Patent ID: 8440835

Claim:
An article, comprising: a compound of formula (I): wherein R 6 and R 7 are independently hydrogen, halogen, alkyl, or —NR 1 R 2 such that at least one of R 6 and R 7 is —NR 1 R 2 , R 1 and R 2 each independently being a substituted or unsubstituted alkyl; Y is a, —SH, —NHR 3 , —C(O)X 1 , -maleimidyl, —NHCOR 3 , —NHCO(CH 2 )X 2 , or —CH(NHR 3 )COOH; R 3 is hydrogen, substituted or unsubstituted alkyl, or an N-protecting group; X 1 is hydrogen, halogen, hydroxy, alkoxy, or O-succidimidyl; X 2 is hydrogen, halogen, hydroxy, alkoxy; and n is 0, 1, 2, or 3.