| Institution: | 1. College of Chemistry and Chemical Engineering, Central South University, 410083 Changsha, China
These authors contributed equally to this work;2. Organic and Carbon Nanomaterials Unit, Okinawa Institute of Science and Technology Graduate University, 1919-1 Tancha, Onna-son, Kunigami-gun, Okinawa, 904-0495 Japan;3. Department of Chemistry and Chemical Engineering, Xiamen University, 361005 Xiamen, China;4. Center of Spectroelectrochemistry, Leibniz Institute for Solid State and Materials Research, Helmholtzstrasse 20, 01069 Dresden, Germany;5. College of Chemistry and Chemical Engineering, Central South University, 410083 Changsha, China;6. MOE Key Laboratory of Macromolecular Synthesis and Functionalization, International Research Center for X Polymers Department of Polymer Science and Engineering, Zhejiang University, 310027 Hangzhou, China |
| Abstract: | A negatively curved aza-nanographene (NG) containing two octagons was synthesized by a regioselective and stepwise cyclodehydrogenation procedure, in which a double aza7]helicene was simultaneously formed as an intermediate. Their saddle-shaped structures with negative curvature were unambiguously confirmed by X-ray crystallography, thereby enabling the exploration of the structure–property relationship by photophysical, electrochemical and conformational studies. Moreover, the assembly of the octagon-embedded aza-NG with fullerenes was probed by fluorescence spectral titration, with record-high binding constants (Ka=9.5×103 M?1 with C60, Ka=3.7×104 M?1 with C70) found among reported negatively curved polycyclic aromatic compounds. The tight association of aza-NG with C60 was further elucidated by X-ray diffraction analysis of their co-crystal, which showed the formation of a 1 : 1 complex with substantial concave-convex interactions. |
