title: Synthesis and Properties of Endohedral Aza[60]fullerenes: H₂O@C₅₉N and H₂@C₅₉N as Their Dimers and Monomers.
abstract: The macroscopic-scale syntheses of the first endohedral aza[60]fullerenes X@C59N (X = H2O, H2) were achieved in two different ways: (1) synthesis from endohedral fullerene H2O@C60 as a starting material and (2) molecular surgical synthesis from a C59N precursor having a considerably small opening. In the neutral state of H2O@C59N, we expected the H-bonding interaction or repulsive N-O interaction between entrapped H2O and a nitrogen atom on the C59N cage. However, an attractive electrostatic N-O interaction was suggested from the results of variable temperature NMR, nuclear magnetic relaxation times (T1, T2), and density functional theory (DFT) calculations. Upon the reaction with acetone via cationic intermediate C59N(+), we found a difference in reaction rates between H2O@C59N and H2@C59N dimers (observed reaction rates: k'(H2O)/k'(H2) = 1.74 ± 0.16). The DFT calculations showed thermal stabilization of C59N(+) by entrapped H2O through the electrostatic interaction.
authors.affiliation: Institute for Chemical Research, Kyoto University , Uji, Kyoto 611-0011, Japan.
authors.forename: Yoshifumi
authors.initials: Y
authors.lastname: Hashikawa
authors.affiliation: Institute for Chemical Research, Kyoto University , Uji, Kyoto 611-0011, Japan.
authors.forename: Michihisa
authors.initials: M
authors.lastname: Murata
authors.affiliation: Institute for Chemical Research, Kyoto University , Uji, Kyoto 611-0011, Japan.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Wakamiya
authors.affiliation: Institute for Chemical Research, Kyoto University , Uji, Kyoto 611-0011, Japan.|JST, PRESTO, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan.
authors.forename: Yasujiro
authors.initials: Y
authors.lastname: Murata