Conformal transitions of the laurdan molecule in the absorption and fluorescence spectra

Abstract

535.37 V. Ya. Artyukhov, and B. V. Korolev The fluorescent probe molecule -laurdan (6-dodekanoil-2-dimetilamin naphthalene) -is investigated by experimental and quantum-chemical methods. The influence of the structure non-rigidity on the dipole moments, arrangement of energy levels, and distribution of charges in the laurdan molecule is studied. An optimized structure is obtained and analyzed by the molecular dynamics method. Several structures with different rotation angles of the dimethylamino group are investigated, for which energy, oscillator forces, and nature of electron states are calculated. Fluorescence spectra of the laurdan molecule in an inert solvent are interpreted. Centers of possible interaction of the molecule with a proton-donor solvent are established. Rate constants of radiative and nonradiative processes and quantum fluorescence yields of the examined probe are calculated.

Complementary Fluorescence Emission and Second Harmonic Spectra Improve Bilayer Characterization

“…The red line in protic polar solvents might therefore be from a planar conformation. The nonplanar conformation, responsible for the blue line, interacts through carbon atoms as well as suggested by other authors [24]. Alcohols are known to exist in nanostructured polar and nonpolar domains; exhibiting nonpolar and polar character that can give rise to different interactions with Laurdan, and thus to multiline spectra [25].…”

“…6 that red lines of all solvents form a class that share some common feature as do the blue lines. Experiments and computational calculations have shown that the higher and lower wavenumber emissions observed in hexane are from nonplanar and planar conformations of Laurdan respectively [24]. In protic polar solvents, Laurdan in planar conformation was shown to interact with the solvent molecule only through its carbonyl oxygen [24].…”

“…Experiments and computational calculations have shown that the higher and lower wavenumber emissions observed in hexane are from nonplanar and planar conformations of Laurdan respectively [24]. In protic polar solvents, Laurdan in planar conformation was shown to interact with the solvent molecule only through its carbonyl oxygen [24]. Laurdan's ability to accept hydrogen bonds was suggested to be responsible for a red shift that increased with the proportion of protic polar component in mixed protic and aprotic polar solvents [4].…”