Cobaltabis(dicarbollide) derivatives as extractants for europium from nuclear wastes

Carbon substituted derivatives of [3,3′-Co(1-Me-2-R-1,2-C2B9H9)2]– incorporating lipophilic chains [R = (CH2)3O(CH2)2OMe 1, (CH2)3OCH2CHMe2 2, (CH2)6O(CH2)3Me 3, (CH2)3Me 4], are synthesized for the first time and tested for extraction of 152Eu; compound 3 showed the best performance, and it proved to have higher efficiency in transport at low acidity than the well known calixarene derivatives.