Solvatochromic study of excited state dipole moments of some biologically active indoles and tryptamines

• Published in: Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy Vol. 66; no. 1; pp. 171 - 176
• Main Authors: Sharma, Neera, Jain, Sapan K., Rastogi, Ramesh C.
• Format: Journal Article
• Language: English
• Published: England Elsevier B.V 2007
• Subjects: Dipole moment; Indoles - chemistry; Models, Chemical; PM3 method; Solvatochromic shift method; Solvents; Spectrometry, Fluorescence; Tryptamines - chemistry; Solvatochromic shift method; PM3 method; Dipole moment
• ISSN: 1386-1425
• DOI: 10.1016/j.saa.2006.02.039

Absorption and fluorescence spectra of some biologically active indole and tryptamine derivatives have been recorded at room temperature in solvents of different polarities. The interest in the photophysical properties of these molecules arises mainly from their utility in medicinal chemistry as neurotransmitter and hallucination/hallucinic agents. Excited-state dipole moments of these molecules have been estimated from solvent-dependent Stokes shift data using a solvatochromic method based on a microscopic solvent polarity parameter ( E T N ) . All indoles show a substantial increase in the dipole moment upon excitation to the emitting state. These results are generally consistent with the Parametric Method 3 (PM3) calculations, and are found to be quite reliable in view of the fact that the correlation of the solvatochromic Stokes shifts with the microscopic solvent polarity parameter ( E T N ) is superior to that obtained using bulk solvent polarity functions.