Synthesis and structural features of thiophene-fused analogues of warped nanographene and quintuple helicene

Hsing-An Lin; Kenta Kato; Yasutomo Segawa; Lawrence T Scott; Kenichiro Itami

doi:10.1039/c8sc04470h

Synthesis and structural features of thiophene-fused analogues of warped nanographene and quintuple helicene

Chem Sci. 2018 Dec 19;10(8):2326-2330. doi: 10.1039/c8sc04470h. eCollection 2019 Feb 28.

Authors

Hsing-An Lin^{1

2}, Kenta Kato², Yasutomo Segawa^{1

2}, Lawrence T Scott³, Kenichiro Itami^{1

2

4}

Affiliations

¹ JST-ERATO , Itami Molecular Nanocarbon Project , Nagoya University , Chikusa , Nagoya , 464-8602 , Japan . Email: Itami@chem.nagoya-u.ac.jp ; Email: ysegawa@nagoya-u.jp.
² Graduate School of Science , Nagoya University , Chikusa , Nagoya , 464-8602 , Japan.
³ Merkert Chemistry Center , Boston College , Chestnut Hill , Massachusetts 02467-3860 , USA.
⁴ Institute of Transformative Bio-Molecules (WPI-ITBM) , Nagoya University , Chikusa , Nagoya , 464-8602 , Japan.

Abstract

Thiophene-fused analogues of warped nanographene (WNG) and quintuple helicene (QH) were synthesized via a three-step π-extension of corannulene. Similar to the synthetic route to WNG, five hexagons and five heptagons were generated by a Scholl reaction of pentakis(thienylphenyl)corannulene to form pentathiaWNG. In contrast, decathiaWNG could not be obtained from pentakis(thienylthienyl)corannulene, and instead decathiaQH was generated from the photocyclization of the precursor. X-ray crystallography of the products revealed their conformations and packing modes in the solid state. The configurational features of decathiaQH were further examined by DFT calculations. The absorption and fluorescence spectra of the sulfur-containing WNG and QH were shifted relative to those of the corresponding sulfur-free analogues.