Rhodium‐Catalyzed Intermolecular Cycloaromatization Route to Cycloparaphenylenes that Exhibit Aggregation‐Induced Emission

• Published in: Chemistry : a European journal 2022-04, Vol.28 (21), p.e202200064-n/a
• Main Authors: Wang, Li‐Hsiang, Nagashima, Yuki, Abekura, Masato, Uekusa, Hidehiro, Konishi, Gen‐ichi, Tanaka, Ken
• Format: Article
• Language: English
• Subjects: [2+2+2] cycloaddition; Agglomeration; aggregation-induced emission; Chemistry; Cycloaddition; cycloparaphenylene-triphenylenes; cyclophenylene-ethynylenes; Emission; Rhodium; Substitutes
• ISSN: 0947-6539; 1521-3765
• DOI: 10.1002/chem.202200064

A high‐yielding new route to substituted cycloparaphenylenes has been developed via reductive aromatization of a diyne bearing two cyclohexadiene units giving a cyclophenylene‐ethynylene (CPE) followed by the cationic rhodium(I)/dppe complex‐catalyzed intermolecular [2+2+2] cycloaddition (cycloaromatization) of the CPE with monoynes. The thus‐obtained products, substituted [8]cycloparaphenylene‐triphenylenes ([8]CPPTs), exhibited definite aggregation‐induced emission (AIE). This molecule is noteworthy as a novel AIE‐active cycloarylene that does not have well‐known AIE luminogens, such as tetraphenylethene and 1,2,4,5‐tetraphenylbenzene skeletons. The single‐crystal X‐ray diffraction analyses of the AIE‐active [8]CPPTs revealed their highly ordered packing structures in which the rotation of the triphenylene moieties is restricted. We have developed a high‐yielding new route to substituted cycloparaphenylenes via the cationic rhodium(I)‐catalyzed intermolecular [2+2+2] cycloaddition of cyclophenylene‐ethynylenes with monoynes. The thus obtained products, substituted [8]cycloparaphenylene‐triphenylenes, exhibited definite aggregation‐induced emission (AIE), and are noteworthy as a novel AIE‐active cycloarylene that does not have ordinally AIE luminogens, such as tetraphenyl‐ethene and benzene skeletons.