title: Syntheses, structures, modification, and optical properties of meso-tetraaryl-2,3-dimethoxychlorin, and two isomeric meso-tetraaryl-2,3,12,13-tetrahydroxybacteriochlorins.
abstract: The refined syntheses, modification, and first X-ray structural characterization of meso-tetraarylporphyrin-derived beta-tetraolbacteriochlorins are described. These investigations assign the relative stereochemistry of their two isomers (both cis-vic-diol pairs on the same or opposite sides of the porphyrin plane), an assignment that could not be provided by NMR, UV-vis or fluorescence spectroscopy, or mass spectrometry. Moreover, the first crystal structures of a 2-hydroxychlorin and a 2,3-dihydroxychlorin, as its dimethylether, are reported. Dihydroxylation and diimide reduction of the dimethoxychlorin result in the formation of stable mixed-functionality bacteriochlorins. The photophysical properties (UV-vis absorption and fluorescence emission) of all chromophores are contrasted against each other, delineating the electronic effects of diol substitution and conformational modulation. Lastly, the acid-induced dehydration/demethoxylation of the tetraol-, dioldimethoxy-, and tetramethoxybacteriochlorins to provide chlorins is delineated.
authors.affiliation: Department of Chemistry, University of Connecticut, Unit 3060, Storrs, CT 06269-3060, USA.
authors.forename: Lalith P
authors.initials: LP
authors.lastname: Samankumara
authors.forename: Matthias
authors.initials: M
authors.lastname: Zeller
authors.forename: Jeanette A
authors.initials: JA
authors.lastname: Krause
authors.forename: Christian
authors.initials: C
authors.lastname: Brückner
mesh_terms: D018360:Crystallography, X-Ray; D007536:Isomerism; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D008958:Models, Molecular; D011166:Porphyrins / Q000138:chemical synthesis / Q000737:chemistry*; D011522:Protons; D013050:Spectrometry, Fluorescence; D013056:Spectrophotometry, Ultraviolet
chemical_list: D011166:Porphyrins; D011522:Protons; C452433:bacteriochlorin; C551097:meso-tetraaryl-2,3-dimethoxychlorin; C006969:chlorin