Axle Length Effect on Photoinduced Electron Transfer in Triad Rotaxane with Porphyrin, [60]Fullerene, and Triphenylamine

作者：Sandanayaka Atula S D; Sasabe Hisahiro; Araki Yasuyuki; Kihara Nobuhiro; Furusho Yoshio; Takata Toshikazu^*; Ito Osamu

来源：Journal of Physical Chemistry A, 2010, 114(16): 5242-5250.

DOI：10.1021/jp911177q

Photoinduced multiple electron-transfer processes of a newly synthesized rotaxane with one acceptor and two donors are studied with the time-resolved fluorescence and absorption methods. In this rotaxane, zinc porphyrin (ZnP) with a crown-ether necklace is employed as a photosensitized electron donor; through the crown-ether, a short axle with C(60) and triphenylamine (TPA) at both terminals is penetrating as an electron acceptor and a hole-shift, respectively (abbreviated as (ZnP;C(60)-(A(S))-TPA)(Rot)). The time-resolved fluorescence and transient absorption measurements reveal that the through-space electron-transfer processes take place via the excited states of the ZnP unit to the spatially arranged C(60) moiety, giving the radical ion pair (ZnP(center dot+);C(60)(center dot-)-(A(S))-TPA)(Rot) in polar solvents. Consecutively, (ZnP;C(60)(center dot-)-(A(S))-TPA(center dot+))(Rot) is also generated by the through-space hole-shift between ZnP and TPA, in addition to the through-bond charge separation via the excited state of the C(60) moiety. Both radial ion pairs have lifetimes of 320-420 ns, which are longer than those of the previously reported similar rotaxane with cationic longer axle (150-170 ns).

• 出版日期2010-4-29