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Synthesis of a Strained Spherical Carbon Nanocage by Regioselective Alkyne Cyclotrimerization
Author(s) -
Hayase Norihiko,
Nogami Juntaro,
Shibata Yu,
Tanaka Ken
Publication year - 2019
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201903422
Subject(s) - nanocages , regioselectivity , rhodium , chemistry , aromatization , alkyne , molecule , cationic polymerization , catalysis , binap , carbon fibers , derivative (finance) , photochemistry , medicinal chemistry , organic chemistry , materials science , enantioselective synthesis , composite number , financial economics , economics , composite material
The smallest spherical carbon nanocage so far, [2.2.2]carbon nanocage, has been synthesized by the cationic rhodium(I)/H 8 ‐binap complex‐catalyzed regioselective intermolecular cyclotrimerization of a cis ‐1‐ethynyl‐4‐arylcyclohexadiene derivative followed by the triple Suzuki–Miyaura cross‐couplings with 1,3,5‐triborylbenzene and reductive aromatization. This cage molecule is highly strained, and its ring strain is between those of [6] and [5]cycloparaphenylenes. A significant red‐shift of an emission maximum was observed, compared with that of known [4.4.4]carbon nanocage. The sequential cyclotrimerizations of a cis ‐1,4‐diethynylcyclohexadiene derivative with the same rhodium(I) catalyst followed by reductive aromatization failed to afford [1.1.1]carbon nanocage; instead, a β‐graph‐shaped cage molecule was generated.