52
J. Setsune
Fig. 3.3 Synthesis of square-shaped porphyrin oligomers
Fig. 3.4 Direct synthesis of A 3 B-type meso-tetraarylporphyrin and its application to diporphyrin
et al. 1998). Their molecular design of the diporphyrin chiral sensor was modified
by Borhan and coworkers. The mixed condensation of pentafluorobenzaldehyde,
4-carbomethoxybenzaldehyde, and pyrrole in the molar ratio of 3:1:4 according to
Lindsey’s protocol afforded 19% yield of A 3 B-type porphyrin 8 after chromatographic separation of a mixture of porphyrin products with statistical distribution
of meso-aryl substitution pattern (Fig. 3.4) (Li et al. 2008). 8 was converted to Zn
porphyrin dimer 9Zn 2 which was used for chirality sensing of optically active guest
molecules such as diamines, aminoalcohols, and dialcohols. meso-Pentafluorophenyl
groups increased Lewis acidity of Zn(II) and the guest binding was dependent on
the chain length of the linker. Binding of the asymmetric guest molecules to 9Zn 2
induces face-to-face orientation of two porphyrin rings with their electronic transition
J. Setsune
Fig. 3.3 Synthesis of square-shaped porphyrin oligomers
Fig. 3.4 Direct synthesis of A 3 B-type meso-tetraarylporphyrin and its application to diporphyrin
et al. 1998). Their molecular design of the diporphyrin chiral sensor was modified
by Borhan and coworkers. The mixed condensation of pentafluorobenzaldehyde,
4-carbomethoxybenzaldehyde, and pyrrole in the molar ratio of 3:1:4 according to
Lindsey’s protocol afforded 19% yield of A 3 B-type porphyrin 8 after chromatographic separation of a mixture of porphyrin products with statistical distribution
of meso-aryl substitution pattern (Fig. 3.4) (Li et al. 2008). 8 was converted to Zn
porphyrin dimer 9Zn 2 which was used for chirality sensing of optically active guest
molecules such as diamines, aminoalcohols, and dialcohols. meso-Pentafluorophenyl
groups increased Lewis acidity of Zn(II) and the guest binding was dependent on
the chain length of the linker. Binding of the asymmetric guest molecules to 9Zn 2
induces face-to-face orientation of two porphyrin rings with their electronic transition