Narrower HOMO-LUMO gap attained by conformational switching through peripheral polyarylation in 1,4,5,8-tetraaza-9,10-anthraquinodimethanes

2,3,6,7,11,11,12,12-Octaphenyl-1,4,5,8-tetraaza-9,10-anthraquinodimethane was prepared as a sterically hindered molecule from 2,3,6,7-tetraphenyl-1,4,5,8-tetraaza-9,10-anthraquinone via bis(dibromomethylene) derivative through the quadruple Suzuki-Miyaura coupling reaction. An X-ray analysis reveale...

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Bibliographic Details
Published in:Tetrahedron 2018-05, Vol.74 (18), p.2239-2244
Main Authors: Suzuki, Takanori, Ishigaki, Yusuke, Sugawara, Kazuma, Umezawa, Yu, Katoono, Ryo, Shimoyama, Atsushi, Manabe, Yoshiyuki, Fukase, Koichi, Fukushima, Takanori
Format: Article
Language:English
Subjects:
Azaaromatics
Crystal structure
DFT calculation
Middle-molecular strategy
Strained molecule
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Summary:2,3,6,7,11,11,12,12-Octaphenyl-1,4,5,8-tetraaza-9,10-anthraquinodimethane was prepared as a sterically hindered molecule from 2,3,6,7-tetraphenyl-1,4,5,8-tetraaza-9,10-anthraquinone via bis(dibromomethylene) derivative through the quadruple Suzuki-Miyaura coupling reaction. An X-ray analysis revealed that steric repulsion is relieved mainly by twisting the exomethylene bonds, which is less common deformation for hindered quinodimethanes. According to the DFT calculations, the folded geometry with bent exomethylene bonds is the metastable conformer, and thus the nitrogen atoms at peri-positons and polyaryl substituents induce novel switching for the preferred geometry of 9,10-anthraquinodimethane skeleton from the common bent form to the twisted form, which causes a decrease in the HOMO-LUMO-gap energy by ca. 1 eV. [Display omitted]
ISSN:0040-4020
1464-5416
DOI:10.1016/j.tet.2018.03.041