Über Dihalogen‐diacetylene (zugleich II. Mitteilung über den Ersatz positiven Wasserstoffs durch Halogen)

Straus, Fritz; Kollek, Leo; Hauptmann, Heinrich

doi:10.1002/cber.19300630740

Cited by 40 publications

(9 citation statements)

References 8 publications

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“…The diiodopolyynes also have electron-rich π-systems that promote interesting reactivity, especially rapid electrophilic addition reactions with halogens such as I 2 and Br 2 . − Iodoalkynes react readily with molecular iodine, much like terminal alkynes . In contrast, internal triple bonds, with only alkyl substituents, react slowly or not at all with I 2…”

Section: Diiodopolyynes As Synthetic Precursorsmentioning

confidence: 99%

Exploiting Unsaturated Carbon–Iodine Compounds for the Preparation of Carbon-Rich Materials

2019

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CONSPECTUS: Conjugated carbon-rich materials have drawn much academic and industrial attention in recent years, due to their intriguing electronic and optical properties and potential applications including organic photovoltaics, flexible and wearable electronics, and chemical and biological sensors. Unsaturated carbon−iodine compounds, mainly the derivatives of iodoalkenes and iodoalkynes, are a class of molecules in which iodine atoms are directly connected to unsaturated carbons. These compounds provide unique advantages in the pursuit of carbon-rich materials, largely due to the Lewis acidity of iodine atoms and the lability of the carbon−iodine bonds. The Lewis acidity and electrophilicity of iodine in unsaturated carbon−iodine compounds make them excellent donors of halogen bonding, which is an attractive interaction between the electrophilic halogen atoms and Lewis basic species. Halogen bonding has emerged as a reliable building block in crystal engineering and supramolecular architectures. In this Account, we illustrate examples of the controlled assembly of diiodopolyynes within host−guest cocrystals that contain oxalamide or urea hosts with appropriate Lewis basic end groups and diiodobutadiyne or diiodohexatriyne guests. Halogen bonding interactions between the host and guest result in an ordered alignment of the diiodopolyynes that allows for a solid-state topochemical polymerization. We have used this approach to prepare poly(diiododiacetylene), PIDA, and poly(iodoethynyliododiacetylene), PIEDA, two conjugated polymers composed only of carbon and iodine. In addition, the polarity of the carbon−iodine bond gives unsaturated carbon−iodine compounds an electron-rich π-system, permitting electrophilic addition reactions with molecular halogens. The halogenated products of these additions can then serve as precursors to other conjugated carbon-rich systems. The lability of the carbon−iodine bond, together with the polarizability of iodine and the higher electronegativity of sp-and sp 2hybridized carbons, open up further possibilities in pursuing novel carbon nanomaterials from unsaturated carbon−iodine compounds. For example, we have developed an iterative method for the synthesis of longer symmetric polyynes from shorter diiodopolyynes, using Stille coupling to the iodine-capped polyynes. The iodination/coupling cycle symmetrically lengthens the polyyne chain by two carbon−carbon triple bonds. This method is particularly helpful for preparing polyynes with an odd number of carbon−carbon triple bonds. In addition, the lability of the carbon−iodine bonds of PIDA leads to facile carbonization by pyrolysis or laser irradiation. More strikingly, diiodoalkenes undergo quantitative elimination of iodine in the presence of Lewis bases. This reaction can be used to eliminate iodine at room temperature from PIDA, in which the carbon− iodine bonds are much more easily broken than in the diiodopolyynes, resulting in graphitic carbon materials.

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Section: Diiodopolyynes As Synthetic Precursorsmentioning

confidence: 99%

Exploiting Unsaturated Carbon–Iodine Compounds for the Preparation of Carbon-Rich Materials

2019

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“…Air oxidation of (_+)-2-phenyl-3-butyn-l-ol in the presence of copper(I) halides produces 2,7-diphenyl-3,5-octadiyne-2,7-diol (I) as a mixture of stereoisomers (Strauss, Kollek & Hauptmann, 1930); the meso and racemic forms of (I) were separated by fractional crystallization and crystals of each suitable for X-ray analysis were obtained from benzene. The less-soluble form was identified as meso-(I), while rac-(I) was obtained from the mother liquors; the molecular structures and numbering used are shown in Fig.…”

Section: Mementioning

confidence: 99%

“…Recrystallization from benzene gave the less-soluble diastereomer as colorless needles; m.p. 472-473 K (literature value 465 K; Strauss, Kollek & Hauptmann, 1930). Suitable crystals for X-ray analysis were obtained from the same solvent by slow evaporation.…”

Section: C(21)--c(24)--c(25)mentioning

confidence: 99%

meso- and rac-2,7-diphenyl-3,5-octadiyne-2,7-diol, C20H18O2

Lord¹,

Winter²,

Rath³

1994

Acta Crystallogr C

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“…The physical properties of these quasi-one-dimensional, semiconducting polymers are striking and have been the subject of considerable interest in their own right.l"? 2 9 -3 1 Of these, the work of Strauss etal.2~, 27 and Dunitz and Robinson'" were of particular significance. to these unique materials has been reflected in the numerous reviews that have appeared over the last decade.…”

Section: Introductionmentioning

confidence: 98%

Topochemical Polymerization: Diynes

Bloor

1989

Comprehensive Polymer Science and Supplements

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Über Dihalogen‐diacetylene (zugleich II. Mitteilung über den Ersatz positiven Wasserstoffs durch Halogen)

Cited by 40 publications

References 8 publications

Exploiting Unsaturated Carbon–Iodine Compounds for the Preparation of Carbon-Rich Materials

Exploiting Unsaturated Carbon–Iodine Compounds for the Preparation of Carbon-Rich Materials

meso- and rac-2,7-diphenyl-3,5-octadiyne-2,7-diol, C20H18O2

Topochemical Polymerization: Diynes

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