Jj. Aaron et al., ELECTRONIC SPECTRAL STUDIES AND DETERMINATION OF THE FIRST EXCITED SINGLET-STATE DIPOLE-MOMENTS OF NEW BENZO[A]PHENOTHIAZINE DERIVATIVES, Spectroscopy letters, 28(7), 1995, pp. 1111-1122
The room temperature (298 K) electronic absorption, and fluorescence e
xcitation and emission spectra of seven new, pharmacologically-importa
nt benzo[a]phenothiazines (12H-benzo[a]phenothiazine (1), 9-methyl-12H
-benzo[a] phenothiazine (2), 10-methyl-12H-benzo[a] phenothiazine (3),
11-methyl-12H-benzo[a]phenothiazine (4), 5-oxo-5H-benzo[a]phenothiazi
ne (5), 6-hydroxy-5oxo-5H-benzo[a]phenothiazine (6) and 6-methyl-5-oxo
-5H-benzo[a] phenothiazine (7).) were measured in several solvents of
different polarities and hydrogen bonding abilities. In combination wi
th the ground state dipole moments of these benzo[a]phenothiazines, th
e spectral data were used to determine their first excited singlet-sta
te dipole moments by means of the solvatochromic shift method. These e
xcited singlet-state dipole moments were found to be significantly hig
her (1.9 to 2.5 Debye units) than their ground-state counterparts.