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Synthesis and Properties of Terthiophene and Bithiophene Derivatives Functionalized by BF 2 Chelation: A New Type of Electron Acceptor Based on Quadrupolar Structures
Author(s) -
Ono Katsuhiko,
Nakashima Akihiro,
Tsuji Yujiro,
Kinoshita Takatoshi,
Tomura Masaaki,
Nishida Junichi,
Yamashita Yoshiro
Publication year - 2010
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201001185
Subject(s) - terthiophene , thiophene , acceptor , moiety , crystallography , chelation , electron acceptor , derivative (finance) , chemistry , materials science , photochemistry , stereochemistry , inorganic chemistry , organic chemistry , economics , condensed matter physics , physics , financial economics
Terthiophene and bithiophene derivatives functionalized by BF 2 chelation were synthesized as a new type of electron acceptor, and their properties were compared to those of bifuran and biphenyl derivatives. These new compounds are characterized by quadrupolar structures due to resonance contributors generated by BF 2 chelation. The bithiophene derivative has a strong quadrupolar character compared with the bifuran and biphenyl derivatives because their hydrolytic analyses indicated that the bithiophene moiety has a larger on‐site Coulomb repulsion than the others. The terthiophene derivative has a smaller on‐site Coulomb repulsion than the bithiophene derivative due to the addition of a thiophene spacer. These BF 2 complexes exhibit long‐wavelength absorptions and according to measurements of ionization potentials and absorption edges they have energetically low‐lying HOMOs and LUMOs. The crystal structure of the bithiophene derivative is of the herringbone type, with short F ⋅⋅⋅ S and F ⋅⋅⋅ C contacts affording dense crystal packing. n‐Type semiconducting behaviour was observed in organic field‐effect transistors based on these BF 2 complexes.