Ultrafast charge separation in a photoreactive rhenium-appended porphyrin assembly monitored by picosecond transient infrared spectroscopy

被引:103
作者
Gabrielsson, A
Hartl, F
Zhang, H
Smith, JRL
Towrie, M
Vlcek, A
Perutz, RN [1 ]
机构
[1] Univ York, Dept Chem, York YO10 5DD, N Yorkshire, England
[2] Univ Amsterdam, Van Hoff Inst Mol Sci, NL-1018 WV Amsterdam, Netherlands
[3] CCLRC, Cent Laser Facil, Rutherford Appleton Lab, Didcot OX11 0QX, Oxon, England
[4] Univ London Queen Mary Coll, Dept Chem, London E1 4NS, England
关键词
D O I
10.1021/ja0539802
中图分类号
O6 [化学];
学科分类号
0703 ;
摘要
Rhenium(bipyridine)(tricarbonyl)(picoline) units have been linked covalently to tetraphenylmetalloporphyrins of magnesium and zinc via an amide bond between the bipyridine and one phenyl substituent of the porphyrin. The resulting complexes, abbreviated as [Re(CO)(3)(Pic)Bpy-MgTPP][OTf] and [Re(CO)(3)(Pic)Bpy-ZnTPP][OTf], exhibit no signs of electronic interaction between the Re(CO)(3)(bpy) units and the metalloporphyrin units in their ground states. However, emission spectroscopy reveals solvent-dependent quenching of porphyrin emission on irradiation into the long-wavelength absorption bands localized on the porphyrin. The characteristics of the excited states have been probed by picosecond time-resolved absorption (TRVIS) spectroscopy and time-resolved infrared (TRIR) spectroscopy in nitrile solvents. The presence of the charge-separated state involving electron transfer from MgTPP or ZnTPP to Re(bpy) is signaled in the TRIR spectra by a low-frequency shift in the nu(CO) bands of the Re(CO)(3) moiety similar to that observed by spectroelectrochemical reduction. Long-wavelength excitation of [Re(CO)(3)(Pic)Bpy-MTPP][OTf] results in characteristic TRVIS spectra of the S-1 state of the porphyrin that decay with a time constant of 17 ps (M = Mg) or 24 ps (M = Zn). The IR bands of the CS state appear on a time scale of less than 1 ps (Mg) or ca. 5 ps (Zn) and decay giving way to a vibrationally excited (i.e., hot) ground state via back electron transfer. The IR bands of the precursors recover with a time constant of 35 ps (Mg) or 55 ps (Zn). The short lifetimes of the charge-transfer states carry implications for the mechanism of reaction in the presence of triethylamine.
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页码:4253 / 4266
页数:14
相关论文
共 117 条
  • [1] Long-range electron transfer in porphyrin-containing [2]-rotaxanes:: Tuning the rate by metal cation coordination
    Andersson, M
    Linke, M
    Chambron, JC
    Davidsson, J
    Heitz, V
    Hammarström, L
    Sauvage, JP
    [J]. JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 2002, 124 (16) : 4347 - 4362
  • [2] Porphyrin-containing [2]-rotaxanes:: Metal coordination enhanced superexchange electron transfer between noncovalently linked chromophores
    Andersson, M
    Linke, M
    Chambron, JC
    Davidsson, J
    Heitz, V
    Sauvage, JP
    Hammarström, L
    [J]. JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 2000, 122 (14) : 3526 - 3527
  • [3] Systematic synthesis and photochemistry of tetraaryl porphyrins mono-substituted with a transition metal carbonyl: characterisation of a zinc porphyrin-rhenium carbonyl complex
    Aspley, CJ
    Smith, JRL
    Perutz, RN
    [J]. JOURNAL OF THE CHEMICAL SOCIETY-DALTON TRANSACTIONS, 1999, (14): : 2269 - 2271
  • [4] Synthesis and photochemistry of free base and zinc tetraaryl porphyrins mono-substituted with tungsten pentacarbonyl via a pyridine linker
    Aspley, CJ
    Smith, JRL
    Perutz, RN
    Pursche, D
    [J]. JOURNAL OF THE CHEMICAL SOCIETY-DALTON TRANSACTIONS, 2002, (02): : 170 - 180
  • [5] ASPLEY CJ, 2000, THESIS U YORK
  • [6] BALABAN TS, 2004, LIGHT HARVESTING NAN, V4
  • [7] EFFICIENT PERIPHERAL FUNCTIONALIZATION OF PORPHYRINS
    BALDWIN, JE
    CROSSLEY, MJ
    DEBERNARDIS, J
    [J]. TETRAHEDRON, 1982, 38 (05) : 685 - 692
  • [8] Balzani V.S. F., 1991, Supramolecular Photochemistry
  • [9] Intramolecular energy transfer in molecular dyads comprising free-base porphyrin and ruthenium(II) bis(2,2′:6′,2"-terpyridine) termini
    Benniston, AC
    Chapman, GM
    Harriman, A
    Mehrabi, M
    [J]. JOURNAL OF PHYSICAL CHEMISTRY A, 2004, 108 (42) : 9026 - 9036
  • [10] Electron transfer - From isolated molecules to biomolecules
    Bixon, M
    Jortner, J
    [J]. ELECTRON TRANSFER-FROM ISOLATED MOLECULES TO BIOMOLECULES, PT 1, 1999, 106 : 35 - 202