| abstract |
This invention relates to A crown ether of formula (I)n nwherein m is 4, 5, 6, 7, or 8 and i is, independently for each occurrence, 1 or 2; at least one occurrence in the crown ether of R 1 , R 2 and the carbon to which R 1 and R 2 are attached, said carbon being bound directly to an ether oxygen of formula (I), form together a group of formula (II)n nwherein L is a linker which is absent or selected from a covalent bond and n(CR 5 R 6 ) n , useful as carriers for pharmaceutical and diagnostic compositions. |