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Quantitative Mono‐Formation and Crystallographic Characterization of Pyrazole‐ and Pyrrole‐Ring Fused Derivatives of C 60
Author(s) -
Yang Le,
Shen Wangqiang,
Liu Yangchun,
Hao Debo,
Pan Changwang,
Yu Bing,
Cong Hailin,
Jin Peng,
Lu Xing
Publication year - 2020
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.202000138
Subject(s) - pyrazole , chemistry , pyrrole , steric effects , ring (chemistry) , adduct , moiety , crystallography , stacking , crystallization , crystal structure , furan , intermolecular force , stereochemistry , molecule , organic chemistry
Nitrogen‐heterocyclic fullerene derivatives have received great interest in the past years due to their potential biological activities and optical properties. Herein, we report a quantitative mono‐formation of the pyrazole‐ and pyrrole‐ring fused derivatives of fullerene C 60 , i.e., C 60 (C 13 N 2 H 10 ) ( 3 ) and C 60 (C 9 NH 11 ) ( 4 ), from the respective reactions between C 60 and diphenylnitrilimine ( 1 ) and N ‐benzylazomethine ylide ( 2 ). Single‐crystal X‐ray diffraction (XRD) crystallographic results unambiguously confirm the formation of [6,6]‐closed derivatives ( 3 and 4 ). Interestingly, the intermolecular π–π interactions between the phenyl groups and C 60 spheres are observed in the crystal of 3 , but they are absent from 4 , indicating that the number of the external phenyl groups has an important influence on the stacking pattern of derivatives during crystallization. Electrochemical results show that the reduction potentials of 3 are positively shifted compared with the corresponding values of pristine C 60 , while the reduction potentials of 4 are all cathodically shifted, revealing the redox processes of C 60 can be selectively modulated by changing the structures of the addends. Notably, our theoretical results demonstrate that the quantitative formation of merely one mono‐adduct without any bis‐ or multi‐adducts detected in both reactions is a direct result from the steric hindrance of the existing bulky pyrazole‐ or pyrrole‐ring moiety on the C 60 cage. This work thus presents a quantitative way for the mono‐formation of the pyrrole‐ and pyrazole‐ring fused derivatives of C 60 , which are potentially useful as organic photovoltaic devices and biological reagents.