Aromatic interactions in the synthesis and conformation of two collapsible tetracationic cyclophanes

The conformations of tetracationic paracyclophane and metacyclophane derivatives containing quaternary salts of para-2,2-diazaterphenyl were investigated. The molecules were synthesized as the bromide and hexafluorophosphate salts which allowed solubility in aqueous and organic solvents. Molecular m...

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Bibliographic Details
Published inTetrahedron Vol. 57; no. 15; pp. 2991 - 2996
Main Authors Sindkhedkar, MD, Mulla, HR, Wurth, MA, Cammers-Goodwin, A
Format Journal Article
LanguageEnglish
Published OXFORD Elsevier 09.04.2001
Subjects
Chemistry
Chemistry, Organic
Physical Sciences
Science & Technology
molecular mechanics
solvation
GB/SA
cyclophane
conformation
molecular tweezers
dynamic NMR
CATIONS
BENZO-18-CROWN-6
MINIMALIST
pi-stacking
molecular recognition
anion binding
TO-FACE
DERIVATIVES
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Summary:The conformations of tetracationic paracyclophane and metacyclophane derivatives containing quaternary salts of para-2,2-diazaterphenyl were investigated. The molecules were synthesized as the bromide and hexafluorophosphate salts which allowed solubility in aqueous and organic solvents. Molecular mechanics led to the notion that these cyclophanes would populate collapsed and open conformations in water and only populate open conformers in organic solvent. VT NMR studies indicated that the open and the collapsed conformers did not exchange on the NMR timescale. Large, positively charged clefts in one of these conformers bound flat anions between pyridinium rings as would molecular-scale tweezers. (C) 2001 Elsevier Science Ltd. All rights reserved.
ISSN:0040-4020
DOI:10.1016/S0040-4020(01)00162-4