Effects of Core and/or Peripheral Protonation of meso-Tetra(2-, 3-, and 4-pyridyl)Porphyrin and meso-Tetra(3-methylpyridyl)Porphyrin on Their UV-vis Spectra

Table 5

UV-vis spectral data for interaction of H₂t(py)P with CH₃COOH in CH₂Cl₂^a,b.

Porphyrins and the dications	Soret band	Q(0,0) band
	(λ/nm)	(λ/nm)
H2t(2-py)P	417.0	642.0
[H4t(2-pyp)P](CH3COO)2	440.8	654.3
Δν (cm^−1)	−1294.0	−293.0
H2t(3-py)P	418.0	646.4
[H4t(3-py)P](CH3COO)2	444.0	652.0
Δν (cm^−1)	−1400.9	−132.8
H2t(4-py)P	416.0	643.0
[H4t(4-py)P](CH3COO)2	428.9	639.6
Δν (cm^−1)	−722.1	82.7

aSee the footnotes of Table 2. bExcess amounts of acetic acid was used to complete the reaction (seeSection  2.4for details).