Abstract
Examination of the pseudorotaxane-like geometries adopted in the solid state by a series of 1:1 complexes revealed significant differences in the hydrogen bonding interactions between oxygen atoms in some hydroquinone-based guests carrying polyether/polyester functions and the acidic hydrogen atoms on the bipyridinium units of the hostcyclobis(paraquat-p-phenylene). These differences are reflected directly in the stabilities of the complexes in solution and dramatic changes in the magnitudes of their association constants (Ka values ranging from 130 to 4300 M-1 in MeCN at 25 °C) are observed upon varying the location of the carbonyl ester function(s) along the polyether/ester chains. A similar effect (Ka values ranging from 5 to 730 M-1 in Me2CO at 25 °C) was observed in the binding of paraquat as its bipyridinium bis(hexafluorophosphate) salt by analogous macrocyclic hydroquinone-based mono- and bis-lactones. Investigations of the kinetics of hydrolyses of the ester functions revealed thatwhile inert in ...
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.