne carbamates undergoing thermal polymerization were obtained for the first time.

Synthesis and cytotoxic activity of a series of diacetylenic compounds related to falcarindiol.

The synthesis of a series of diacetylenic compounds related to the natural product falcarindiol has been carried out. Unsymmetrical diacetylenes were prepared by a modification of the Cadiot-Chodkiewicz coupling reaction, while a Glaser coupling was used to prepare symmetrical diacetylenes. These compounds have been tested for in vitro cytotoxic activity against Hep-G2, and H-4-II-E cell lines. Diacetylenes with additional unsaturation at C-1, 2, appended with hydroxyl groups at C-3 and C-8, or with long hydrophobic chains, exhibited IC50 values in the micromolar range.

Chemical and electrochemical polymerisation of diacetylenes containing thienyl moiety as the side group

Two symmetrical diacetylene monomers containing thienyl moiety as the side groups, namely 1,4-bis(2'-thienyl)butadiyne and 1,4-bis(3'-thienyl)butadiyne, are reported which have been successfully polymerised electrochemically. They have also been polymerised chemically in solution using Lewis acid as initiator. The resulting polymers have been characterised by elemental analysis, infrared spectra, absorption spectra and by solid state NMR spectra. The polymers were found to have conjugated π-electron structure and both of them show high environmental stability. The properties of the polymers have been compared with that of poly(3-methylthiophene) which is a conventional and much studied conjugated polymer. The electrical conductivity of the polymers has also been investigated.

Monomeric pNBS: Bis(p-nitrobenzenesulfonate) of 2,4-Hexadiyne

The title compound, 2,4-Hexadiyne-1,6-diyl bis(p-nitrobenzenesulfonate) (pNBS), C18H12N2O10S2, is a symmetrical di-para-substituted diacetylene R—C C—C C—R where R is –CH2—O—SO2—C6H4—NO2. In this compound, the volume of the NO2 group is 23.0 A3, almost equal to that of a CH3 group (23.5 A3) in the well known polymerizable symmetrical diacetylene, 2,4-hexadiyne-1,6-diyl bis(p-toluenesulfonate) (pTS). pNBS, however, crystallizes in an unreactive monomeric form.

Preparation and Solution Polymerization of Diacetylenes

Polymeric Diacetylenes (Polydiacetylenes, or PDA's) are being investigated for their Non-Linear Optical (NLO) properties. PDA's have also been advocated by Patel and Yang (J. Chem. Educ. 1983, 60, 181-5) as a system for teaching polymer science, although these authors did not publish a synthesis of the diacetylene precursor to their PDA in this article. Most published student laboratory syntheses of symmetrical diacetylenes follow Hay's procedure (J. Org. Chem. 1962, 27, 3320-1), with some modifications for using air as a source of oxygen. We report a simpler procedure, which has been useful in preparing a variety of diacetylenes. Yields range from 35-70%, and may be improved by increasing the reaction time. In addition, we have developed conditions suitable for solution polymerization of these diacetylenes to PDA's, using short-wave UV light. These conditions complement the solid phase polymerization conditions described by Patel and Yang.

ポリジアセチレン系非線形光学材料の合成

In order to obtain the materials with large third-order nonlinear optical properties, polydiacetylenes (PDAs) having π-conjugation between polymer backbone and substituents were synthesized by proper crystal engineering. For the monomers for PDAs aromatic rings directly bound to main chain, one of two substituents bonding to the diacetylene (DA) moiety was selected from those of non-polymerizable symmetrical DA monomers. The highest χ (3) and the expected smallest dihedral angle between the polymer backbone and aromatic rings was already realized in one of the derivatives. PDAs with acetylenic and diacetylenic groups directly bound to the main chain were synthesized by polymerization of triyne and tetrayne compounds, respectively. The diacetylenic substituents of the polymers from the latter ones could be polymerized to give di (polydiacetylene) s, where two PDA polymer backbones were conjugated.

Structure of Novel Symmetrical and Unsymmetrical Diacetylenes

Abstract Some preliminary solid-state properties of a new symmetrical diacetylene and an unsymmetrical derivative with toluene sulfonate side groups are reported. The unsymmetrical compound presents a stable non polymerizable form and a metastable polymerizable one.

Synthesis, Polymerization and X-ray Structure (Monomer and Polymer) of the Unsymmetrical Diacetyle-Ne pTS-pFBS

Abstract Some preliminary results on the new unsymmetrical diacetylene pTS-pFBS are presented. pTS-pFBS is the disubstituted molecule R‒C˭C‒C˭C‒R’ where R is CH3-Ph-SO3-CH3O and R’ is F-Ph-SO2-CH2O, R and R’ being respectively the side groups of the well known symmetrical diacetylenes pTS and pFBS. Synthesis, crystallization and thermal polymerization data are described. The X-ray crystal structures of monomer and polymer pTS-pFBS had been determined at 143 K and are discussed in terms of particular reflections.