The synthesis and full characterization of eight new calix[n]arene sulfonate esters including their conformational analysis were carried out. While p-tBu-calixarene and p-tBu-calixarene esters are conformationally labile in the temperature interval of 25-100°C, p-tBu-calixarene mono- and diesters were isolated as stable conformers at ambient temperature. Two 1,3-functionalised compounds of these derivatives, p-tert-butylcalixarene ditriflate (5) and dimesylate (6) were shown unexpectedly high conformational stability up to 100°C by dynamic NMR measurements. The NMR measurements confirm the pinched-cone conformation for both derivatives. For the dealkylated calixarene derivatives the partial cone conformer of the triesters have been obtained as major products in all cases.
|Number of pages||9|
|Publication status||Published - Dec 1 1998|
- 'Pinched cone' conformation
- Sulfonate esters
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