Cover Picture: Siamese‐Twin Porphyrin: A Pyrazole‐Based Expanded Porphyrin of Persistent Helical Conformation (Chem. Eur. J. 19/2013). Issue 19 (2nd May 2013)

• Record Type: Journal Article
• Authors: Blusch, Lina K.; Hemberger, Yasmin; Pröpper, Kevin; Dittrich, Birger; Witterauf, Franziska; John, Michael; Bringmann, Gerhard; Brückner, Christian; Meyer, Franc
• Is Part Of: Chemistry. Volume 19:Issue 19(2013)
• Page Start: 5769
• Page End: 5769
• Publication Date: 2013-05-02
• Subjects: Chemistry -- Periodicals; 540
• DOI: 10.1002/chem.201390065
• Languages: English
• ISSNs: 0947-6539

Abstract

<abstract abstract-type="graphical" xml:lang="en"> <title> <x xml:space="preserve">Abstract</x> </title> <p>Expanded porphyrins The synthesis of the long sought‐after pyrazole‐based expanded porphyrin and its homobimetallic nickel(II) and copper(II) complexes is described in the Full Paper by G. Bringmann, C. Brückner, F. Meyer et al. on <ext-link ext-link-type="doi" xlink:type="simple" xmlns:xlink="http://www.w3.org/1999/xlink">page 5868 ff.</ext-link> Spectroscopic evidence, as well as structural parameters of this hexaphyrin analogue (named the Siamese‐twin porphyrin), proved it to be non‐aromatic, though each half of the molecule is fully conjugated. In the complexes, each metal ion is coordinated in a square‐planar fashion by a dianionic, porphyrin‐like {N₄} binding pocket. The conformations of the diprotonated macrocycle and its metal complexes are all strongly twisted. The persistent helical twist permitted resolution of the enantiomeric helimers by HPLC on a chiral phase.<boxed-text content-type="graphic" position="anchor" orientation="portrait"><graphic position="anchor" mimetype="image" xlink:href="ark:/27927/pgg1ztb0s08" orientation="portrait" xlink:type="simple" xmlns:xlink="http://www.w3.org/1999/xlink" /></boxed-text></p> </abstract>