Time‐Resolved Spectroscopic Study on Photoinduced Electron‐Transfer Processes in Zn(<scp>II</scp>)porphyrin–Zn(<scp>II</scp>)chlorin–Fullerene Triad

Ha, Jeong Hyon; Cho, Hyun Sun; Kim, Dongho; Lee, Mi Kyung; Kim, Tae Young; Shim, Young Key

doi:10.1002/cphc.200300695

Cited by 12 publications

(2 citation statements)

References 33 publications

(32 reference statements)

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“…During the past few years, the intermolecular interaction of porphyrins and fullerenes has been studied extensively. Due to their potential applications in processes of molecular recognition [6][7][8][9][10][11], photosynthesis [12][13][14][15][16], photovoltaics [17][18][19][20][21][22][23], energy transfer [24][25][26][27][28][29][30][31][32], and electron transfer [33][34][35][36][37][38][39][40][41][42][43][44][45], porphyrin-fullerene complexes have attracted a great deal of attention. Of particular interest is the development of tetraphenylporphyrin-appended silica stationary phases for the chromatographic separation of fullerenes.…”

Section: Introductionmentioning

confidence: 99%

NMR Studies into the Potential Interactions of Fullerene C60 with Tetraphenylporphyrin and Some of Its Derivatives

Obondi¹,

Rodríguez

2010

Advances in Physical Chemistry

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1H NMR relaxation studies were employed to investigate potential interactions between C60 and tetraphenylporphyrin, H2[TPP], and parasubstituted tetraphenylporphyrins, H2[(p-X)4TPP], where X = CN and OCH3 in solution. The substituted porphyrins provided a means by which to investigate the role that electronic effects play in the interaction process. A comparison of the relaxation rates, R1, and correlation times, τC, of the pyrrole and phenyl hydrogens in these complexes, without and with the presence of C60, revealed that the introduction of C60 into solution did not have a noticeable effect on R1 and τC of these protons in H2[TPP], indicating the absence of long-term intermolecular interaction at either of these two sites. A similar analysis of the two protons in the other two substituted tetraphenylporphyrin analogs revealed slower molecular dynamics indicating the presence of intermolecular interactions. Stronger interactions were observed in H2[(p-OCH3)4TPP] indicating that the electron-donating abilities of the -OCH3 group promote the interaction process. Our results indicate that it is very likely that enhanced selectivity in the chemical purifications of fullerenes and metallofullerenes can be achieved by employing tetraphenylporphyrin-silica stationary phases which have been modified with electron-donating groups.

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Section: Introductionmentioning

confidence: 99%

NMR Studies into the Potential Interactions of Fullerene C60 with Tetraphenylporphyrin and Some of Its Derivatives

Obondi¹,

Rodríguez

2010

Advances in Physical Chemistry

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“…), DG CS must be appreciably negative. [33] The negative value for DG CS is obtained if the distance R DA is lesst han 13.9 , whichs uggestst hat the molecule of ZnPyC 60 is not fully stretched. This is consistentw ith the slight redshift and broadening of the absorption spectra described earlier,a nd suggestst he presence of aw eak interaction between the chlorin and fullerene units in ZnPyC 60 .T he lower bound for the energy of the charge-separated state of in ZnPyC 60 is 1.45 eV (E 00 + DG CS ), correspondingt ot he closed conformation, which is slightly highert han the energy of the triplet excited chlorin unit (1.42 eV) estimated from the phosphorescence of ZnPy ( Figure S11i nt he SupportingI nformation).…”

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confidence: 99%

Cyclic Tetramers of Zinc Chlorophylls as a Coupled Light‐Harvesting Antenna–Charge‐Separation System

Shinozaki

Ohkubo

Fukuzumi

et al. 2015

Chemistry A European J

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A coupled light-harvesting antenna-charge-separation system, consisting of self-assembled zinc chlorophyll derivatives that incorporate an electron-accepting unit, is reported. The cyclic tetramers that incorporated an electron acceptor were constructed by the co-assembly of a pyridine-appended zinc chlorophyll derivative, ZnPy, and a zinc chlorophyll derivative further decorated with a fullerene unit, ZnPyC60 . Comprehensive steady-state and time-resolved spectroscopic studies were conducted for the individual tetramers of ZnPy and ZnPyC60 as well as their co-tetramers. Intra-assembly singlet energy transfer was confirmed by singlet-singlet annihilation in the ZnPy tetramer. Electron transfer from the singlet chlorin unit to the fullerene unit was clearly demonstrated by the transient absorption of the fullerene radical anion in the ZnPyC60 tetramer. Finally, with the co-tetramer, a coupled light-harvesting and charge-separation system with practically 100 % quantum efficiency was demonstrated.

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Photoinduced Electron Transfer in Multiporphyrinic Interlocked Structures: The Effect of Copper(I) Coordination in the Central Site

Flamigni¹,

Talarico²,

Chambron³

et al. 2004

Chemistry A European J

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Photoinduced processes have been determined in a [2]catenane containing a zinc(II) porphyrin, a gold(III) porphyrin, and two free phenanthroline binding sites, Zn-Au(+), and in the corresponding copper(I) phenanthroline complex, Zn-Cu(+)-Au(+). In acetonitrile solution Zn-Au(+) is present in two different conformations: an extended one, L, which accounts for 40 % of the total, and a compact one, S. In the L conformation, the electron transfer from the excited state of the Zn porphyrin to the gold-porphyrin unit (k = 1.3x10(9) s(-1)) is followed by a slow recombination (k = 8.3x10(7) s(-1)) to the ground state. The processes in the S conformation cannot be clearly resolved but a charge-separated (CS) state is rapidly formed and decays with a lifetime on the order of fifty picoseconds. In the catenate Zn-Cu(+)-Au(+), the zinc-porphyrin excited state initially transfers energy to the Cu(I)-phenantholine unit, producing a metal-to-ligand charge-transfer (MLCT) excited state localized on the copper complex with a rate k = 1.4x10(9) s(-1). From this excited state the transfer of an electron to the gold-porphyrin unit takes place, producing the CS state Zn-Cu(2+)-Au(.), which decays with a lifetime of 10 ns. The results are discussed in comparison with the closely related [2]rotaxane, in which a further charge shift from the copper center to the zinc-porphyrin unit leads to the fully CS state. Even in the absence of such full charge separation, it is shown that the lifetimes of the CS states are increased by a factor of about 2-2.5 over those of the corresponding rotaxanes.

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Time‐Resolved Spectroscopic Study on Photoinduced Electron‐Transfer Processes in Zn(II)porphyrin–Zn(II)chlorin–Fullerene Triad

Cited by 12 publications

References 33 publications

NMR Studies into the Potential Interactions of Fullerene C60 with Tetraphenylporphyrin and Some of Its Derivatives

NMR Studies into the Potential Interactions of Fullerene C60 with Tetraphenylporphyrin and Some of Its Derivatives

Cyclic Tetramers of Zinc Chlorophylls as a Coupled Light‐Harvesting Antenna–Charge‐Separation System

Photoinduced Electron Transfer in Multiporphyrinic Interlocked Structures: The Effect of Copper(I) Coordination in the Central Site

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