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

作者：Suzuki Takanori^*; Ishigaki Yusuke; Sugawara Kazuma; Umezawa Yu; Katoono Ryo; Shimoyama Atsushi; Manabe Yoshiyuki; Fukase Koichi; Fukushima Takanori

来源：Tetrahedron, 2018, 74(18): 2239-2244.

DOI：10.1016/j.tet.2018.03.041

• Azaaromatics
• Strained molecule
• Crystal structure
• DFT calculation
• Middle-molecular strategy

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 OFT 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.

• 出版日期2018-5-3