Synthesis of Peripherally Annulated Phenanthroporphyrins

Abstract

Synthesis of unusual phenanthroporphyrins was achieved by a stepwise precursor method. Precursor porphyrins fused with aryl-substituted bicyclo[2.2.2]octadiene afforded the corresponding arylbenzoporphyrins (arylBPs) by a retro Diels− Alder reaction. Unusual phenanthroporphyrins were obtained via the intramolecular Scholl reaction of arylBPs. X-ray crystallographic analysis revealed a distorted, helical porphyrin plane. Redshifted absorptions of tetraphenanthroporphyrin are observed at ca. 580 nm for the B band and at 700−900 nm for the Q bands. Analysis of magnetic circular dichroism spectra and timedependent density functional theory calculations was used to explain the optical properties and electronic structures.

Serendipitous Discovery of Conjugated Dipyrromethene-Linked Nitronaphthoporphyrins

“…Fusion of aromatic rings to the porphyrin nucleus gives mixed results and mononaphtho[1,2- b ]porphyrins 1 or related phenanthroporphyrins 2 (Figure ) give only minor bathochromic shifts. However, related structures with additional fusion to meso -carbons give far more profound changes as illustrated by recently described porphyrins 3 and 4 . , …”

“…However, related structures with additional fusion to mesocarbons give far more profound changes as illustrated by recently described porphyrins 3 and 4. 9, 10 In relation to our investigations into porphyrins with β,β′fusion such as 1 and 2, a series of nitronaphthoporphyrins 5, 6, 7 and 8a were targeted for synthesis (Figure 1). 11 The results from this study showed significant differences in the chromophores depending upon the placement of the nitro substituent.…”

Extra-Annulated Chlorophyll Derivatives by Scholl Reaction

“…(1) A β-aromatic substituent was reacted with the neighboring β-aromatic one to give phenanthrene-fused porphyrins . (2) A β-aromatic substituent was intramolecularly reacted with the porphyrin core at the meso -position to afford porphyrins fused with an aromatic ring . (3) An aromatic substituent at the meso -position was reacted with the porphyrin core at the nearby β-position to produce similar aromatic-fused porphyrins as in (2) .…”