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Helicene Dianions: Paratropicity of Twisted Phenanthrene Dianions
Author(s) -
Frim Ron,
Mannschreck Albrecht,
Rabinovitz Mordecai
Publication year - 1990
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.199009191
Subject(s) - phenanthrenes , helicene , chemistry , phenanthrene , alkyl , proton nmr , twist , proton magnetic resonance , crystallography , planar , lithium (medication) , stereochemistry , nuclear magnetic resonance , molecule , organic chemistry , physics , geometry , medicine , mathematics , endocrinology , computer graphics (images) , computer science
Non‐planar, alkyl‐substituted phenanthrenes are reduced to the dianions 1a–c with metallic lithium and sodium in [D 8 ] THF . The paratropic chemical shifts in the 1 H ‐ NMR spectrum and the linewidths of the signals of all dianions depend in the same way on the angle of twist: the greater the twist, the better the resolution of the 1 H ‐ NMR signals and the smaller the upfield shifts.