Synthesis and spectroscopic studies of 3,6-diphenyl-2,5-dihydropyrrolo[3,4-c]pyrrole-1,4-dion's N,N'-dialkyl derivatives.

3,6-diaryl-2,5-dihydro-1,4-diketopyrrolo[3,4-c]pyrrole-1,4-dione (DPPD) derivatives are used commercially as red pigments, because of their color strength, brightness, and very low solubility in most common solvents. These products, although highly colored, appear to be of limited value as dyes, since they show a tendency to form an aggregate when incorporated into a solvent. Monoalkyl and dialkyl derivatives of DPPD were synthesized and then characterized with IR, 1HNMR, UV-Vis absorption and emission spectroscopy. Molar absorption coefficient, singlet energy level and Stokes' shift values of DPPD derivatives were declared. Monoalkyl and dialkyl derivatives of DPPD's solubilities were measured from saturated solutions of dimethylformamide (DMF), tetrahydrofuran (THF), dichloromethane (DCM), acetonitrile (ACN) and toluene and they are compared with each other.