†Department of Chemistry, Columbia University, New York, New York 10027, United States.
‡The Education Ministry Key Lab of Resource Chemistry, Shanghai Key Laboratory of Rare Earth Functional Materials, Optoelectronic Nano Materials and Devices Institute, Department of Chemistry, Shanghai Normal University, Shanghai, China 200234.
J Am Chem Soc. 2015 Aug 12;137(31):9982-7. doi: 10.1021/jacs.5b05698. Epub 2015 Jul 30.
We present here a new design motif for strained, conjugated macrocycles that incorporates two different aromatics into the cycle with an -A-B-A-B- pattern. In this study, we demonstrate the concept by alternating electron donors and acceptors in a conjugated cycle. The donor is a bithiophene, and the acceptor is a perylene diimide derivative. The macrocycle formed has a persistent elliptiform cavity that is lined with the sulfur atoms of the thiophenes and the π-faces of the perylene diimide. Due to the linkage of the perylene diimide subunits, the macrocycles exist in both chiral and achiral forms. We separate the three stereoisomers using chiral high-performance liquid chromatography and study their interconversion. The mechanism for interconversion involves an "intramolecular somersault" in which one of the PDIs rotates around its transverse axis, thereby moving one of its diimide heads through the plane of the cavity. These unusual macrocycles are black in color with an absorption spectrum that spans the visible range. Density functional theory calculations reveal a photoinduced electron transfer from the bithiophene to the perylene diimide.
我们在这里提出了一种新的应变共轭大环设计基序，该基序采用 -A-B-A-B- 模式将两种不同的芳烃纳入环中。在这项研究中，我们通过在共轭环中交替电子供体和受体来证明这一概念。供体是双噻吩，受体是苝二酰亚胺衍生物。形成的大环具有持久的椭圆形空腔，由噻吩的硫原子和苝二酰亚胺的π面排列。由于苝二酰亚胺亚基的连接，大环存在手性和非手性两种形式。我们使用手性高效液相色谱法分离这三种立体异构体，并研究它们的互变。互变的机制涉及“分子内翻滚”，其中一个 PDIs 绕其横轴旋转，从而使其中一个二酰亚胺头穿过腔的平面。这些不寻常的大环为黑色，具有覆盖可见范围的吸收光谱。密度泛函理论计算表明，从双噻吩到苝二酰亚胺发生光致电子转移。
