Charge transfer in covalently-linked porphyrin-donor complexes from picosecond transient absorption spectroscopy

Journal Article · Thu Sep 02 00:00:00 EDT 1993 · Journal of Physical Chemistry; (United States)

DOI:https://doi.org/10.1021/j100137a021· OSTI ID:5424658

Loppnow, G R; Melamed, D; Hamilton, A D; Spiro, T G ^[1]

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1. Princeton Univ., NJ (United States)

Octaalkyl free base porphyrins have been synthesized with covalently attached electron donors at a single meso position. Singlet-state lifetimes were determined from fluorescence quenching in three solvents and were found to be [le]1.5 ps for the N,N,N[prime],N[prime]-tetramethyl-1,4-phenylenediamine (TMPD) appended complex, 1.3 ns for the phenyl-TMPD-appended complex, and [ge]5 ns for the phenyl-appended, N,N-dimethylaniline (DMA) appended, and DMA-TMPD-appended porphyrin complexes in o-difluorobenzene. Single photon counting measurements and fluorescence quantum yield quenching studies of the phenyl-appended control and phenyl-TMPD charge-transfer complex gave 14 [+-] 3 and 2 [+-] 0.3 ns excited-state lifetimes, respectively. Fluorescence quantum yields of the TMPD and phenyl-TMPD porphyrins were higher in solvents with lower dielectric constants. Picosecond absorption spectroscopy was performed on molecules exhibiting fluorescence quenching to characterize the charge-transfer state and to determine the recombination kinetics. Conclusive evidence of charge transfer was obtained by observing the donor cation absorption at 606 nm for the TMPD and phenyl-TMPD porphyrins. 49 refs., 10 figs., 2 tabs.

• DOE Contract Number: FG02-88ER13876
• OSTI ID: 5424658
• Journal Information: Journal of Physical Chemistry; (United States), Vol. 97:35; ISSN 0022-3654
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
COMPLEXES
ABSORPTION SPECTROSCOPY
ELECTROCHEMISTRY
SYNTHESIS
PORPHYRINS
COMPILED DATA
ELECTRONIC STRUCTURE
FLUORESCENCE
ORGANIC FLUORINE COMPOUNDS
PHOTONS
REACTION KINETICS
BOSONS
CARBOXYLIC ACIDS
CHEMISTRY
DATA
ELEMENTARY PARTICLES
HETEROCYCLIC ACIDS
HETEROCYCLIC COMPOUNDS
INFORMATION
KINETICS
LUMINESCENCE
MASSLESS PARTICLES
NUMERICAL DATA
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
SPECTROSCOPY
400201* - Chemical & Physicochemical Properties
400400 - Electrochemistry
400500 - Photochemistry
400102 - Chemical & Spectral Procedures