TY - JOUR
T1 - Differential substituent effects of β-halogens in water-soluble porphyrins
AU - Biffinger, Justin C.
AU - Sun, Haoran
AU - Nelson, Andrew P.
AU - DiMagno, Stephen G.
PY - 2003/2/21
Y1 - 2003/2/21
N2 - The first water-soluble β-octafluorinated porphyrins, 5,10,15,20-tetrakis(4-sulfonatophenyl)-2,3,7,8,12,13,17,18-octafluoroporphyrin, 1, and 5,10,15,20-tetrakis(2,6-difluoro-3-sulfonatophenyl)-2,3,7,8,12,13,17,18-octafluo roporphyrin, 2, have been prepared and their aqueous aggregation, acid-base, and optical properties have been characterized. The porphyrins are tetraanionic at neutral pH (at pH = 3-11 for 1 and pH = 0-9 for 2). Semiempirical (AM1) calculations provide evidence that somewhat unusual acidity characteristics of the fluorinated compounds (with respect to similar brominated porphyrins) can be rationalized solely on the basis of chemical hardness and electronegativity arguments. These results indicate that the large conformational differences seen in the structures of brominated and fluorinated water-soluble porphyrins have little impact upon N-H acidity. Metalation of 1 and 2 with ZnCl2 yielded the zinc complexes, which were characterized by optical spectroscopy and electrochemistry.
AB - The first water-soluble β-octafluorinated porphyrins, 5,10,15,20-tetrakis(4-sulfonatophenyl)-2,3,7,8,12,13,17,18-octafluoroporphyrin, 1, and 5,10,15,20-tetrakis(2,6-difluoro-3-sulfonatophenyl)-2,3,7,8,12,13,17,18-octafluo roporphyrin, 2, have been prepared and their aqueous aggregation, acid-base, and optical properties have been characterized. The porphyrins are tetraanionic at neutral pH (at pH = 3-11 for 1 and pH = 0-9 for 2). Semiempirical (AM1) calculations provide evidence that somewhat unusual acidity characteristics of the fluorinated compounds (with respect to similar brominated porphyrins) can be rationalized solely on the basis of chemical hardness and electronegativity arguments. These results indicate that the large conformational differences seen in the structures of brominated and fluorinated water-soluble porphyrins have little impact upon N-H acidity. Metalation of 1 and 2 with ZnCl2 yielded the zinc complexes, which were characterized by optical spectroscopy and electrochemistry.
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U2 - 10.1039/b209345f
DO - 10.1039/b209345f
M3 - Article
C2 - 12929463
AN - SCOPUS:0042820378
SN - 1477-0520
VL - 1
SP - 733
EP - 736
JO - Organic and Biomolecular Chemistry
JF - Organic and Biomolecular Chemistry
IS - 4
ER -