Preparation, structures and preliminary host-guest studies of fluorinated syn-bis-quinoxaline molecular tweezers.
A series of polycyclic frameworks with fluorinated syn-facial quinoxaline sidewalls has been prepared as potential molecular tweezers for electron-rich guest compounds. Our synthetic route to the cyclooctadiene-derived scaffolds 16a-d takes advantage of the facile isolation of a novel spirocyclic precursor 9b with the crucial syn-orientation of its two alkene moieties. The crystal structure of 16c displays two features typical of a molecular tweezer: inclusion of a solvent molecule in the molecular cleft and self-association of the self-complementary scaffolds. Furthermore, host-guest NMR studies of compound 16c in solution show chemical exchange between the unbound and bound electron-rich guest, N,N,N',N'-tetramethyl-p-phenylenediamine.
Etzkorn
Markus
M
Department of Chemistry, The University of North Carolina at Charlotte, 9201 University City Blvd., Charlotte, NC 28223, USA. metzkorn@uncc.edu
Timmerman
Jacob C
JC
Brooker
Matthew D
MD
Yu
Xin
X
Gerken
Michael
M