Effects of diphenyl-vinyl-substituted diketopyrrolopyrrole isomers on stacking and luminescence

Abstract

Two kinds of novel diphenyl-vinyl-substituted diketopyrrolopyrrole derivatives with different configurations, linear shaped R-4DPs vs. S shaped R-2DPs, were synthesized and characterized to explore their structural, optical, and electrochemical properties. The distinct placement of diphenyl significantly affected molecular planarity, conjugation and π–π stacking in the solid state, as confirmed by single-crystal X-ray diffraction analysis. The layer spacing of compounds with 4-diphenyl were approximately 3.30–3.40 Å. These molecules exhibited strong absorption in the visible region (350–680 nm) and emitted magenta fluorescence in solution, whereas 4-diphenyl-substituted derivatives (R-4DPs) displayed more intense absorption and redshift attributed to enhanced conjugation with linear and rigid configuration.