| abstract |
A compound of formula (I): wherein W is independently selected from the group consisting of H, F, CI, Br, and I; X is independently selected from the group consisting of H, F, CI, Br, and I; Y is independently selected from the group consisting of F, CI, Br, and I; Z is independently selected from the group consisting of H, F, CI, Br, and I; n is an integer from 1 to 8; and n' is an integer from 1 to 12. |