Synthesis, characterization, optical and electrochemical properties of a new chiral multichromophoric system based on perylene and naphthalene diimides

• A new chiral and multichromophoric macromolecular system (NPM) has been successfully synthesized.
• The collective absorption is higher with longer range absorption which is particularly very important in light harvesting applications.
• The observed absorption, emission and electrochemical characteristics are due to a delicate interplay of different intermolecular and intramolecular interactions in the macromolecule, both in solutions and the solid state.
• Solvent dependent tunability observed.
• NPM showed new and distinctive photophysical properties that are not observed in the monomeric states of the components and also in blends.
• Photoinduced electronic excitation energy transfer were noticed in various solvents from energy-harvested peripheral chromophores to the centered perylene core.

A new chiral and multichromophoric macromolecular system based on a perylene diimide chromophore consisting of two 1,4-bis(3-aminopropyl) piperazine linkers and two terminal chiral naphthalene bisimide chromophores has been synthesized. All of the chromophoric units are not π-conjugated with each other and could behave independently due to the presence of the nonconjugated linker. A new symmetrical dehydroabietyl substituted naphthalene diimide was also synthesized for comparison purposes. The bulky and chiral substituent is included at the peripheral positions of macromolecular system to increase the solubility and introduce directionality to the intermolecular interactions. The multichromophoric macromolecule showed new and distinctive photophysical properties that are different from the properties in the monomeric states of the components and in blends. It exhibited strong absorption in a wide range (320–600 nm) with enhanced light absorption due to higher molar absorption coefficients. It is observed that the absorption, emission and electrochemical characteristics are delicate interplay among intermolecular interactions in the macromolecule both in solutions and solid-state. Photoinduced electronic excitation energy transfer was noticed in various solvents from energy-harvested peripheral chromophores to the centered perylene core.

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