Resonance Raman spectroscopy of a chlorophyll-porphyrin heterodimer. Excitation profile in the 400-450-nm region

Journal Article · Thu Sep 23 00:00:00 EDT 1993 · Journal of Physical Chemistry; (United States)

DOI:https://doi.org/10.1021/j100140a012· OSTI ID:5575997

Gosztola, D; Wasielewski, M R ^[1]

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1. Argonne National Lab., IL (United States)

Photophysical studies carried out previously on a chlorophyll-porphyrin heterodimer consisting of a zinc methyl pyrochlorophyllide a that is directly bonded at its 3-position to the 5-position of a zinc 2,8,12,18- tetraethyl-3,7,13,17-tetramethyl-15-(p-tolyl)porphyrin have shown that the chlorophyll and porphyrin interact within the excited singlet manifold. Steric hindrance between adjacent substituents rigidly positions the [pi] systems of both macrocycles perpendicular to one another. A similar orientation occurs between the primary donor and accessory bacteriochlorophyll in the photosynthetic reaction center. To better understand the relationship between the structure and the electronic states of the chlorophyll-porphyrin heterodimer, we have carried out a series of resonance Raman measurements in the Soret band region of the chlorophyll-porphyrin heterodimer. Our data yield the assignment of the two individual Soret bands in the 400-450-nm region to the chlorophyll and porphyrin macrocycles and allow us to characterize the vibrational frequencies present in the ground electronic state of the heterodimer. 21 refs., 5 figs., 3 tabs.

• DOE Contract Number: W-31109-ENG-38
• OSTI ID: 5575997
• Journal Information: Journal of Physical Chemistry; (United States), Journal Name: Journal of Physical Chemistry; (United States) Vol. 97:38; ISSN JPCHAX; ISSN 0022-3654
• Country of Publication: United States
• Language: English

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59 BASIC BIOLOGICAL SCIENCES
BACTERIA
CARBOXYLIC ACIDS
CHEMICAL REACTIONS
CHLOROPHYLL
DIMERS
ELECTRONIC STRUCTURE
ENERGY LEVELS
EXCITED STATES
HETEROCYCLIC ACIDS
HETEROCYCLIC COMPOUNDS
MICROORGANISMS
MOLECULAR STRUCTURE
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANOMETALLIC COMPOUNDS
PHOTOCHEMICAL REACTIONS
PHOTOSYNTHESIS
PHOTOSYNTHETIC BACTERIA
PHYSICAL PROPERTIES
PHYTOCHROMES
PIGMENTS
PORPHYRINS
PROTEINS
RAMAN SPECTRA
RESONANCE
SPECTRA
SYNTHESIS
VIBRATIONAL STATES
ZINC COMPOUNDS