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Cover Picture: Siamese‐Twin Porphyrin: A Pyrazole‐Based Expanded Porphyrin of Persistent Helical Conformation (Chem. Eur. J. 19/2013)
Author(s) -
Blusch Lina K.,
Hemberger Yasmin,
Pröpper Kevin,
Dittrich Birger,
Witterauf Franziska,
John Michael,
Bringmann Gerhard,
Brückner Christian,
Meyer Franc
Publication year - 2013
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Reports
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201390065
Subject(s) - porphyrin , chemistry , pyrazole , crystallography , enantiomer , stereochemistry , metal , molecule , photochemistry , organic chemistry
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 page 5868 ff. 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 {N 4 } 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.