Stepwise Syntheses of Bisporphyrins, Bischlorins, and Biscorroles, and of Porphyrin−Chlorin and Porphyrin−Corrole Heterodimers

The stepwise syntheses and characterization of a series
of symmetrical and unsymmetrical bisporphyrins,
bischlorins, and biscorroles, and of porphyrin−chlorin and
porphyrin−corrole dyads possessing ethylene, phenyl,
and stilbene linking units are described. The methodology for
synthesis of 10-substituted corroles 2 and their
cobalt
complexes 9 via a,c-biladiene salts
1 was first developed, and then extended to provide
biscorroles (e.g., 4 and 5)
linked through the 10-positions with phenyl linker units. Using a
similar methodology, phenyl-linked corrole−porphyrin dyads 28 and 30 were also prepared.
By way of intermediate phenyl-linked unsymmetrical
bisdipyrromethanes, a completely unsymmetrical heterobimetallic bisporphyrin
system, 45, was synthesized. Low-valent
titanium coupling (McMurry) reactions were used to prepared
stilbene-linked bisdipyrromethanes (e.g., 46)
which
were subsequently transformed into stilbene-linked bisporphyrins (e.g.,
48). McMurry cross-coupling reactions of
porphyrins bearing p-formylphenyl substituents also afforded
an unsymmetrically substituted bisporphyrinylstilbene,
60, as well as the corresponding homodimers 56
and 59. Likewise, McMurry cross-coupling of a
p-formylphenyl-substituted porphyrin, 62, with a formylchlorin,
63, afforded a stilbene-linked bisporphyrin, 64,
a bischlorin, 66, and
a novel porphyrin−chlorin heterodimer, 65. All novel
products were characterized by 1H NMR, UV−vis, and
mass
spectroscopy and elemental analysis. X-ray structural information
was also obtained for the zinc/nickel bisporphyrin
45 and for the bis-nickel porphyrin−chlorin
65.