Influence of linking alkyl chain length on photoinduced intramolecular electron transfer in bipyridine-linked porphyrin-RuO sub 2 clusters

Journal Article · Thu Aug 08 04:00:00 EDT 1991 · Journal of Physical Chemistry; (United States)

DOI:https://doi.org/10.1021/j100169a023· OSTI ID:7273603

Resch, U; Fox, M A ^[1]

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1. Univ. of Texas, Austin (United States)

In a series of covalently linked meso-tris(octyloxyphenyl)porphyrin-RuO{sub 2} composite clusters, the efficiency of photoinduced intramolecular electron transfer from the porphyrin to the covalently attached RuO{sub 2} cluster depends on the length of the alkyl chain separating the surfactant-like porphyrin from the bipyridine ligating site. The broadening of the porphyrin Soret band and the observation of two distinct triplet-state lifetimes upon complexation to RuO{sub 2} is complexed to the porphyrin {pi} = electron system and (2) a family of more extended (noncomplexed) conformers. The complexed conformers exhibit broadened absorption spectra, decreased fluorescence quantum yields, and diminished triplet-state lifetimes compared to the noncomplexed conformers. Axial ligation of the zinc porphyrin to pyridine reduces intramolecular complexation between the porphyrin {pi}-electron system and the RuO{sub 2} cluster in ZnPB{sub n}R, resulting in unperturbed (narrow) absorption spectra, diminished fluorescence quenching, and a strong diminution of the relative amplitude of the short-lived porphyrin triplet state. However, even in pyridine, the fluorescence intensities, triplet yields, and singlet-state lifetimes of ZnPB{sub n}R are strongly decreased relative to the unbound porphyrin, whereas the porphyrin triplet-state lifetime is unaffected, suggesting intramolecular electron transfer as a major decay route of the porphyrin excited singlet state in the noncomplexed conformers.

• OSTI ID: 7273603
• Journal Information: Journal of Physical Chemistry; (United States), Journal Name: Journal of Physical Chemistry; (United States) Vol. 95:16; ISSN 0022-3654; ISSN JPCHA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400500* -- Photochemistry
AZINES
BIPYRIDINES
CARBOXYLIC ACIDS
CHALCOGENIDES
CHEMICAL REACTIONS
COMPLEXES
DATA
ELECTRON TRANSFER
EXPERIMENTAL DATA
HETEROCYCLIC ACIDS
HETEROCYCLIC COMPOUNDS
INFORMATION
MOLECULAR STRUCTURE
NUMERICAL DATA
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PHOTOCHEMICAL REACTIONS
PORPHYRINS
PYRIDINES
REFRACTORY METAL COMPOUNDS
RUTHENIUM COMPLEXES
RUTHENIUM COMPOUNDS
RUTHENIUM OXIDES
TRANSITION ELEMENT COMPLEXES
TRANSITION ELEMENT COMPOUNDS