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Synthesis of a Highly Amphoteric s ‐Indaceno[1,2,3‐ cd :5,6,7‐ c ′ d ′]diphenalene: Switching between Diatropism and Paratropism Due to Changes in Oxidation Level
Author(s) -
Murata Ichiro,
Sasaki Shigeru,
Klabunde KayUwe,
Toyoda Jiro,
Nakasuji Kazuhiro
Publication year - 1991
Publication title -
angewandte chemie international edition in english
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 0570-0833
DOI - 10.1002/anie.199101721
Subject(s) - dication , diamagnetism , ring (chemistry) , paramagnetism , benzene , chemistry , spectrum (functional analysis) , electromagnetic shielding , nuclear magnetic resonance , resonance (particle physics) , crystallography , stereochemistry , magnetic field , physics , molecule , atomic physics , condensed matter physics , organic chemistry , quantum mechanics
Despite the shielding caused by two negative charges , the resonance signals of H1, H7, H9 and H15 in the 1 H NMR spectrum of the dianion of 1 occur at lower field than in the spectrum of the corresponding dication. This behavior may be understood on the basis of HMO calculations, which predict diamagnetic ring currents along the periphery of the dianion 1 2⊖ , but weak paramagnetic ring currents in the central s‐indecene unit and the terminal benzene rings of dication 1 2⊕ .