Publikace na Přírodovědecká fakulta |
2002
Abstrakt
A biscalixarene bearing tert-butylated and de-tert-butylated calix[4]arene unit connected by four ethylenox bridges has been prepared. This compound adopts the pinched cone conformation (C-2v symmetry) and hence. is suitable preorganised for Ag- complexation.
X-ray crystallography showed that the silver cation (soft) is sandwiched by the two distal coplanar phenyl rings of the de-tert-butylated part of the molecule possessing a eta(1) binding mode. The complexatio'n of the K+ cation (hard) into the central cavity created by the bridging moieties leads to a change of conformation (C-4v symmetry) and hence. to the complete loss of complexation ability towards the Ag+ cation