TY - JOUR
T1 - Control of photoinduced electron transfer in zinc phthalocyanine- perylenediimide dyad and triad by the magnesium ion
AU - Fukuzumi, Shunichi
AU - Ohkubo, Kei
AU - Ortiz, Javier
AU - Gutiérrez, Ana M.
AU - Fernández-Lázaro, Fernando
AU - Sastre-Santos, Ángela
PY - 2008/10/30
Y1 - 2008/10/30
N2 - Photoexcitation of a zinc phthalocyanine-perylenediimide (ZnPc-PDI) dyad and a bis(zinc phthalocyanine)-perylenediimide [(ZnPc)2-PDI] triad results in formation of the triplet excited state of the PDI moiety without the fluorescence emission, whereas addition of Mg2+ ions to the dyad and triad results in formation of long-lived charge-separated (CS) states (ZnPc +-PDI-/Mg2+ and (ZnPc)2 +-PDI-/Mg2+) in which PDI- forms a complex with Mg2+. Formation of the CS states in the presence of Mg2+ was confirmed by appearance of the absorption bands due to ZnPc+ and PDI-/Mg2+ complex in the time-resolved transient absorption spectra of the dyad and triad. The one-electron reduction potential (Ered) of the PDI moiety in the presence of a metal ion is shifted to a positive direction due to the binding of Mg2+ to PDI-, whereas the one-electron oxidation potential of the ZnPc moiety remains the same. The binding of Mg2+ to PDI- was confirmed by the ESR spectrum, which is different from that of PDI- without Mg2+. The energy of the CS state (ZnPc+-PDI-/Mg2+) is determined to be 0.79 eV, which becomes lower that of the triplet excited state (ZnPc-3PDI *: 1.07 eV). This is the reason why the long-lived CS states were attained in the presence of Mg2+ instead of the triplet excited state of the PDI moiety.
AB - Photoexcitation of a zinc phthalocyanine-perylenediimide (ZnPc-PDI) dyad and a bis(zinc phthalocyanine)-perylenediimide [(ZnPc)2-PDI] triad results in formation of the triplet excited state of the PDI moiety without the fluorescence emission, whereas addition of Mg2+ ions to the dyad and triad results in formation of long-lived charge-separated (CS) states (ZnPc +-PDI-/Mg2+ and (ZnPc)2 +-PDI-/Mg2+) in which PDI- forms a complex with Mg2+. Formation of the CS states in the presence of Mg2+ was confirmed by appearance of the absorption bands due to ZnPc+ and PDI-/Mg2+ complex in the time-resolved transient absorption spectra of the dyad and triad. The one-electron reduction potential (Ered) of the PDI moiety in the presence of a metal ion is shifted to a positive direction due to the binding of Mg2+ to PDI-, whereas the one-electron oxidation potential of the ZnPc moiety remains the same. The binding of Mg2+ to PDI- was confirmed by the ESR spectrum, which is different from that of PDI- without Mg2+. The energy of the CS state (ZnPc+-PDI-/Mg2+) is determined to be 0.79 eV, which becomes lower that of the triplet excited state (ZnPc-3PDI *: 1.07 eV). This is the reason why the long-lived CS states were attained in the presence of Mg2+ instead of the triplet excited state of the PDI moiety.
UR - http://www.scopus.com/inward/record.url?scp=56049126474&partnerID=8YFLogxK
U2 - 10.1021/jp805464e
DO - 10.1021/jp805464e
M3 - Article
C2 - 18834094
AN - SCOPUS:56049126474
SN - 1089-5639
VL - 112
SP - 10744
EP - 10752
JO - Journal of Physical Chemistry A
JF - Journal of Physical Chemistry A
IS - 43
ER -