Facile Incorporation of Pd(PPh₃)₂Hal Substituents into Polymethines, Merocyanines, and Perylene Diimides as a Means of Suppressing Intermolecular Interactions

Compounds with polarizable π systems that are susceptible to attack with nucleophiles at C–Hal (Hal = Cl, Br) bonds react with Pd­(PPh3)4 to yield net oxidative addition. X-ray structures show that the resulting Pd­(PPh3)2Hal groups greatly reduce intermolecular π–π interactions. The Pd-functionalized dyes generally exhibit solution-like absorption spectra in films, whereas their Hal analogues exhibit features attributable to aggregation.