Cyclophane-Type Chlorin Dimers from Dynamic Covalent Chemistry of 2,18-Porphyrinyl Dicyanomethyl Diradicals

被引：12

作者：

Adinarayana, B. ^{[1
]}

Kato, Kenichi ^{[1
]}

Shimizu, Daiki ^{[1
]}

Tanaka, Takayuki ^{[1
]}

Furukawa, Ko ^{[2
,3
]}

Osuka, Atsuhiro ^{[1
]}

机构：

[1] Kyoto Univ, Dept Chem, Grad Sch Sci, Sakyo Ku, Kyoto 6068502, Japan

[2] Niigata Univ, Inst Res Promot, Ctr Coordinat Res Facil, Nishi Ku, Niigata 9502181, Japan

[3] Inst Mol Sci, 38 Nishigo Naka, Okazaki, Aichi 4448585, Japan

来源：

ANGEWANDTE CHEMIE-INTERNATIONAL EDITION | 2020年 / 59卷 / 11期

关键词：

chlorin; cyclophane dimers; dicyanomethyl radical; dynamic covalent bonds; porphyrin; CRYSTAL-STRUCTURE; QUINOIDAL PORPHYRIN; PHOTOSYSTEM-II; BIS(CHLOROPHYLL)CYCLOPHANES; RADICALS; MODELS;

D O I：

10.1002/anie.201914480

中图分类号：

O6 [化学];

学科分类号：

0703 ;

摘要：

2,18-Bis(dicyanomethyl)-substituted Ni-II porphyrin 8 and Zn-II porphyrin 11 were prepared and subjected to oxidation with PbO2 in CH2Cl2 at 298 K to give cyclophane-type chlorin dimers (9)(2) and (12)(2) as a consequence of double recombination of biradicals 9 and 12, respectively. Dimer (9)(2) takes a syn-conformation of two distorted Ni-II chlorins but (12)(2) takes an anti-conformation of relatively planar Zn-II chlorins. At 298 K, dimer (9)(2) is stable and its H-1 NMR spectrum is sharp but becomes broad at high temperature, while the H-1 NMR spectrum of (12)(2) is considerably broad even at 298 K but becomes sharper at low temperature. These results indicate that the chlorin dimers dissociate to radical species, but the activation barrier of the dissociation of (12)(2) is much less than that of (9)(2). The involvement of diradicals in dynamic covalent chemistry has been suggested by thermal scrambling of hetero dimer (16)(2) to give homo dimers (9)(2) and (15)(2).

引用

页码：4320 / 4323

页数：4