Title: Photophysical Characterization of the Naturally Occurring Dioxobacteriochlorin Tolyporphin A and Synthetic Oxobacteriochlorin Analogues

Abstract

Abstract 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 chlorophyllmore » a .« less

Authors:

Hood, Don ^[1]; Niedzwiedzki, Dariusz M. ^[2]; Zhang, Ran ^[3]; Zhang, Yunlong ^[3]; Dai, Jingqiu ^[4]; Miller, Eric S. ^[5]; Bocian, David F. ^[6]; Williams, Philip G. ^[4]; Lindsey, Jonathan S. ^[3]; Holten, Dewey ^[1]

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+ Show Author Affiliations

1. Department of Chemistry Washington University St. Louis MO
2. Photosynthetic Antenna Research Center Washington University St. Louis MO
3. Department of Chemistry North Carolina State University Raleigh NC
4. Department of Chemistry University of Hawaii at Manoa Honolulu HI
5. Department of Plant and Microbial Biology North Carolina State University Raleigh NC
6. Department of Chemistry University of California Riverside CA

Publication Date:

Tue Jul 25 00:00:00 EDT 2017

Sponsoring Org.:

USDOE

OSTI Identifier:

1392146

Resource Type:

Publisher's Accepted Manuscript

Journal Name:

Photochemistry and Photobiology

Additional Journal Information:

Journal Name: Photochemistry and Photobiology Journal Volume: 93 Journal Issue: 5; Journal ID: ISSN 0031-8655

Publisher:

Wiley-Blackwell

Country of Publication:

United Kingdom

Language:

English