Patent ID: 7417164

Claim:
The compound: wherein: R 2 is R 3 is —(CH 2 ) n —A − M + , wherein n is 1-4, wherein A − is an anionic group selected from the group consisting of SO 3 − , HPO 3 − , CO 2 − and and wherein M + is a cationic group selected from the group consisting of H + , an alkali metal ion, Li + , Na + , K + , Rb + , Cs + , Fr + , an onium ion and NR 4 + , wherein R is selected from the group consisting of alkyl, alkylaryl and aromatic groups); R 4 is R 5 is selected from the group consisting of wherein n is equal to 1-10, n′ is equal to 2-4 and Y is selected from the group consisting of NH and O; R 6 is selected from the group consisting of NHR 7 , OR 7 and CO 2 H; and R 7 is H or an ethylenically unsaturated group selected from the group consisting of methacryloyl, acryloyl, styryl, acrylamido and methacrylamido.