Structural Studies of Novel Polydiyne Materials

Butera, Raffaella; Grasso, R. P.; Thakur, M.; Lando, J. B.

doi:10.1021/bk-1987-0337.ch003

Cited by 5 publications

(2 citation statements)

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“…Because there coexist PA chains with high HOMO energy and PD chains with low LUMO energy, the HOMO–LUMO gap of NFC becomes small, of which details will be discussed elsewhere. We consider that the situation is responsible for the significantly high conductivity of a bulk polymer derived from shorter alkatetrayne at least partially. Is it possible in the future to provide NFC with a function such as real flat cable in personal computers and peripherals, that is, to transmit different signals through each PA and PD?…”

Section: Discussionmentioning

confidence: 99%

Transformation of Alkatetrayne Monolayers into Nanoflatcables Studied by Ultraviolet Photoelectron Spectroscopy and Metastable Atom Electron Spectroscopy

et al. 2019

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Nanoflatcables (NFCs) are an array of all-trans π-conjugated chains periodically bridged with and maintained at regular intervals by alkyl chains. The prototype NFC containing alternately arranged polydiacetylenes and polyacetylenes is constructed by the photopolymerization of alkatetrayne molecules physisorbed and laid flat on graphite. Ultraviolet photoelectron spectra (UPS) and metastable atom electron spectra (MAES) before and after polymerization are compared with the first-principles calculations to reveal transformation in the electronic structure caused by the drastic recombination of covalent bonds in the extrathin (0.4 nm) films. Unlike related films so far reported, minute features corresponding well to the calculated density of states are observed in the UPS owing to regularity in monomer arrangement and NFC periodicity, and the top of the HOMO (polyacetylene π) band and that of the HOMO − 1 (polydiacetylene π) band are detected distinctly for NFC, giving a threshold ionization potential of 3.6 eV. Changes in the MAES are explained by orbital consanguinity, large dispersions for specific bands, V-shape valley effect for indiscernible NFC π orbitals, and orbital interaction/mixing between the same and different type(s) of chains detectable in the deflated or inflated distributions of pseudo-π orbitals. These findings enable us to make detailed band assignments in the whole C 2p-derived valence region.

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Section: Discussionmentioning

confidence: 99%

Transformation of Alkatetrayne Monolayers into Nanoflatcables Studied by Ultraviolet Photoelectron Spectroscopy and Metastable Atom Electron Spectroscopy

et al. 2019

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“…8 Whitesides and coworkers investigated thermal curing of soluble polydyines. 9 Hay reported that m-diethynylbenzene was polymerized to polydiyne by oxidative coupling polymerization, 7 and the polymers with diacetylene groups have been investigated for thermal and optical curing materials.…”

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Synthesis and Electrical Properties of Poly(1,4-diethynyl-2,5-dibutoxybenzene)

Okawa

Uryu

1990

Polym J

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ABSTRACT:Poly(l ,4-diethynyl-2,5-dibutoxybenzene ), a polymer containing diacetylene group in the main chain, was synthesized by oxidative coupling polymerization. This polymer was confirmed to have relatively high molecular weight and expected to have polydiyne structure without defects. In solid state 13 C NMR spectrum of this polymer, the peaks assigned to phenyl carbons were splitted to doublet because there were any kinds of conformation around the single bonds between triple bonds of diacetylene groups. A DSC curve of the polymer indicated that it was cross-linked at 620 K because of starting of the rotation around the single bond. Although conductivity of the polymer was very low, the polymer exhibited relatively high photoconductivity attributed to the nature of the repeating unit.KEY WORDS Poly(l,4-diethynyl-2,5-dibutoxybenzene) / Conjugated Polymer/ Oxidative Coupling Polymerization/ Solid State CP/MAS 13 C NMR / Solid State Structure / Main Chain Conformation / Thermal Reactivity / Photoconductivity / Diacetylene compounds are attracting increasing attention worldwide. 1 The reason for this interest is that these compounds are polymerized in solid state and afford single crystal polymers. Since the pioneering work of Wegner in late 1960's, 2 there have been many studies on the polymerization process 3 and the physics of quasi-one-dimensional materials. 4 Many kinds of applications were studied, such as conductive materials 5 and nonlinear optical devices 6 by using unique conjugated main chain of the polymers.tributed to the change of the mam chain conformation. 8 Whitesides and coworkers investigated thermal curing of soluble polydyines. 9Hay reported that m-diethynylbenzene was polymerized to polydiyne by oxidative coupling polymerization, 7 and the polymers with diacetylene groups have been investigated for thermal and optical curing materials. Recently, Lando and coworkers reported that poly(l ,8-nonadiyne) which has alkylene spacer exhibited thermochromism and solvatochromism atPolym.

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Polymerization and characterization of nitrile‐terminated diacetylene materials

Grasso

Lando

1989

J. Polym. Sci. A Polym. Chem.

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SynopsisA family of nitrile-terminated diacetylene materials were synthesized. Samples were prepared in various forms and polymerization was performed photochemically and thermally. The resulting materials exhibited low molecular weights and were obtained in low yields. Although the diacetylene group had oligomerized, no evidence was.found in support of -C=Nchain formation. Thermochromism was exhibited by the irradiated 8-nitrile sample and a molecular interpretation of this chromic transition was discussed. Diffraction data implied that strong intermolecular interactions were present between adjacent nitrile groups in the low temperature phase. I t is suggested that stresses are built up during polymerization which cause the low degree of polymerization and yield.

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Structural Studies of Novel Polydiyne Materials

Cited by 5 publications

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Transformation of Alkatetrayne Monolayers into Nanoflatcables Studied by Ultraviolet Photoelectron Spectroscopy and Metastable Atom Electron Spectroscopy

Transformation of Alkatetrayne Monolayers into Nanoflatcables Studied by Ultraviolet Photoelectron Spectroscopy and Metastable Atom Electron Spectroscopy

Synthesis and Electrical Properties of Poly(1,4-diethynyl-2,5-dibutoxybenzene)

Polymerization and characterization of nitrile‐terminated diacetylene materials

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