Abstract
A high yielding (93%), regiospecific synthesis of cis(4,4')-di(carbomethoxybenzo)-30-crown-10 (1c) is reported. The derived crown ether diol 1d was converted to pyridyl cryptand 12 in 44% yield by reaction with pyridine-2,6-dicarbonyl chloride. Binding of two different 4,4'-bipyridinium (paraquat) species (3) and 2,2'-bipyridinium (diquat) 4 by 12 was explored via (1)H NMR spectroscopy, NOE experiments, mass spectrometry, X-ray crystallographic analyses, and isothermal titration calorimetry. Cryptand 12 exhibits the highest association constant for diquat ever reported (Ka = 1.9 x 10(6) M(-1)) and very high association constants for paraquats (Ka > 10(5) M(-1)) in acetone at 22 degrees C. The binding constant of diquat 4 by cryptand 12 is nearly 6-times higher than any other reported host.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: 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.
