Hashikawa Yoshifumi, Sadai Shumpei, Okamoto Shu, Murata Yasujiro
Institute for Chemical Research, Kyoto University, Uji, Kyoto, 611-0011, Japan.
Angew Chem Int Ed Engl. 2023 Jan 9;62(2):e202215380. doi: 10.1002/anie.202215380. Epub 2022 Dec 2.
Though [60]fullerene is an achiral molecular nanocarbon with I symmetry, it could attain an inherent chirality depending upon a functionalization pattern. The conventional chiral induction of C relies mainly upon a multiple addition affording a mixture of achiral and chiral isomers while their chiral function would be largely offset by the existence of pseudo-mirror plane(s). These are major obstacles to proceed further study on fullerene chirality and yet leave its understanding elusive. Herein, we showcase a carbene-mediated synthesis of C -symmetric chiral open [60]fullerenes showing an intense far-red to near-infrared absorption. The large dissymmetry factor of |g |=0.12 was achieved at λ=820 nm for circular dichroism in benzonitrile. This is, in general, unachievable by other small chiral organic molecules, demonstrating the potential usage of open [60]fullerenes as novel types of chiral chromophores.
尽管[60]富勒烯是具有I对称性的非手性分子纳米碳，但根据官能团化模式，它可以获得固有手性。传统的C的手性诱导主要依赖于多次加成，从而得到非手性和手性异构体的混合物，而它们的手性功能会在很大程度上被伪镜面的存在所抵消。这些是进一步研究富勒烯手性的主要障碍，并且使其理解仍然难以捉摸。在此，我们展示了一种卡宾介导的C对称手性开放[60]富勒烯的合成方法，该富勒烯显示出强烈的远红到近红外吸收。在苯甲腈中，对于圆二色性，在λ=820 nm处实现了|g |=0.12的大不对称因子。一般来说，其他小手性有机分子无法达到这一点，这证明了开放[60]富勒烯作为新型手性发色团的潜在用途。
