0000000000609059
AUTHOR
Krystyna Rotkiewicz
Considerations on the dipole moment of molecules forming the twisted intramolecular charge transfer state
Several derivatives of dual-fluorescing dimethylaminobenzonitrile (DMABN) are compared regarding their ground and excited-state dipole moments extracted from electro-optical emission and solvatochromic measurements. The comparison includes bridged model compounds as well as compounds with different degrees of steric hindrance to planarity, as well as ester and carbazolyl derivatives. The results are discussed on the basis of the twisted intramolecular charge transfer (TICT) model, the most widely accepted model. They show that (i) the dipole moment of the A (TICT) state (long-wavelength band) shows only little solvent sensitivity (polarizability), (ii) this observed small dependence of the …
Substituent-induced coupling of the two lowest excited singlet states of 2-methoxy-derivatives of 4-(N,N-dimethylamino)- and 4-(N-methylamino)benzonitrileDedicated to Professor Dr Z. R. Grabowski and Professor Dr J. Wirz on the occasions of their 75th and 60th birthdays.
The title compounds both exhibit strong features of interaction of their two lowest excited states, but only one of them, the dimethylamino derivative, exhibits dual fluorescence. This is a direct indication that state interaction and dual fluorescence are not directly related.