Even with Sands, these dyes are considered proprietary in some cases, and they will not tell you the structure. They will only supply a suggested solvent and a curve of the spectrum.

In any case, don't take ANY dyes containing Selenium. They are too toxic for home use and need industrial quality equipment for safe handling. Sands sent me one for a test, and it remains in their safe packing material in a refrigerator dedicated to chemicals. Paul Gilman saw the dye, knew what it was and told me to never use it due to its toxicity.