Synthesis, Characterization and Optical Properties of a Bay-Substituted Perylene Dye: N,N′-Didodecyl-1,7-di(2-Decyl-1-tetradecanoyl)- perylene-3,4:9,10-tetracarboxylic Acid Bisimide

Functionalization of perylene chromophore to result in a wide variety of perylene derivatives is a renowned strategy. Functionalization can be achieved by the substitution of corresponding groups at bay and imide positions of the conjugated aromatic perylene chromophore. In the current work, we have synthesized a new bay–substituted perylene diimide in three steps. We have selected the long aliphatic and branched aliphatic chains to substitute at imide and bay- positions, respectively, to promote the solubility as well as the electrical and optical characteristics. In the first step the raw compound perylene dianhydride was brominated at 1,7-positions of the perylene chromophore to result in brominated dianhydride (BrPDA). Subsequently, BrPDA was imidized at the imide positions of BrPDA with dodecyl amine to yield brominated perylene diimide (BrPDI). In the final step, the designed bay-substituted perylene diimide (PDI-Decanol) was synthesized upon substituting 2-decyl-1-tetradecanol at the bay positions of perylene core. The final compound was purified and the resulting PDI-Decanol was characterized by FTIR, UV-vis and fluorescence measurements. A detailed comparison on optical properties was made especially by studying the photophysics of the intermediate products along with the PDI-Decanol. The UV-vis absorption spectra of the three synthesized perylene derivatives in nonpolar aprotic solvents show regular characteristic π–π* absorption bands. Contrarily, absorption in dipolar aprotic solvents shows weak additional absorption bands (BrPDA in NMP; BrPDI in DMF; and PDI-Decanol in DMF and NMP; and iv methanol) at higher wavelengths which were remained after microfiltering the solution. Interestingly, the emission spectra of the three perylene derivatives have shown traditional three characteristic emission peaks and were not influenced by additional weak absorption bands. Keywords: Perylene, bay-substitution, brominated dianhydride, brominated diimide, aliphatic substituent.