Robust, high-performance n-type organic semiconductors.

Organic semiconductors (OSCs) are important active materials for the fabrication of next-generation organic-based electronics. However, the development of n-type OSCs lags behind that of p-type OSCs in terms of charge-carrier mobility and environmental stability. This is due to the absence of molecular designs that satisfy the requirements. The present study describes the design and synthesis of n-type OSCs based on challenging molecular features involving a π-electron core containing electronegative N atoms and substituents. The unique π-electron system simultaneously reinforces both electronic and structural interactions. The current n-type OSCs exhibit high electron mobilities with high reliability, atmospheric stability, and robustness against environmental and heat stresses and are superior to other existing n-type OSCs. This molecular design represents a rational strategy for the development of high-end organic-based electronics.

Air-Stable Benzo[ c]thiophene Diimide n-Type π-Electron Core.

In this paper, the molecular design of the first deep-lowest unoccupied molecular orbital (LUMO) level diimide π-electron core, benzo[ c]thiophene diimide (BTDI), as a novel n-type organic semiconductor was determined. An original synthetic sequence was devised to obtain the target cyclohexyl-BTDI (Cy6-BTDI) derivative. Cy6-BTDI demonstrated completely reversible reduction waves and a stable radical anionic state. Favorable brickwork molecular assembly and two-dimensional charge transport properties of Cy6-BTDI were exhibited in the solid state. As a result, air-stable electron mobilities were obtained from the BTDI organic field-effect transistors under ambient conditions.

2,6,10-Tris(dianisylaminium)-3,7,11- tris(hexyloxy)triphenylene: a robust quartet molecule at room temperature.

[reaction: see text] A new triradical molecule, 2,6,10-tris(dianisylaminium)-3,7,11-tris(hexyloxy)triphenylene 1(3+), was synthesized by oxidative trimerization, palladium-catalyzed amination, and subsequent oxidation. It was chemically stable with a half-life > 1 month and displayed the magnetic parameter of S = 3/2 even at room temperature.

Room-temperature high-spin organic single molecule: nanometer-sized and hyperbranched poly[1,2,(4)-phenylenevinyleneanisylaminium].

Poly[1,2,(4)-phenylenevinyleneanisylaminium] 1 was synthesized by one-pot palladium-catalyzed polycondensation of N-(3-bromo-4-vinylphenyl)-N-(4-methoxyphenyl)-N-(4-vinylphenyl)amine 3 and subsequent oxidation with the thianthrene cation radical tetrafluoroborate: compound 1 three-directionally satisfies a non-Kekulé-type pi-conjugation and the ferromagnetic connectivity of the unpaired electrons of the triarylaminium cationic radical. The average molecular weight of the polymer was 4700-5900 (degree of polymerization = 11-14), which gave a single molecular-based and globular-shaped image of ca. 15 nm diameter by atomic and magnetic force microscopies under ambient conditions. The aminium polyradical 1 with a spin concentration (determined by iodometry) of 0.65 spin/unit displayed an average S (spin quantum number) value of 7/2 even at 70 degrees C according to NMR and magnetization measurements.