Issue 19, 1998

Semiempirical studies of solvent effects on the intramolecular charge transfer of the fluorescence probe PRODAN

Abstract

The organic chromophore 6-propanoyl-2-(N,N-dimethylamino)naphthalene (PRODAN) is widely used in biochemistry as an efficient fluorescence probe, due to its significant Stokes shift in polar solvents. The nature of the emissive states has not yet been established despite detailed experimental and theoretical investigations. The strong solvent dependence of PRODAN fluorescence requires a quantum mechanical study with explicit consideration of solvent effects. The excited-state properties of PRODAN have been investigated by means of the self-consistent reaction field (SCRF) method in combination with the semiempirical AM1 Hamiltonian. The geometrically unchanged planar conformation and the rotation of the dimethylamino (N) and the propanoyl (O) groups have been explored. Both geometrical relaxation pathways yield a highly polar twisted intramolecular charge-transfer state, the N-TICT and O-TICT states, respectively. These states are energetically stabilised in a polar environment at perpendicular geometries and become the lowest excited state. Based on the calculations, the experimentally observed red-shifted fluorescence is assigned to an emission from the propanoyl TICT state, for which a significantly reduced rotational barrier is found. Agreement with experimental results in various solvents is excellent.

Article information

Article type
Paper

J. Chem. Soc., Faraday Trans., 1998,94, 2923-2927

Semiempirical studies of solvent effects on the intramolecular charge transfer of the fluorescence probe PRODAN

A. Parusel, J. Chem. Soc., Faraday Trans., 1998, 94, 2923 DOI: 10.1039/A804841J

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Spotlight

Advertisements