TY - JOUR
T1 - Aromatic pathways in thieno-bridged porphyrins
T2 - Understanding the influence of the direction of the thiophene ring on the aromatic character
AU - Fliegl, Heike
AU - Özcan, Nergiz
AU - Mera-Adasme, Raul
AU - Pichierri, Fabio
AU - Jusélius, Jonas
AU - Sundholm, Dage
N1 - Funding Information:
This research has been supported by the Academy of Finland through its Computational Science Research Programme (LASTU). We thank Tohoku University and Magnus Ehrnrooth foundation for financial support. CSC – the Finnish IT Center for Science – is acknowledged for computer time. H. F. thanks for support by the Norwegian Research Council through the CoE Centre for Theoretical and Computational Chemistry (Grant No. 179568/V30). This work has received support from the Norwegian Supercomputing Program (NOTUR) through a grant of computer time (Grant No. NN4654K).
PY - 2013/7/1
Y1 - 2013/7/1
N2 - Magnetically induced current densities have been investigated for some recently synthesised thieno-bridged porphyrins. The aim of the study is to understand the influence of the direction of the thieno bridge on the aromatic character of the molecules. The calculated ring-current susceptibilities for two tautomers of 2,3-and 3,4-thieno-bridged porphyrins as well as of the corresponding Zn-containing compounds show that the molecules are all aromatic according to the ring current criterion. The ring-current susceptibilities of 16.2 nA/T and 20.2 nA/T around the porphyrin ring of the two tautomers of 2,3-thieno-bridged porphyrin are somewhat weaker than the ring-current susceptibilities of 22.8 nA/T and 23.8 nA/T obtained for the two tautomers of 3,4-thieno-bridged porphyrin. For 2,3-thieno-bridged porphyrin, the positions of the inner hydrogens affect the ring-current susceptibility more than for 3,4-thieno-bridged porphyrin. The current pathways of the Zn porphyrinoids are a superposition of the pathways of the two trans tautomers of the corresponding free-base porphyrinoids. The current-density calculations explain the different aromatic character of 2,3-thieno-bridged and 3,4-thieno-bridged porphyrins. Current-density calculations on tetra-2,3-thieno-bridged and tetra-3,4-thieno-bridged porphyrins yielded similar current pathways as obtained for mono-substituted thieno-bridged porphyrins. Tetra-2,3-thieno-bridged porphyrin is practically non-aromatic since it sustains a very weak ring current of 2.6 nA/T. The calculated ring-current susceptibilities for tetra-3,4-thieno-bridged porphyrin is 13.2 nA/T, which can be compared to the ring-current susceptibilities of 11.8 and 27.5 nA/T for benzene and free-base porphyrin, respectively.
AB - Magnetically induced current densities have been investigated for some recently synthesised thieno-bridged porphyrins. The aim of the study is to understand the influence of the direction of the thieno bridge on the aromatic character of the molecules. The calculated ring-current susceptibilities for two tautomers of 2,3-and 3,4-thieno-bridged porphyrins as well as of the corresponding Zn-containing compounds show that the molecules are all aromatic according to the ring current criterion. The ring-current susceptibilities of 16.2 nA/T and 20.2 nA/T around the porphyrin ring of the two tautomers of 2,3-thieno-bridged porphyrin are somewhat weaker than the ring-current susceptibilities of 22.8 nA/T and 23.8 nA/T obtained for the two tautomers of 3,4-thieno-bridged porphyrin. For 2,3-thieno-bridged porphyrin, the positions of the inner hydrogens affect the ring-current susceptibility more than for 3,4-thieno-bridged porphyrin. The current pathways of the Zn porphyrinoids are a superposition of the pathways of the two trans tautomers of the corresponding free-base porphyrinoids. The current-density calculations explain the different aromatic character of 2,3-thieno-bridged and 3,4-thieno-bridged porphyrins. Current-density calculations on tetra-2,3-thieno-bridged and tetra-3,4-thieno-bridged porphyrins yielded similar current pathways as obtained for mono-substituted thieno-bridged porphyrins. Tetra-2,3-thieno-bridged porphyrin is practically non-aromatic since it sustains a very weak ring current of 2.6 nA/T. The calculated ring-current susceptibilities for tetra-3,4-thieno-bridged porphyrin is 13.2 nA/T, which can be compared to the ring-current susceptibilities of 11.8 and 27.5 nA/T for benzene and free-base porphyrin, respectively.
KW - aromatic pathways
KW - aromatic switches
KW - aromaticity
KW - gauge including magnetically induced current densities
KW - porphyrinoids
KW - porphyrins
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U2 - 10.1080/00268976.2013.794397
DO - 10.1080/00268976.2013.794397
M3 - Article
AN - SCOPUS:84882455936
VL - 111
SP - 1364
EP - 1372
JO - Molecular Physics
JF - Molecular Physics
SN - 0026-8976
IS - 9-11
ER -