Solid-State Pathway Control via Reaction-Directing Heteroatoms: Ordered Pyridazine Nanothreads through Selective Cycloaddition

Dunning, Samuel G.; Zhu, Li; Chen, Bo; Chariton, Stella; Prakapenka, Vitali B.; Somayazulu, Maddury; Strobel, Timothy A.

doi:10.1021/jacs.1c12143

Cited by 26 publications

(42 citation statements)

References 53 publications

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“…Nanothreads were first synthesized from benzene under pressure in diamond anvil cells or Paris–Edinburgh cells, , but the high-pressure solid-state synthesis technique appears to be quite general for unsaturated hydrocarbons. To date, nanothreads have been synthesized from benzene, , pyridine, aniline, thiophene, cubane, furan, azobenzene, , pyridazine, stilbene, and arene/perfluoroarene cocrystals. − It is expected that more polymers of this kind are coming and that sample sizes of certain threads will rapidly expand as synthesis pressures continue to fall.…”

Section: Introductionmentioning

confidence: 99%

Theoretical Studies of Furan and Thiophene Nanothreads: Structures, Cycloaddition Barriers, and Activation Volumes

2022

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This theoretical study examines the formation, structure, and stability of two of the most ordered nanothreads produced yet, those derived from furan and thiophene. The energetic consequences and activation barriers of the first two steps of oligomerization via a Diels–Alder mechanism were examined. The ca. 20 GPa difference in the synthetic pressures (lower for furan) is explainable in terms of the greater loss of aromaticity by the thiophene. The effects of pressure on the reaction profiles, operating through a volume decrease along the reaction coordinate, are illustrated. The interesting option of polymerization proceeding in one or two directions opens up the possibility of polymers with opposing, cumulative dipole moments. The computed activation volumes are consistently more negative for furan, in accordance with the lower onset pressure of furan polymerization. The energetics of three ordered polymer structures were examined. The syn polymer, with all O/S atoms on the same side, if not allowed to distort, is at a high energy relative to the other two due to the O/S lone pair repulsion, understandably greater for S than for O at the 2.8/2.6 Å separation. Set free, the syn isomers curve or arch in two- or three-dimensional (helical) ways, whose energetics are traced in detail. The syn polymer can also stabilize itself by twisting into zig-zag or helical energy minima. The release of strain in a linear thread as the pressure is relaxed to 1 atm, with consequent thread curving, is a likely mechanism for the observed loss of the crystalline order in the polymer as it is returned to ambient pressure.

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Section: Introductionmentioning

confidence: 99%

Theoretical Studies of Furan and Thiophene Nanothreads: Structures, Cycloaddition Barriers, and Activation Volumes

2022

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“…This solid-state polymerization method tends to follow topochemical reaction routes for the precise synthesis of new carbon-based materials with more saturated and dense structures. − The unsaturated groups like alkenyl, , alkynyl, − and aromatic rings − can be activated without catalyst and irreversibly bonded to form high-density carbon materials with covalent-bond chains or networks. For example, 1D polyacetylene, carbon nanothreads, N-doped nanothreads, 2D F-doped graphene have been synthesized by compressing acetylene, benzene, pyridine, aniline, 1,2-diazine, and benzene-hexafluorobenzene cocrystal . Compared to the aromatics, alkynes tend to have higher reactivity and lower reaction pressure thresholds at ambient temperature.…”

Section: Introductionmentioning

confidence: 99%

High-Pressure Synthesis of Highly Conjugated Polymers via Synergistic Polymerization of Phenylpropiolic Acid

Wang

Tang

Yang

et al. 2022

ACS Appl. Polym. Mater.

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The synergistic reaction between alkyne and phenyl groups is a promising pathway for decreasing the reaction pressures of aromatics and enabling scalable high-pressure synthesis of carbon materials via pressure-induced polymerization (PIP). Here by combining theoretical calculations and experimental data, we demonstrate that a simultaneous polymerization of alkynyl and phenyl groups occurred in phenylpropiolic acid (PPA) with the threshold distance d C···C = 3.3 Å, generating an extended structure consisting of sp2 and sp3 carbons. The reaction pressure of phenyl was significantly decreased to ∼5 GPa, which can be applied for large-scale synthesis. The product has a large π-electron conjugated system, resulting in a band gap energy reduced to 1.65 eV and an electrical conductivity increasing to 1.24 × 10–6 S · cm–1. Our research confirmed that conjugated polymers can be synthesized at lower pressures via the high-pressure synergistic reaction route of phenylethynyl compounds and can be used to further realize applications in organic photovoltaic devices.

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“…Mechanochemically-induced polymerizations wherein pressure causes chemical reactivity can direct critical synthetic routes toward macromolecules (e.g., actin) or other polymeric architectures such as carbon-based nanothreads. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] Nanothreads are synthesized through pressure-induced unidirectional polymerization of small (usually aromatic) molecules generally at pressures ranging from 15-30 GPa. Elucidation of precise reaction mechanisms toward nanothread production and the consequent control thereof -both to reduce reaction pressure and to access targeted reaction outcomes -remain areas of active and rapid advance.…”

Section: Introductionmentioning

confidence: 99%

Photochemically-Mediated Polymerization of Molecular Furan and Pyridine: Synthesis of Nanothreads at Reduced Pressures

Oburn

Huss

Cox

et al. 2022

Preprint

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Nanothreads are an emerging one-dimensional sp3-hybridized material with high predicted tensile strength and a tunable band gap. They can be synthesized by compressing aromatic, or non-aromatic small molecules under 15-30 GPa of pressure. Recently, new avenues are being sought that reduce the pressure required to afford nanothreads; focus has been placed on the polymerization of molecules with reduced aromaticity, favorable stacking, and/or the use of higher reaction temperatures. Herein, we report the photochemically-mediated polymerization of pyridine and furan aromatic precursors, which achieves nanothread formation at reduced pressures. In the case of pyridine, it was found that a combination of slow compression/decompression with broadband UV light exposure yielded a crystalline product featuring a six-fold diffraction pattern with similar interplanar spacings of previously synthesized pyridine-derived nanothreads at a reduced pressure. When furan is compressed to 8 GPa and exposed to broadband UV light, a crystalline solid is recovered that similarly demonstrates X-ray diffraction with an interplanar spacing akin to that of the high-pressure synthesized furan-derived nanothreads. Our method realizes a 1.9-fold reduction in the maximum pressure required to afford furan-derived nanothreads and a 1.4-fold reduction in pressure required pyridine-derived nanothreads. Density functional theory and multiconfigurational wavefunction-based computations were used to understand the photochemical activation of furan and subsequent cascade thermal cycloadditions. The reduction of the onset pressure is caused by an initial [4+4]-cycloaddition followed by increasingly facile thermal [4+2]-cycloadditions during polymerization. Density functional theory and multiconfigurational wavefunction-based computations were used to understand the photochemical activation of furan and subsequent cascade thermal cycloadditions.

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Solid-State Pathway Control via Reaction-Directing Heteroatoms: Ordered Pyridazine Nanothreads through Selective Cycloaddition

Cited by 26 publications

References 53 publications

Theoretical Studies of Furan and Thiophene Nanothreads: Structures, Cycloaddition Barriers, and Activation Volumes

Theoretical Studies of Furan and Thiophene Nanothreads: Structures, Cycloaddition Barriers, and Activation Volumes

High-Pressure Synthesis of Highly Conjugated Polymers via Synergistic Polymerization of Phenylpropiolic Acid

Photochemically-Mediated Polymerization of Molecular Furan and Pyridine: Synthesis of Nanothreads at Reduced Pressures

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