- Structures of the Polymers Obtained by the Solid-State Polymerization of Diyne, Triyne, and Tetrayne with Long-Alkyl Substituents
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Structures of the polymers obtained by solid-state polymerization of diyne, triyne, and tetraynes substituted by long chain alkyl groups were investigated by solid-state 13C NMR spectroscopy.Assignments of all peaks in the spectra were made successfully, referring to those of the monomers and the polydiacetylenes of known structures.It was clearly shown that the backbone of these polymers has always the same structure of .This fact suggests that only 1,4-addition polymerization takes place in the similar way for the diyne, the triyne and the tetraynes, excluding many other possible addition schemes, and the tetraynes give an interesting polydiacetylene with butadiynyl substituents.This exclusive 1,4-addition can be explained in terms of topochemical control.
- Okada, Shuji,Hayamizu, Kikuko,Matsuda, Hiro,Masaki, Atsushi,Nakanishi, Hachiro
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- Scope and reaction mechanism of an aerobic oxidative alkyne homocoupling catalyzed by a di-copper-substituted silicotungstate
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The di-copper-substituted γ-Keggin-type silicotungstate TBA 4[γ-H2SiW10O36Cu 2(μ-1,1-N3)2] (I, TBA = tetra-n- butylammonium) could act as an efficient reusable homogeneous catalyst for the aerobic oxidative alkyne homocoupling. Various kinds of structurally diverse terminal alkynes including aromatic, heteroaromatic, aliphatic, double bond-containing, silylacetylene, propargylic alcohol, and propargylic amine derivatives could selectively be converted into the corresponding diynes in the presence of I. The catalytic activity of I was much higher than those of the mono-copper-substituted silicotungstate, monomeric copper complexes, and simple copper salts, showing that the di-copper core in I plays an important role in the present alkyne homocoupling. The reaction mechanism involving the formation of the di-copper(II)-alkynyl intermediate, reductive elimination of a diyne, and re-oxidation of reduced copper species by O2 has been proposed.
- Mizuno, Noritaka,Kamata, Keigo,Nakagawa, Yoshinao,Oishi, Takamichi,Yamaguchi, Kazuya
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experimental part
p. 359 - 363
(2011/01/04)
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- Heterogeneously catalyzed efficient alkyne-alkyne homocoupling by supported copper hydroxide on titanium oxide
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The role of the supported Copper Hydroxide on Titanium Oxide as an efficient heterogeneous catalyst for the oxidative alkyne-alkyne homocoupling was analyzed. The catalytic activities for the homocoupling of ethynylbenzene to 1,4-diphenyl-1,3-butadiyne were compared with various catalysts in toluene under oxygen atmosphere. No homocoupling reaction proceeded with bulk copper oxides and hydroxide. The inductively coupled plasma atomic emission spectroscopy analysis revealed that no copper species was found in the filtrate. Therefore, the role of the copper hydroxide species is probably the abstraction of an alkyne hydrogen to form the alkynyl species. The supported copper hydroxide could act as an efficient heterogenous catalyst for the oxidative alkyne-alkyne homocoupling.
- Oishi, Takamichi,Katayama, Tatsuyori,Yamaguchi, Kazuya,Mizuno, Noritaka
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experimental part
p. 7539 - 7542
(2010/03/02)
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- Synthesis and structural characterization of a monomeric di-copper-substituted silicotungstate [γ-H2SiW10O36Cu2(μ-1,1-N3)2]4- and the catalysis of oxidative homocoupling of alkynes
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The di-copper-substituted γ-Keggin silicotungstate with bis-μ-1,1-azido ligands TBA4[γ-H2SiW10O36Cu2(μ-1,1-N3)2] (1, TBA = tetra-n-butylammonium) was synthesized in an aqueous medium. The crystal structure of the anion part of 1 was a monomer of the basal-basal end-on diazido-bridged di-copper-substituted γ-Keggin silicotungstate. The NMR and CSI-MS spectra of 1 in organic solvents, such as acetonitrile, benzonitrile, and 1,2-dichloroethane, showed that complex 1 was present as a monomer of the di-copper-substituted γ-Keggin silicotungstate. Complex 1 could act as an effective homogeneous catalyst for the oxidative homocoupling of various types of alkynes, including aromatic, aliphatic, and heteroatom-containing ones. The reaction possibly proceeds as follows: First, the ligand exchange proceeds between the azido groups in 1 and alkynyl groups to form the corresponding diyne with the reduced copper(I) species via the di-copper(II)-alkynyl intermediate, then the reduced species is reoxidized by molecular oxygen, and the oxidized species reacts with an alkyne to regenerate the alkynyl intermediate.
- Yamaguchi, Kazuya,Kamata, Keigo,Yamaguchi, Syuhei,Kotani, Miyuki,Mizuno, Noritaka
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scheme or table
p. 121 - 130
(2009/02/08)
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- New irreversible thermochromic polydiacetylenes
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New diacetylenic compounds are described. These compounds are unfunctionalised, monoalcohols, diols or monoesters and present irreversible thermochromic behaviour. When heated, these diynes change colour from blue to red in temperature ranging between -50 and +75 °C depending on chain lengths. A relationship between the number of atoms and the thermochromism temperature has been highlighted. Moreover, a mechanism of this thermochromic phenomenon is demonstrated based on Raman spectroscopy, ESR and solid NMR.
- Rougeau, Laurent,Picq, Dominique,Rastello, Marie,Frantz, Yves
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p. 9430 - 9436
(2008/12/22)
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- Synthesis of high specific activity tritium-labelled dotriacontane
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The tobacco smoke particulate phase marker dotriacontane was labelled with tritium at positions 15, 16, 17 and 18 by the catalytic reduction of dotriaconta-15, 17-diyne. This was obtained by oxidatively coupling hexadec-1-yne, in turn prepared by reaction of monosodium acetylide with myristyl bromide.
- Houseman,Binns,Phillips
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p. 163 - 167
(2007/10/05)
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