Dissecting Trichalcogenasumanenes: π‐Bowl to Planar, Invertible Curvature, and Chiral Polycycles

Abstract

The buckybowl trichalcogenasumanenes show cleavage of flanking benzene ring upon oxidation, which leads their dissection by fusing various amidine moieties onto peripheral region. By gradually increasing the ring size of amidine from five- to six- and seven-membered, the molecule engineering results in the [7-5-6]-, [7-6-6]-, and [7-7-6]-fused polycycles. Three systems are distinct in the molecular geometries, packing motifs, and optoelectronic properties. The [7-5-6]-fused case adopts the flat backbone, displays strong emission with the fluorescence quantum yield up to 52.3 %, and undergoes a two-photon absorption process. The [7-6-6]-fused one is of a curvature with molecular geometry inversion, forms a tight stack of curved π-system, shows broad absorption extended to 700 nm, and exhibits the p-type semiconducting behavior with hole mobility of 4.4×10 cm V s . The [7-7-6]-fused one possesses the highly twisted skeleton to show stable chirality, and exhibits red emission in both solution and solid state. The surgery on trichalcogenasumanene is a promising approach to create polycycles with diverse functionalities.

Design, synthesis, and controllable transformation of bowl-shaped heterosumanenes

“…基于硫杂和硒杂素馨烯的氧化开环反应, 我们合 成了具有很强红光发射的共轭稠杂环. 如图13所示, 我们以硫杂/硒杂素馨烯的氧化开环产物15/35为原料, 经过水解、分子内脱水成酸酐, 然后与苯胺和邻苯二 胺之间的酰化、缩合分别合成了酰亚胺类化合物36/ 37 [34] 和[5-7]并环化合物38/39 [41] . 化合物36~39均具有 分子内电荷转移跃迁(intramolecular charge-transfer transition, ICT), 因而能隙比母体化合物5/7更窄.…”

“…化合物36~39均具有 分子内电荷转移跃迁(intramolecular charge-transfer transition, ICT), 因而能隙比母体化合物5/7更窄. 它们 在溶液态均发射红色荧光, 最大发射峰(λ max )为638 nm, 荧光量子产率(Ф F )高达50% [34,41] . 14).…”

Synthetic approaches to bowl-shaped π-conjugated sumanene and its congeners

“…Having the ring-opened products in hands, they were then subjected to the functional group transformation (molecular-surgery-type functionalization) by treating them with NaOH in EtOH/H 2 O (10:1) under reflux conditions to first convert esters functionality into the corresponding carboxylic acid derivatives. As displayed in Scheme 47 , these acid derivatives were then transformed into acid anhydrides which on further treatment with different aromatic amines afforded a variety of polyheterocylic compounds [ 82 , 86 ]. Furthermore, Shao’s group has also assembled the diimide-based heterocycles as depicted in Scheme 48 [ 83 ].…”

Chemistry of Hetera-buckybowl Trichalcogenasumanenes

“…27 Further, amidation and successive condensation of 32/33 with 1,2-diaminobenzene, naphthalene-1,8-diamine, and [1,1′-biphenyl]-2,2′-diamine afforded 36/37, 38/39, and 40/41, respectively. 37 The key difference between 36/37, 38/39, and 40/41 is the size of the amidine ring (highlighted in red), which has a large influence on the molecular geometries, packing motifs, and optoelectronic properties. The crystal structures of representative compounds of this series are shown in Figure 6.…”

“…Products 36 and 37 showed two-photon absorption. 37 Recently, we disclosed a new method toward bowl-shaped polycycles, that is, a coordination-induced plane to -bowl transformation. 44 In this case, both the molecular geometry and photoluminescence are distinctly varied upon coordination, i.e., green and red emission for the planar and bowl-shaped materials, respectively.…”