6-[2-Carboxy-4(or 5)-[[(2,5-dioxo-1-pyrrolidinyl)oxy]carbonyl]phenyl]-1,2,10,11-tetrahydro-2,2,10,10-tetramethyl-4,8-bis(sulfomethyl)-pyrano[3,2-g:5,6-g′]diquinolin-13-ium inner salt compd. with N-ethyl-N-(1-methylethyl)-2-propanamine is a related compound of CAS# 247145-38-6, which is a new fluorescent dye that is more fluorescdent and more photostable than its commonly used spectral analog. The dyes are insensitive to pH in the 4-10 range. compound of CAS# 247145-38-6 can be used in terbium-based time-gated Forster resonance energy transfer imaging for evaluating protein-protein interactions on cell membranes and gain insight into drug loading and permeability.
