Novel O-C-C-O and C-O-C-C stereochemistry in crown ether analogs. X-ray crystal structure and NMR studies of dibenzo-20-crown-6
The X-ray crystal structure of the title material indicates that the molecule possesses a pseudo-centre of inversion. A pair of O-C-C-O bonds have a trans conformation in contrast to normal gauche stereochemistry for such units in crown ethers. For the C-O-C-C networks, which are normally transoid in crown ethers, all four such units involving methylene carbons of the 20-membered ring exhibit unusual geometries. Two units possess gauche conformations and the other two have torsion angles near 120°. Solution 1H and 13C NMR spectra have been recorded as a function of temperature and 13C solid state spectra are included.
|Keywords||Crown ether, Solid state conformation|
|Journal||Canadian Journal of Chemistry|
Buchanan, G.W, Moghimi, A., & Bensimon, C. (1995). Novel O-C-C-O and C-O-C-C stereochemistry in crown ether analogs. X-ray crystal structure and NMR studies of dibenzo-20-crown-6. Canadian Journal of Chemistry, 73(1), 100–105. doi:10.1139/v95-015