wherein R1 is a solubilizing group selected from the group consisting of ethylene glycol oligomers, ethylene glycol polymers, ??-ammonium alkyl salts, ??-ammonium alkoxy salts, ??-ammonium oligoether salts, ??-sulfonate alkyl salts, ??-sulfonate alkoxy salts, and ??-sulfonate oligoether salts, wherein R2 is a solubilizing group selected from the group consisting of ethylene glycol oligomers, ethyl