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Zur Struktur von 2‐Azapentadienyllithium‐Verbindungen
Author(s) -
Wolf Gerhard,
Würthwein ErnstUlrich
Publication year - 1991
Publication title -
chemische berichte
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 0009-2940
DOI - 10.1002/cber.19911240333
Subject(s) - mndo , chemistry , lithium diisopropylamide , conformational isomerism , deprotonation , nuclear magnetic resonance spectroscopy , computational chemistry , crystallography , ab initio , stereochemistry , ab initio quantum chemistry methods , molecule , organic chemistry , ion
On the Structures of 2‐Azapentadienyllithium Compounds 2‐Azapentadienyllithium compounds 3 – 10 are easily accessible by deprotonation of N ‐allylimines 1,2 with lithium diisopropylamide. Their structures in THF solution at various temperatures are studied by means of 1 H‐ and 13 C‐NMR spectroscopy. 1‐Phenyl‐substituted 2‐aza‐pentadienyllithium derivatives adopt all‐trans W conformations, whereas 1‐alkylsubstituted 2‐azapentadienyllithium compounds show s‐cis conformations (sickle shapes). 13 C shifts of the 2‐azapentadienyl carbon atoms are discussed in terms of HOMO coefficients. The experimental structural results are compared with theoretical data obtained by MNDO and ab initio calculations for the corresponding anions. MNDO results are also given for monomeric 2‐azapentadienyllithium conformers 13,14 .