The formation of endo-complexes between calixarenes and amines--a reinvestigation.
The formation of an endo-complex between p-allylcalix[4]arene and t-butylamine was described by Gutsche in 1985. However, for a comparable system, it has been shown using NOE methods that the amine does not reside inside the calix. Instead, an exo-calix complex is formed. A reevaluation suggests that the previous conclusion is an artifact due to improper NMR-data processing. DFT (RB3LYP/6-31G(d)) calculations confirm the higher stability of the exo-complex over its endo-counterpart.
Computer-Chemie-Centrum, Friedrich-Alexander-Universität Erlangen-Nürnberg, Nägelsbachstrasse, 25, 91052, Erlangen, Germany.
Ralph
R
Puchta
Timothy
T
Clark
Walter
W
Bauer
D000588:Amines / Q000737:chemistry*; D047250:Calixarenes / Q000737:chemistry*; D006860:Hydrogen Bonding; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008968:Molecular Conformation
D000588:Amines; D047250:Calixarenes