| abstract |
The present invention provides compounds of formula (I) and their use.n n n <Formula I>n n n n n n n n Wherein R f is C n F 2n + 1- (CH 2 ) m -where n is from 1 to 22 and m is 0 or an integer from 1 to 3; X is -CO 2- , -SO 3- , -CONH-, -O-, -S-, a covalent bond, -SO 2 NR- or -NR-, wherein R is H or C 1 to C 5 alkylene )ego; Y is -CH 2- , z is 0 or 1, R 1 is H, lower alkyl or R f -XY z -provided that X is -S- or -O-, m is 0, z Is 0, n ≧ 7, and when X is a covalent bond, m or z is 1 or more. |