Karas Lucas J, Jalife Said, Viesser Renan V, Soares João V, Haley Michael M, Wu Judy I
Department of Chemistry, University of Houston, Houston, TX 77204, USA.
Department of Chemistry & Biochemistry and the Materials Science Institute, University of Oregon, Eugene, OR 97403-1253, USA.
Angew Chem Int Ed Engl. 2023 Sep 4;62(36):e202307379. doi: 10.1002/anie.202307379. Epub 2023 Jul 31.
Whether tetra-tert-butyl-s-indacene is a symmetric D structure or a bond-alternating C structure remains a standing puzzle. Close agreement between experimental and computed proton chemical shifts based on minima structures optimized at the M06-2X, ωB97X-D, and M11 levels confirm a bond-localized C symmetry, which is consistent with the expected strong antiaromaticity of TtB-s-indacene.
四叔丁基-s-茚并萘究竟是对称的D结构还是键交替的C结构仍是一个长期存在的谜题。基于在M06-2X、ωB97X-D和M11水平优化的极小值结构，实验测得的质子化学位移与计算值之间的高度吻合证实了一种键定域的C对称性，这与预期的TtB-s-茚并萘的强反芳香性相一致。
