Narrow Results

A convenient procedure for the synthesis of polyphenylene porphyrin dyads is described. The dyads consist of a meso-nitrophenylporphyrin covalently linked to a polyphenylene chain by an amide bond. The final phenyl group in the chain bears electron donor methoxy groups. The π-conjugated chain was obtained in excellent yield via a Wittig–Horner reaction, which produces a new double bond (E isomer) incorporating either —COOCH₃ or E isomer) incorporating either —CON(OCH₃)(CH₃) functional 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 E isomer) incorporating either —NO₂ groups in para positions of the peripheral phenyl rings give extra electron-withdrawing character to the porphyrin macrocycles. Coupling of the polyphenylene acids with aminoporphyrin results in the desired dyads. These dyads have moieties with different electron 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.

A dendritic shell can create a distinct micro-environment within its core. It also has the advantage of possessing unique photochemical, photophysical, electrochemical, and catalytic properties. Polyphenylene dendrons, which are characterized by their shape-persistent structures and out-of-plane twisted phenyl components, have previously been successfully attached to various functional groups. We have recently developed a convenient method for synthesizing a new type of porphyrazine that contains both flexible (linear) and more rigid (dendritic) groups. The synthesis of this completely aromatic and dendronic structure is unique in that it is based on a [2+4] Diels-Alder cycloaddition of tetraphenylcyclopentadienone to an ethynyl compound, followed by the elimination of carbon monoxide. In this study, tetrapyrazinoporphyrazinato metal and metal-free complexes were prepared by mixing 2,3-dicyano-5-polyphenylpyrazines with magnesium in n-butanol. The synthesized tetrapyrazinoporphyrazines were characterized by UV-visible spectroscopy, MALDI-TOF-MS (matrix-assisted laser desorption/ionization time-of-flight mass) spectrometry, elemental analysis and ¹H NMR spectroscopy.