Patent ID: 7737169

Claim:
A compound represented by the formula: wherein: R 1 is selected from the group consisting of —CO—CH 2 —NH 2 , —CO—CH 2 —CH 2 —CH 2 —NH 2 , —CO—CH(CH 2 —CH 2 —COOH)—NH 2 and —CO—CH 2 —CH 2 —CH(COOH)—NH 2 ; R 2 and R 3 are selected from hydrogen, a substituted or unsubstituted alkyl group, or R 2 and R 3 together form a substituted or unsubstituted cycloalkyl group; R 4 is a group represented by the formula: —O—CH 2 CH(OPO 3 2− )CH 2 OPO 3 2− , or —OCH(CH 2 OPO 3 2− ) 2 , or —O—CH 2 (CHOPO 3 2− ) 2 CH 2 OPO 3 2− , or —O—CH 2 C(CH 2 OPO 3 2− ) 3 , or —O(CH 2 ) a OP 2 O 6 3− , or —O(CH 2 ) a OP 3 O 9 4− wherein when a is present in the formula, it is an integer between 1 and 5; and R 5 is hydrogen, a substituted or unsubstituted alkyl group, a substituted or unsubstituted phenyl group, a triplet sensitizing group selected from the group consisting of unsubstituted and substituted benzophenones, substituted and unsubstituted anthrones, substituted and unsubstituted xanthones, substituted and unsubstituted carbazoles, substituted and unsubstituted triphenylenes and substituted and unsubstituted 3- or 4-benzoylpyridines, a group represented by (CH 2 ) n Y or (CH 2 ) m —O—(CH 2 ) n Y; wherein m and n are independently between 1 and 10 and Y is selected from hydrogen, CO 2 H or salts thereof, OPO 3 2− or salts thereof, OSO 3 − or salts thereof, or CO 2 R 6 , wherein R 6 is an alkyl or substituted alkyl group; or a salt, protected form or partially or fully protonated form of the compound.