Chemically Induced Breathing of Flexible Porphyrinic Covalent Cages

The synthesis of two flexible bis-porphyrin cages 3 and 4, incorporating respectively Zn­(II) porphyrins and free-base porphyrins, is reported. In both cages, the four covalent linkers that bind the two porphyrins are functionalized with two 1,2,3-triazolyl ligands. These cages were characterized by...

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Bibliographic Details
Published in:Journal of organic chemistry 2017-06, Vol.82 (11), p.5845-5851
Main Authors: Schoepff, Laetitia, Kocher, Lucas, Durot, Stéphanie, Heitz, Valérie
Format: Article
Language:English
Subjects:
Chemical Sciences
Material chemistry
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Summary:The synthesis of two flexible bis-porphyrin cages 3 and 4, incorporating respectively Zn­(II) porphyrins and free-base porphyrins, is reported. In both cages, the four covalent linkers that bind the two porphyrins are functionalized with two 1,2,3-triazolyl ligands. These cages were characterized by NMR and HRMS, and for cage 3 incorporating 1,4-diazabicyclo[2.2.2]­octane (DABCO), an X-ray crystallographic structure was obtained. Chemically induced conformational changes are studied and compared to those of two related cages with longer flexible linkers. Binding of four silver­(I) ions to the peripheral ligands opens the flattened structures in solution and locks the two porphyrins in a face-to-face disposition. Addition of an excess of acid fully expands the cages due to electrostatic repulsion between the positively charged sites. These two reversible processes allow for a chemically induced breathing of the flexible structures.
ISSN:0022-3263
1520-6904
DOI:10.1021/acs.joc.7b00698