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Functionalized 8 nm Long Aryleneethynylene Molecular Wire with Alkyne Termini
Author(s) -
Zeng Xianshun,
Wang Changsheng,
Bryce Martin R.,
Batsanov Andrei S.,
Sirichantaropass Skon,
GarcíaSuárez Víctor M.,
Lambert Colin J.,
Sage Ian
Publication year - 2007
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.200700507
Subject(s) - sonogashira coupling , alkyne , chemistry , intramolecular force , regioselectivity , conjugated system , homo/lumo , trimethylsilyl , molecule , molecular orbital , stereochemistry , medicinal chemistry , palladium , organic chemistry , catalysis , polymer
The synthesis of new conjugated aryleneethynylene derivatives of up to ca. 8 nm molecular length (compound 16 ) with terminal alkyne substituents and 9,9‐dihexylfluorene units in the backbone is described. Key synthetic steps are Pd‐mediated Sonogashira coupling methodology combined with regioselective removal from the terminal alkyne units of 2‐hydroxy‐2‐propyl protecting groups in the presence of trimethylsilyl groups. The structural and electronic properties of 16 were obtained from DFT calculations: the intramolecular terminal C ··· C′ distance in its relaxed conformation was found to be 7.8 nm. The calculated distribution of HOMO and LUMO orbitals and the strong blue fluorescence observed for 16 ( λ max = 420, 443 nm in CHCl 3 solution) are consistent with a highly conjugated penta[(9,9‐dihexyl‐2,7‐fluorenylene)ethynylene] structure. Molecule 16 possesses multifunctionality and is of interest for future molecular electronic device applications.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)