TY - JOUR
T1 - Supramolecular triad and pentad composed of zinc-porphyrin(s), oxoporphyrinogen, and fullerene(s)
T2 - Design and electron-transfer studies
AU - Schumacher, Amy Lea
AU - Sandanayaka, Atula S.D.
AU - Hill, Jonathan P.
AU - Ariga, Katsuhiko
AU - Karr, Paul A.
AU - Araki, Yasuyuki
AU - Ito, Osamu
AU - D'Souza, Francis
PY - 2007
Y1 - 2007
N2 - By adopting a "covalent-co-ordinate" bonding approach, novel supramolecular pentad and triad molecules composed of zinc-porphyrin(s), fullerene(s), and oxoporphyrinogen redox-/photoactive entities have been constructed, and also characterized by means of spectral and electrochemical techniques. The geometry and electronic structures of the pentad and the triad were deduced by means of DFT calculations. Free-energy calculations suggested that the photoinduced electron/energy transfer from the zinc-porphyrin (ZnP) singlet-excited state to the imidazole modified fullerene (ImC60) acceptor and oxoporphyrinogen (OxP) entities is feasible for both the triad and the pentad. The charge-separation rates (kCS) determined from picosecond time-resolved emission studies were higher for pentad (C 60Im:ZnP)2-OxP than for the corresponding triad. C 6()Im:ZnP-OxP. A comparison of the kCS values previously reported for the covalently linked bis-(zinc-porphyrin)-oxoporphyrinogen triad suggests that employing a fullerene acceptor improves the electron-transfer rates. Nanosecond transient absorption studies provide evidence for the occurrence of electron-transfer processes. Lifetimes of the radical ion pairs (τRIP) are in the range of hundreds of nanoseconds, which indicates that there is charge stabilization in the supramolecular systems.
AB - By adopting a "covalent-co-ordinate" bonding approach, novel supramolecular pentad and triad molecules composed of zinc-porphyrin(s), fullerene(s), and oxoporphyrinogen redox-/photoactive entities have been constructed, and also characterized by means of spectral and electrochemical techniques. The geometry and electronic structures of the pentad and the triad were deduced by means of DFT calculations. Free-energy calculations suggested that the photoinduced electron/energy transfer from the zinc-porphyrin (ZnP) singlet-excited state to the imidazole modified fullerene (ImC60) acceptor and oxoporphyrinogen (OxP) entities is feasible for both the triad and the pentad. The charge-separation rates (kCS) determined from picosecond time-resolved emission studies were higher for pentad (C 60Im:ZnP)2-OxP than for the corresponding triad. C 6()Im:ZnP-OxP. A comparison of the kCS values previously reported for the covalently linked bis-(zinc-porphyrin)-oxoporphyrinogen triad suggests that employing a fullerene acceptor improves the electron-transfer rates. Nanosecond transient absorption studies provide evidence for the occurrence of electron-transfer processes. Lifetimes of the radical ion pairs (τRIP) are in the range of hundreds of nanoseconds, which indicates that there is charge stabilization in the supramolecular systems.
KW - Density functional calculations
KW - Electron transfer
KW - Fullerenes
KW - Porphyrinoids supramolecular chemistry
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U2 - 10.1002/chem.200601854
DO - 10.1002/chem.200601854
M3 - Article
C2 - 17385764
AN - SCOPUS:34250308316
VL - 13
SP - 4628
EP - 4635
JO - Chemistry - A European Journal
JF - Chemistry - A European Journal
SN - 0947-6539
IS - 16
ER -