289908-12-9Relevant academic research and scientific papers
N-porphyrinylamino and -amido compounds by addition of an amino or amido nitrogen to a porphyrin meso position
Jayaraj,Gold,Ball,White
, p. 3652 - 3664 (2000)
This report describes the synthesis and characterization of a series of octaethylpcrphyrin derivatives in which the porphyrin π-network is connected to phenyl, 3-fluoranthenyl, or 1-pyrenyl aromatic systems through a meso amino or amido nitrogen. Metal-free bases and zinc(II) and iron(III) complexes have been obtained. These compounds represent the first examples of linkages between porphyrins and extended π-networks through a nitrogen atom directly attached to a porphyrin meso position. 1H NMR studies of the metal-free bases and zinc complexes showed that in the amido-linked adducts, the plane containing the aryl substituent was oriented perpendicular to the plane of the porphyrin. Linkage through the secondary amino nitrogen, however, allowed the aryl plane to rotate toward coplanarity with the porphyrin plane, resulting in conjugation of the highest occupied aryl and porphyrin molecular orbitals through the nitrogen lone pair. In developing routes to the amino-linked compounds, the facile formation of fused azaaryl chlorins via an oxidative intramolecular cycloaddition was observed. An aryl carbon ortho to the meso linkage attacked the β-carbon of an adjacent pyrrole ring, accompanied by 1,2-migration of a pyrrole β-ethyl substituent and a two-electron oxidation of the initially formed macrocycle. The resulting structures are analogous to benzochlorins. The electronic spectra of the metal-free bases are characterized by intense, long-wavelength bands in the visible region. Molecular structures of the chloroferric complexes of the azabenzofluorantheno- and azabenzpyrenoporphyrin macrocycles (derived from fusion of the fluoranthenyl and pyrenyl substituents, respectively) were obtained by X-ray diffraction. The porphyrin moiety in the azabenzofluoranthenoporphyrin adopted a gable structure, with a 22°fold along a diagonal including the pyrrole-ring C4 and C16 α-carbons. By contrast, the azabenzpyrenoporphyrin was virtually planar.
