文摘
Two monosubstituted and one tetrasubstituted N-confused porphyrins (1鈥?b>3) were prepared in ca. 3鈥?% yields using a [2 + 2] synthesis. The monosubstituted porphyrins have carbomethoxy (1) or nitro (2) substituents on one of the meso-phenyl groups, while the meso-phenyl groups of the third NCP (3) are substituted with nitro, bromo, and methyl groups in an AB2C pattern. The specific regiochemistry of the aryl rings around the macrocycle in each porphyrin was definitively determined using a combination of 1D (1H and 13C) and 2D (gHMBC, gHSQC and ROESY) NMR spectroscopy. The absorption spectra of 1鈥?b>3 in CH2Cl2 are similar to those of N-confused tetraphenylporphyrin (NCTPP) but have Soret and Q bands that are shifted to lower energies with smaller extinction coefficients in comparison to those for NCTPP.