Photophysical Characterization of the Naturally Occurring Dioxobacteriochlorin Tolyporphin A and Synthetic Oxobacteriochlorin Analogues
- Department of Chemistry Washington University St. Louis MO
- Photosynthetic Antenna Research Center Washington University St. Louis MO
- Department of Chemistry North Carolina State University Raleigh NC
- Department of Chemistry University of Hawaii at Manoa Honolulu HI
- Department of Plant and Microbial Biology North Carolina State University Raleigh NC
- Department of Chemistry University of California Riverside CA
Tolyporphins are tetrapyrrole macrocycles produced by a cyanobacterium‐containing culture known as HT ‐58‐2. Tolyporphins A–J are free base dioxobacteriochlorins, whereas tolyporphin K is an oxochlorin. Here, the photophysical characterization is reported of tolyporphin A and two synthetic analogues, an oxobacteriochlorin and a dioxobacteriochlorin. The characterization (in toluene, diethyl ether, ethyl acetate, dichloromethane, 1‐pentanol, 2‐butanone, ethanol, methanol, N,N ‐dimethylformamide and dimethylsulfoxide) includes static absorption and fluorescence spectra, fluorescence quantum yields and time‐resolved data. The data afford the lifetime of the lowest singlet excited state and the yields of the nonradiative decay pathways (intersystem crossing and internal conversion). The three macrocycles exhibit only modest variation in spectroscopic and excited‐state photophysical parameters across the solvents. The long‐wavelength (Q y ) absorption band of tolyporphin A appears at ~680 nm and is remarkably narrow (full‐width‐at‐half‐maximum ~7 nm). The position of the long‐wavelength (Q y ) absorption band of tolyporphin A (~680 nm) more closely resembles that of chlorophyll a (662 nm) than bacteriochlorophyll a (772 nm). The absorption spectra of tolyporphins B–I, K (which were available in minute quantities) are also reported in methanol; the spectra of B–I closely resemble that of tolyporphin A. Taken together, tolyporphin A generally exhibits spectral and photophysical features resembling those of chlorophyll a .
- Sponsoring Organization:
- USDOE
- Grant/Contract Number:
- SC0001035
- OSTI ID:
- 1392146
- Alternate ID(s):
- OSTI ID: 1388047
- Journal Information:
- Photochemistry and Photobiology, Journal Name: Photochemistry and Photobiology Journal Issue: 5 Vol. 93; ISSN 0031-8655
- Publisher:
- Wiley-BlackwellCopyright Statement
- Country of Publication:
- United Kingdom
- Language:
- English
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