Patent ID: 8703970

Claim:
A compound having a formula: wherein W and X are hydrogen or —COOY, at least one of W and X is —COOY, and Y is hydrogen or C 1 -C 6 alkyl; LG − is Cl − , PhCH 2 CO 2 − , PhS − , PhCH 2 S − , PhO − , HO − , or HS − ; R is C 1 -C 6 alkyl; and A is a chromophore that is photochemically stimulated to react with the carbon atom bearing LG and photolyze LG from the compound, and A is a chromophore selected from a group consisting of thioxanthene-type chromophores having a structure wherein R 1 -R 6 are each independently hydrogen or halogen; xanthene-type chromophores having a structure wherein R 1 -R 6 are each independently hydrogen or halogen; fluorescein-type chromophores having a structure rhodamine-type chromophores having a structure