Research group of organic functional materials have published the paper of “From Saddle-Shaped to Planar Cyclic Oligothienoacenes: Stepped-Cyclization and Their Applications in OFETs” in Org. Lett. (2018, 20, 2181-2185, SCI Q1, IF = 6.579). The first author is Dr. Luli, and the corresponding authors are Prof. Jianwu Shi and Hua Wang.

In our previous work, we have found that the multilithiations of saddle-shaped cyclooctatetrathiophene (COTh, 2) in the presence of n-BuLi displayed an interesting specific selectivity (J. Am. Chem. Soc., 2016, 138(31): 10002-10010). Based on this discovery, a series of cyclic oligothienoacenes (1, 3, and 4) have been successfully synthesized through a stepped-cyclization synthetic strategy from 2 in this work. The molecular configuration transforms from the saddle shape of 2 to the quasi-saddle shape (3b, 3c), then to the quasi-helical shape (4b), and at last to the quasi-plane shape (1, 3a, 4a). Organic field-effect transistors (OFETs) based on 1, 3a, and 4a were fabricated. The field-effect mobilities of 7.5 × 10⁻⁴, 2.6 × 10⁻³, and 6.8 × 10⁻⁴ cm² V⁻¹ s⁻¹ were obtained for 1, 3a, and 4a, respectively. Compounds 3a and 4a can act as air-stable p-type organic semiconductors, while 1 is sensitive to the air.