Computational Design of Long-Wavelength Absorbing and Emitting Carbostyrils

Abstract

We have used computational chemistry methods to aid the rational design of long-wavelength absorbing and emitting organic materials. For this purpose, the vertical electronic transition energies of 3,4-dicyano carbostyriles (quinolone-2(1H)-ones) substituted by electron-donating substituents at positions 6 and 7, are calculated by time-dependent density functional theory (B3LYP) within the Tamm-Dancoff approximation. Bulk solvent effects in DMSO were taken into account by the CPCM solvation model. Particular long-wavelength absorption and emission ( abs ~540 nm,  F ~670) is found for derivatives containing an amino group in position 6 and an ether oxygen at C7 (compound 3). In contrast, considerably shorter wavelength absorption and fluorescence ( abs ~440 nm,  F ~530) is calculated for the isomeric compound 4. Both long wave length absorption and emission and in addition sufficiently large oscillator strengths are predicted for the quinoxaline derivative 5 containing amino groups at C6 and C7.