Synthesis and Characterisation of 1,7-Di- and Inherently Chiral 1,12-Di- and 1,6,7,12-Tetraarylperylenetetracarbox-3,4:9,10-diimides



By using the Suzuki–Miyaura reaction, a variety of 1,7- and 1,12-disubstituted and 1,6,7,12-tetraaryl-substituted perylenetetracarbox-3,4:9,10-diimides have been synthesised starting from the corresponding halogen derivatives. Until now, the 1,12- and 1,6,7,12-sustitutions were difficult to access and only single examples have been reported. Dehydrohalogenation was observed to be competitive with the Suzuki–Miyaura reaction. The extent of this side reaction depends on the substitution pattern of the perylene diimide core and on the nature of the boronic acid derivative. Photochemical pericyclisation also reduces the yield of the desired products. A mechanistic analysis has been performed on the special case of 1,12-diphenylperylenediimides, in which benzene is eliminated as a consecutive process of such a reaction. The energies of the frontier orbitals were determined. By using cyclic voltammetry, the energy of the LUMO was measured, and the energy gap between the frontier orbitals was determined based on optical spectroscopy (UV and fluorescence). With these two parameters, the energies of the HOMO were determined. The 1,6,7,12-tetraaryl- and 1,12-diarylperylenediimides have been optically resolved by using HPLC with a chiral stationary phase. Determination of absolute configuration was carried out by recording circular dichroism (CD) spectra of the enantiomers.