Some features of how phenylated solvents affect the shift of the absorption and fluorescence spectra of solutions of 4-dimethylaminochalcone

A new version of the semiempirical theory of solvatochromic and solvatofluorochromic phenomena is used to quantitatively analyze the regularities of the joint influence of universal and specific intermolecular interactions on the shift of the absorption and emission spectra of solutions of 4-dimethylaminochalcone (DMC), which is widely used as a luminescence probe in modem biomedical studies, in phenylated solvents. It is established that the electric-dipole moment of the DMC molecule has a significantly greater effect (Delta mu(ge) approximate to 9 D) when the indicated solutions are optically excited in the region of the intramolecular-charge-transport band than when solvents of another chemical nature are used (Delta mu(ge) approximate to 7 D). The opinion is expressed and substantiated that these specific features are caused by the formation of weak donor-acceptor complexes in the test solutions, producing additional charge transfer from the molecule (or molecules) of the phenylated solvents to the DMC molecule. (c) 2007 Optical Society of America.