Synthesis of Dendritic Porphyrin Based on Click Reaction

Dendritic zinc(II)-porphyrin bearing carbazole units at the terminals has been prepared via click reaction of azide-substituted Zn-porphyrin precursors and carbazole-based terminal alkyne under [Cu(NCCH3)4][PF6] catalysis. 5,10,15,20-Tetrakis(3,5-bis(azidomethyl)-2,4,6-trimethylphenyl)porphyrin is synthesized from Lindsey reaction between 3,5-bis(azidomethyl)-2,4,6-trimethylbenzaldehyde and pyrrole in CH2Cl2 and BF3.OEt2 catalyst. Carbazole-based terminal alkyne is made from Friedel – Crafts alkylation, Ullmann coupling and Sonogashira coupling. The structure of products is confirmed by mass spectrometry and nuclear magnetic resonance spectroscopy (1H NMR, 13C NMR). The MALDI – TOF spectrum shows the peak that corresponds with molecular weight of target dendritic porphyrin. Then there appears a new methylene peak diagnostic for the formation of triazole groups in dendrimer.