5,10-A2B2-type meso-substituted porphyrins--a unique class of porphyrins with a realigned dipole moment.
Current applications in porphyrin chemistry require the use of unsymmetrically substituted porphyrins. Many current industrial interests in optics and biomedicine require systems with either push-pull (electron-donating and -withdrawing groups) or amphiphilic systems (hydrophobic and hydrophilic groups). In this context we present the class of 5,10-A(2)B(2)-type porphyrins for which two different substituents are positioned in diagonally opposite meso positions. Thus, the intramolecular dipole moment in these tetrapyrroles is positioned along a β-β vector passing through two pyrrole rings. This is opposite to the situation of the frequently used 5,15-A(2)BC porphyrins for which the dipole moment is oriented along a meso-meso axis. We have elaborated syntheses of the 5,10-A(2)B(2) porphyrins by using transition-metal-catalyzed transformations of 5,10-A(2) porphyrins or direct substitutions reactions thereof; this gives the target molecules in 22-77% overall yields. The compounds exhibit interesting structural, spectroscopic, and optical features and can serve as building blocks for new porphyrin arrays and applications.
SFI Tetrapyrrole Laboratory, School of Chemistry, Trinity College Dublin, Dublin 2, Ireland. sengem@tcd.ie
Mathias O
MO
Senge
Claudia
C
Ryppa
Marijana
M
Fazekas
Monika
M
Zawadzka
Katja
K
Dahms
D002384:Catalysis; D018360:Crystallography, X-Ray; D015394:Molecular Structure; D011166:Porphyrins / Q000138:chemical synthesis* / Q000737:chemistry*; D013237:Stereoisomerism
D011166:Porphyrins