Methyl Methacrylate Copolymer with Pendant Thioxanthenone Groups as Active Layer for Resistive Memory Devices

An electro-active copolymer of methyl methacrylate and 2-((4-acroylpiperazine-1-yl)methyl)-9H-thioxanthene-9-one (poly(MMA-co-ThS)) was synthesized by radical polymerization. The copolymer has good solubility in most organic solvents, thermal stability up to 282 °C and excellent ability to form thin films on silicon wafers. Poly(MMA-co-ThS) films exhibited an electrochemical and electrochromic activity resulting in the formation of long-lived radical anion states of pendant thioxanthone groups inside the film. These states exhibit optical transitions in the visible region as a broad optical absorption band, 500<λ<900 nm (1.38 Collapse

Key Words

• Charge transport
• Memristor
• Organic polymers
• Pendant groups
• Spectroelectrochemistry

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MESH Headings Collapse

Grants

• 22-13-00108 Russian Science Foundation
• 3616/6-2 Deutsche Forschungsgemeinschaft

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Affiliation(s)

Danila S Odintsov Novosibirsk Institute of Organic Chemistry, Siberian Branch of the Russian Academy of Sciences, 630090, Novosibirsk, Russian Federation
Andrei A Gismatulin Novosibirsk Institute of Organic Chemistry, Siberian Branch of the Russian Academy of Sciences, 630090, Novosibirsk, Russian Federation
Inna K Shundrina Novosibirsk Institute of Organic Chemistry, Siberian Branch of the Russian Academy of Sciences, 630090, Novosibirsk, Russian Federation
Alexandra D Buktoyarova Novosibirsk Institute of Organic Chemistry, Siberian Branch of the Russian Academy of Sciences, 630090, Novosibirsk, Russian Federation
Irina A Os'kina Novosibirsk Institute of Organic Chemistry, Siberian Branch of the Russian Academy of Sciences, 630090, Novosibirsk, Russian Federation
Jens Beckmann Institute for Inorganic Chemistry and Crystallography, University of Bremen, 28359, Bremen, Germany
Ivan A Azarov Novosibirsk State University, 630090, Novosibirsk, Russian Federation
Ekaterina V Dementeva 194021, Saint Petersburg, Russian Federation
Leonid A Shundrin Novosibirsk Institute of Organic Chemistry, Siberian Branch of the Russian Academy of Sciences, 630090, Novosibirsk, Russian Federation
Vladimir A Gritsenko Novosibirsk Institute of Organic Chemistry, Siberian Branch of the Russian Academy of Sciences, 630090, Novosibirsk, Russian Federation Novosibirsk State Technical University, 630073, Novosibirsk, Russian Federation

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Tuning Molecular Electron Affinities against Atomic Electronegativities by Spatial Expansion of a π-System

2,1,3-Benzochalcogenadiazoles C₆ R₄ N₂ E (E/R; E=S, Se, Te; R=H, F, Cl, Br, I) and C₆ H₂ R₂ N₂ E (E/R'; E=S, Se, Te; R=Br, I) are 10π-electron hetarenes. By CV/EPR measurements, DFT calculations, and QTAIM and ELI-D analyses, it is shown that their molecular electron affinities (EAs) increase with decreasing Allen electronegativities and electron affinities of the E and non-hydrogen R (except Cl) atoms. DFT calculations for E/R+e⋅^- →[E/R]⋅^- electron capture reveal negative ΔG values numerically increasing with increasing atomic numbers of the E and R atoms; positive ΔS has a minor influence. It is suggested that the EA increase is caused by more effective charge/spin delocalization in the radical anions of heavier derivatives due to contributions from diffuse (a real-space expanded) p-AOs of the heavier E and R atoms; and that this counterintuitive effect might be of the general character.

Spectroelectrochemical study of the reduction of 2-methyl-9H-thioxanthene-9-one and its S,S-dioxide and electronic absorption spectra of their molecular ions

2-Methyl-9H-thioxanthene-9-one (1) and its S,S-dioxide (2) are the precursors of pendant groups that determine the reduction potentials of electro-active polyimides, which exhibit electrochromic behavior and are used in organic electronics. Electrochemical reduction of 1 and 2 leads to the formation of the corresponding persistent radical anions and dianion (for S,S-dioxide). Using 3D spectroelectrochemistry, all anions have been shown to exhibit strong absorption in the UV-VIS-NIR wavelength region. Electronic absorption spectra of 1 and 2 and their negative ions were interpreted using time-dependent DFT. According to the calculations, the most intense electronic transitions of the dianions 12- and 22- in the visible region exhibit hypsochromic shift compared to the intense transitions of the corresponding radical anions and have much higher oscillator strengths, which was confirmed experimentally for 2. An empirical kinetic model was proposed based on the analysis of the total charge passed through the cell during electrolysis and on the established mechanism of electrochemical reduction. This model perfectly described the UV-VIS-NIR optical density time dependences observed on 3D spectroelectrochemical surfaces for both compounds 1 and 2. This made it possible to explain the differences in the electrochromic behaviour of ambibolar electro-active polyimides with pendant groups based on 1, 2.

Novel poly(imide-ether)s based on xanthene and a corresponding composite reinforced with a GO grafted hyperbranched polymer: fabrication, characterization, and thermal, photophysical, antibacterial and chromium adsorption properties

High-performance polyimides (PIs) with ether linkages and trifluoromethyl (–CF₃) groups based on xanthene were designed and synthesized via a polycondensation reaction of novel diamine monomers with available aromatic dianhydrides.