Effect of axial ligation or π-π-type interactions on photochemical charge stabilization in "two-point" bound supramolecular porphyrin-fullerene conjugates

被引:79
作者
D'Souza, F
Chitta, R
Gadde, S
Zandler, ME
McCarty, AL
Sandanayaka, ASD
Araki, Y
Ito, O
机构
[1] Wichita State Univ, Dept Chem, Wichita, KS 67260 USA
[2] Tohoku Univ, Inst Multidisciplinary Res Adv Mat, Sendai, Miyagi 9808577, Japan
关键词
electron transfer; fullerenes; photochemistry; porphyrinoids; supramolecular chemistry;
D O I
10.1002/chem.200500186
中图分类号
O6 [化学];
学科分类号
0703 ;
摘要
Two types of structurally well-defined, self-assembled zinc porphyrin-fullerene conjugates were formed by "two-point" binding strategies to probe the effect of axial ligation or pi-pi-type interactions on the photochemical charge stabilization in the supramolecular dyads. To achieve this, meso-tetiaphenylporphyrin was functionalized to possess one or four [18]crown-6 moieties at different locations on the porphyrin macrocycle while fullerene was functionalized to possess an alkyl ammonium cation, and a pyridine or phenyl entities. As a result of the crown ether-ammonium cation complexation, and zinc-pyridine coordination or pi-pi-type interactions, stable zinc porphyrin-fullerene conjugates with defined distance and orientation were formed. Evidence for the zinc-pyridine complexation or pi-pi-type interactions was obtained from the spectral and computational studies. Steady-state and time-resolved emission studies revealed efficient quenching of the zinc-porphyrin singlet excited state in these dyads, and the measured rates of charge separation, k(CS) were found to be slightly better in the case of the dyads held by axial coordination and crown ether-cation complexation. Nanosecond transient absorption studies provided evidence for the electron transfer reactions, and these studies also revealed charge stabilization in these dyads. The lifetimes of the radical ion pairs were found to depend upon the type of porphyrins utilized to form the dyads, that is, porphyrin possessing the crown ether moiety at the ortho position of one of the phenyl rings yielded prolonged charge stabilized states. Addition of pyridine to the supramolecular dyads eliminated the zinc-pyridine coordination or pi-pi-type interactions of the "two-point" bound systems due to the formation of a new zinc-pyridine axial bond thus giving a unique opportunity to probe the effect of axial coordination or pi-pi interactions on k(CS) and k(CR). Under these conditions, the measured electron transfer rates revealed faster k(CS) and slower k(CR) as compared to those obtained in the absence of added pyridine. The evaluated lifetimes of the radical ion-pairs were found to be hundreds of nanoseconds and were longer in the presence of pyridine.
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收藏
页码:4416 / 4428
页数:13
相关论文
共 108 条
[1]   Interlocked and intertwined structures and superstructures [J].
Amabilino, DB ;
Stoddart, JF .
CHEMICAL REVIEWS, 1995, 95 (08) :2725-2828
[2]  
[Anonymous], 1995, Angew. Chem
[3]  
[Anonymous], 1988, Photoinduced electron transfer, part D
[4]  
Balzani V, 1998, COORDIN CHEM REV, V171, P3
[5]   Luminescent and redox-active polynuclear transition metal complexes [J].
Balzani, V ;
Juris, A ;
Venturi, M ;
Campagna, S ;
Serroni, S .
CHEMICAL REVIEWS, 1996, 96 (02) :759-833
[6]  
Balzani V., 2001, ELECT TRANSFER CHEM
[7]   A SPECTROPHOTOMETRIC INVESTIGATION OF THE INTERACTION OF IODINE WITH AROMATIC HYDROCARBONS [J].
BENESI, HA ;
HILDEBRAND, JH .
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 1949, 71 (08) :2703-2707
[8]   Electron transfer - From isolated molecules to biomolecules [J].
Bixon, M ;
Jortner, J .
ELECTRON TRANSFER-FROM ISOLATED MOLECULES TO BIOMOLECULES, PT 1, 1999, 106 :35-202
[9]   Rotaxanes as new architectures for photoinduced electron transfer and molecular motions [J].
Blanco, MJ ;
Jiménez, MC ;
Chambron, JC ;
Heitz, V ;
Linke, M ;
Sauvage, JP .
CHEMICAL SOCIETY REVIEWS, 1999, 28 (05) :293-305
[10]   Selective supramolecular porphyrin/fullerene interactions [J].
Boyd, PDW ;
Hodgson, MC ;
Rickard, CEF ;
Oliver, AG ;
Chaker, L ;
Brothers, PJ ;
Bolskar, RD ;
Tham, FS ;
Reed, CA .
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 1999, 121 (45) :10487-10495