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Updated: Nov 3, 2025

Synthesis of pH Dependent Pyrazole, Imidazole, and Isoindolone Dipyrrinone Fluorophores using a Claisen-Schmidt Condensation Approach
Published on: June 10, 2021
Tripyrrin-armed isosmaragdyrins: synthesis, heterodinuclear coordination, and protonation-triggered helical inversion
Chengjie Li1, Kai Zhang1, Masatoshi Ishida2
1Key Laboratory for Advanced Materials, Joint International Research Laboratory of Precision Chemistry and Molecular Engineering, Feringa Nobel Prize Scientist Joint Research Center, Shanghai Key Laboratory of Functional Materials Chemistry, School of Chemistry and Molecular Engineering, East China University of Science & Technology Shanghai 200237 China yshxie@ecust.edu.cn.
Abstract:
Oxidative ring closure of linear oligopyrroles is one of the synthetic approaches to novel porphyrinoids with dinuclear coordination sites and helical chirality. The spatial arrangement of the pyrrolic groups of octapyrrole (P8) affected the position of the intramolecular oxidative coupling of the pyrrolic units; tripyrrin-armed isosmaragdyrin analogue (1) containing a β,β-linked bipyrrole moiety was synthesized regioselectively in a high yield by using FeCl3. NiII-coordination at the armed tripyrrin site of 1 allowed the formation of diastereomeric helical twisted complexes (2A and 2B) and succeeding CuII-coordination at the macrocyclic core afforded heterodinuclear NiII/CuII-complexes (3A and 3B). Each of them comprised a pair of separable enantiomers, exhibiting P- and M-helices, respectively. Notably, diastereomeric interconversion from 2A to 2B was quantitatively achieved as a consequence of helical transformation under acidic conditions.
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