New water-soluble calixarenes bearing sulphonate groups on the ‘lower rim’: the relation between calixarene shape and binding ability

Abstract

Association constants have been determined for pyrene as a guest molecule for 9 water-soluble calix[n]arenes (n= 4, 6, and 8) bearing sulphonate groups on the ‘upper rim’(1) or on the ‘lower rim’(2). The results have established that calixarene (1) has a strong but non-selective binding site whereas calixarene (2) has a relatively weak but selective binding site.