Transient absorption spectroscopy of bacteriochlorophyll a: Cation radical generated in solvents forming aggregates and T[sub 1] species generated in solvents forming penta- and hexacoordinated monomers with and without hydrogen bonding

Journal Article · Thu Nov 17 00:00:00 EST 1994 · Journal of Physical Chemistry; (United States)

DOI:https://doi.org/10.1021/j100097a039· OSTI ID:6620040

Nishizawa, E; Koyama, Y ^[1]; Nagae, H ^[2]

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1. Kwansei Gakuin Univ., Nishinomiya (Japan)
2. Kobe City Univ. of Foreign Studies (Japan)

Transient absorption spectra of bacteriochlorophyll a were recorded at room temperature in 16 different solvents 200 ns after excitation. The cation radical was found in carbon tetrachloride forming higher aggregates, both the cation radical and the T[sub 1] species were found in methylene chloride forming lower aggregates, and the T[sub 1] species was found in the rest of the solvents forming monomers. Thus, the cation radical can be formed in the aggregates upon photoexcitation. The T[sub 1] [yields] T[sub n] absorption spectra exhibited the following solvent effects: (1) In non-hydrogen-bonding solvents, the lowest-energy peak shifted to the lower energies upon transformation from the penta- to hexacoordinated state. (2) In hydrogen-bonding solvents (alcohols), the transformation caused the low-energy shifts of the lower three peaks as well as the appearance of a new split peak. (3) Replacement of a non-hydrogen-bonding solvent by a hydrogen-bonding solvent, in the same state of coordination, also caused the low-energy shifts of the above absorption peaks. 19 refs., 4 figs., 2 tabs.

• OSTI ID: 6620040
• Journal Information: Journal of Physical Chemistry; (United States), Vol. 98:46; ISSN 0022-3654
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
59 BASIC BIOLOGICAL SCIENCES
CHLOROPHYLL
ABSORPTION SPECTROSCOPY
ALCOHOLS
CARBON TETRACHLORIDE
CATIONS
CHEMICAL BONDS
COMPILED DATA
METHYLENE CHLORIDE
MONOMERS
PHOTOSYNTHETIC BACTERIA
RADICALS
SOLVENTS
BACTERIA
CARBOXYLIC ACIDS
CHARGED PARTICLES
CHLORINATED ALIPHATIC HYDROCARBONS
DATA
HALOGENATED ALIPHATIC HYDROCARBONS
HETEROCYCLIC ACIDS
HETEROCYCLIC COMPOUNDS
HYDROXY COMPOUNDS
INFORMATION
IONS
MICROORGANISMS
NUMERICAL DATA
ORGANIC ACIDS
ORGANIC CHLORINE COMPOUNDS
ORGANIC COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PHYTOCHROMES
PIGMENTS
PORPHYRINS
PROTEINS
SPECTROSCOPY
140505* - Solar Energy Conversion- Photochemical
Photobiological
& Thermochemical Conversion- (1980-)
400201 - Chemical & Physicochemical Properties
400500 - Photochemistry
550200 - Biochemistry
400102 - Chemical & Spectral Procedures