Synthesis of meso-nitrophenylporphyrins covalently linked to a polyphenylene chain bearing methoxy groups

A convenient procedure for the synthesis of polyphenylene porphyrin dyads i s described. The dyads consist of a meso-nitrophenylporphyrin covalently Li nked to a polyphenylene chain by an amide bond. The final phenyl group in t he chain bears electron donor methoxy groups. The pi-conjugated chain was o btained in excellent yield via a Wittig-Horner reaction, which produces a n ew double bond (E isomer) incorporating either -COOCH3 or -CON(OCH3)(CH3) f unctional groups. Expansion of the conjugated chain involves the reduction of these groups to aldehydes followed by a second Wittig-Horner reaction. 5 (4-Aminophenyl)-10,15,20-tris(4-nitrophenyl)porphyrin was synthesized from meso-(4-nitrophenyl)dipyrromethane. The -NO2 groups in pam positions of the peripheral phenyl rings give extra electron-withdrawing character to the p orphyrin macrocycles. Coupling of the polyphenylene acids with aminoporphyr in results in the desired dyads. These dyads have moieties with different e lectron donor-acceptor properties. This present strategy may be easily used for preparation of other similar dyad derivatives. These compounds can be suitable for photodynamic therapy. Copyright (C) 2000 John Wiley & Sons, Lt d.