[22]Porphyrin-(3.1.1.3), a new vinylogous expanded porphyrin system.
Acid-catalyzed condensation of a pyrrole bisacrylaldehyde with a tripyrrane, followed by oxidation with ferric chloride, gave a [22]porphyrin-(3.1.1.3). This stretched macrocycle shows a strong diamagnetic ring current by (1)H NMR spectroscopy and gives red-shifted porphyrin-like UV-vis spectra; coordination with palladium(II) induces an EZ isomerization to accommodate the metal cation while retaining highly diatropic characteristics. [structure: see text]
Xu
Linlin
L
Department of Chemistry, Illinois State University, Normal, IL 61790-4160, USA.
Ferrence
Gregory M
GM
Lash
Timothy D
TD