Department of Chemistry, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502 (Japan).
Angew Chem Int Ed Engl. 2014 Apr 22;53(17):4395-8. doi: 10.1002/anie.201400632. Epub 2014 Mar 18.
7,8-Dehydropurpurin has attracted much attention owing to the dual 18π- and 20π-electron circuits in its macrocyclic conjugation. The two-fold Pd-catalyzed [3+2] annulation of meso-bromoporphyrin with 1,4-diphenylbutadiyne furnished 7,8-dehydropurpurin dimers. The 8(a) ,8(a) -linked dimer displays a red-shifted and enhanced absorption band in the NIR region and a small electrochemical HOMO-LUMO band gap as a consequence of efficient conjugation between the two coplanar 7,8-dehydropurpurin units. Treatment of this dimer with N-bromosuccinimide in chloroform and ethanol gave β-to-β vinylene-bridged porphyrin dimers. Owing to the highly constrained conformations, these dimers exhibit perturbed absorption spectra, small Stokes shifts, and high fluorescence quantum yields.
7,8-脱水紫质因其大环共轭中存在双 18π-和 20π-电子电路而引起了广泛关注。间溴卟啉与 1,4-二苯基丁二炔的双钯催化 [3+2] 环加成反应得到了 7,8-脱水紫质二聚体。8(a),8(a)-连接的二聚体由于两个共面的 7,8-脱水紫质单元之间的有效共轭，在近红外区域显示出红移和增强的吸收带，以及较小的电化学 HOMO-LUMO 带隙。用 N-溴代丁二酰亚胺在氯仿和乙醇中处理这个二聚体得到了β-到β-亚乙烯基桥联卟啉二聚体。由于高度受限的构象，这些二聚体表现出扰动的吸收光谱、小的斯托克斯位移和高的荧光量子产率。
