Initiating Electron Transfer in Doubly Curved Nanographene Upon Supramolecular Complexation of C₆₀

Abstract

The formation of supramolecular complexes between C 60 and am olecular nanographene endowed with both positive and negative curvatures is described. The presence of ac orannulene moiety and the saddle shape of the molecular nanographene allows the formation of complexes with 1:1, 1:2, and 2:1stoichiometries.The association constants for the three possible supramolecular complexes were determined by 1 HNMR titration. Furthermore,t he stability of the three complexes was calculated by theoretical methods that also predict the photoinduced electron transfer from the curved nanographene to the electron acceptor C 60 .T ime-resolved transient absorption measurements on the ns-time scale showed that the addition of C 60 to NG-1 solutions and photo-exciting them at 460 nm leads to the solvent-dependent formation of new species,i np articular the formation of the one-electron reduced form of C 60 in benzonitrile was observed.

Photoinduced electron transfer in host–guest complexes of double nanohoops

“…Interaction scheme [a] Energy terms [b] , kcal/mol The relationship between nanohoop size and the interaction energy found for the mono adduct is also valid for Twin1 ⊃ 2C 60 , Twin2 ⊃ 2C 60 , and Twin3 ⊃ 2C 60 . The formation energy of the ternary complexes can be expected to be superadditive due to the additional interactions between two fullerenes, similar to that observed in the complexes of fullerenes with other curved carbon nanostructures [70,71]. However, the distance between fullerenes in these complexes is too large (13.590 Å, 27.047 Å, and 26.694 Å for Twin1 ⊃ 2C 60 , Twin2 ⊃ 2C 60 , and Twin3 ⊃ 2C 60 ) for such interactions (Fig.…”