Patent ID: 8742114

Claim:
A compound having the formula: wherein: X is O, S, or C(CH 3 ) 2 ; Each of R 1 or R 6 is independently hydrogen, carboxy, sulfo, halogen, CN, or alkoxy; Each of t and s is an integer from 0 to 4; R 2 is an alkyl, or alkyl group substituted by a carboxy, a sulfo, or a phosphate; R 3 is H, or C 6 H 4 CH 2 N(CH 2 CH 3 ) 2 ; R 4 is H, alkyl, heteroalkyl, arylalkyl, aryl, cycloalkyl, heterocycloalkyl, halogen, alkoxy, alkylamino, or alkylthio; R 5 is —(CH 2 ) a —[O—(CH 2 ) b ] m —O—Z, where Z is H, alkyl, carboxy, sulfo, or phosphate; each of a and b is an integer from 1 to 4; m is an integer selected from 1 to 12; n is 0, 1, or 2; ψ− is Cl − , Br − , or I − .