TY - JOUR
T1 - Planar Antiaromatic Core-Modified 24π Hexaphyrin(1.0.1.0.1.0) and 32π Octaphyrin(1.0.1.0.1.0.1.0) Bearing Alternate Hybrid Diheterole Units
AU - Ajay, Jayaprakash
AU - Shirisha, Sriram
AU - Ishida, Masatoshi
AU - Ito, Kosuke
AU - Mori, Shigeki
AU - Furuta, Hiroyuki
AU - Gokulnath, Sabapathi
N1 - Funding Information:
S.S. and S.G. thank the CSIR-Indian Institute of Chemical Technology for the initial stage of this work. S.G. acknowledges the DST-Inspire Faculty Fellowship, New Delhi (India) and IISER Thiruvananthapuram for facilities. A.J. thanks the Inspire Fellowship, New Delhi (India). The work in Kyushu was supported by JSPS KAKENHI (Grant numbers JP15K12646 to H.F., and JP16K05700 and JP17H05377 to M.I.
Publisher Copyright:
© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
PY - 2019/2/21
Y1 - 2019/2/21
N2 - The Lewis acid catalyzed self-condensation of hybrid diheterole (furan-pyrrole and thiophene-pyrrole) precursors has afforded novel Hückel antiaromatic 24π hexaphyrin(1.0.1.0.1.0) and 32π octaphyrin(1.0.1.0.1.0.1.0) structures without β-annulated bridges. Single-crystal X-ray diffraction analysis of the hybrid porphyrinoids (S 3 N 3 -ox and O 4 N 4 -ox) revealed a nearly planar conformation and the 1 H NMR spectra suggest the presence of paratropic ring currents. These antiaromatic macrocycles show characteristic optical features and underwent reversible two-electron reduction to Hückel aromatic 26π- and 34π-electron species, respectively, as is evident from the results of spectroscopic and theoretical studies (nucleus-independent chemical shift (NICS) and anisotropy of the current-induced density (ACID) calculations). The incorporation of hybrid diheteroles alternately into expanded porphyrin skeletons provides a novel approach to the fine-tuning of the electronic structures of planar antiaromatic macrocycles.
AB - The Lewis acid catalyzed self-condensation of hybrid diheterole (furan-pyrrole and thiophene-pyrrole) precursors has afforded novel Hückel antiaromatic 24π hexaphyrin(1.0.1.0.1.0) and 32π octaphyrin(1.0.1.0.1.0.1.0) structures without β-annulated bridges. Single-crystal X-ray diffraction analysis of the hybrid porphyrinoids (S 3 N 3 -ox and O 4 N 4 -ox) revealed a nearly planar conformation and the 1 H NMR spectra suggest the presence of paratropic ring currents. These antiaromatic macrocycles show characteristic optical features and underwent reversible two-electron reduction to Hückel aromatic 26π- and 34π-electron species, respectively, as is evident from the results of spectroscopic and theoretical studies (nucleus-independent chemical shift (NICS) and anisotropy of the current-induced density (ACID) calculations). The incorporation of hybrid diheteroles alternately into expanded porphyrin skeletons provides a novel approach to the fine-tuning of the electronic structures of planar antiaromatic macrocycles.
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U2 - 10.1002/chem.201805861
DO - 10.1002/chem.201805861
M3 - Article
C2 - 30589136
AN - SCOPUS:85060864655
SN - 0947-6539
VL - 25
SP - 2859
EP - 2867
JO - Chemistry - A European Journal
JF - Chemistry - A European Journal
IS - 11
ER -