Hydrogen bond formation between 4-(dimethylamino)pyridine and aliphatic alcohols.

The photophysics of 4-(dimethylamino)pyridine (DMAP) has been investigated in different solvents in the presence of aliphatic and fluorinated aliphatic alcohols, respectively. For most systems, consecutive two-step hydrogen-bonded complex formation is observed in the presence of alcohols. Equilibrium constants are determined from UV spectroscopic results for the formation of singly and doubly complexed species.

Kinetics and mechanism of the reactions of CH3CO and CH3C(O)CH2 radicals with O2. Low-pressure discharge flow experiments and quantum chemical computations.

The reactions CH(3)CO + O(2)--> products (1), CH(3)CO + O(2)--> OH +other products (1b) and CH(3)C(O)CH(2) + O(2)--> products (2) have been studied in isothermal discharge flow reactors with laser induced fluorescence monitoring of OH and CH(3)C(O)CH(2) radicals. The experiments have been performed at overall pressures between 1.33 and 10.

Hydrogen-bond formation between isoindolo[2,1-a]indol-6-one and aliphatic alcohols in n-hexane.

The spectroscopic, kinetic, and equilibrium properties of isoindolo[2,1-a]indol-6-one (I) were studied in n-hexane in the presence and absence of alcohols (X). Hydrogen-bonded-complex formation was found to occur between the alcohol and the ground state as well as the excited state of the I molecule. The spectra of I and its singly complexed derivative (IX) are similar; however, that of IX is red shifted.

Pressure dependence of the dual luminescence of twisting molecules. The case of substituted 2,3-naphthalimides.

The effect of high pressure (up to 5 kbar) has been studied for triacetin solutions of 2-phenyl-2,3-dihydro-1H-benzo[f]isoindole-1,3dione 1 (N-phenyl-2,3-naphthalimide) and its 3-fluorophenyl- (2), 4-carbethoxyphenyl(4) and 4-methoxyphenyl (5) derivatives which all show dual fluorescence. When the N-phenyl group is unsubstituted (compound 1) or substituted with electron-attracting groups (2 and 4), the increase of pressure over the solution decreases slightly the emission at the long-wavelengths (LW) and increases dramatically the intensity of the short-wavelength (SW) fluorescence. Plotting the logarithm of the SW/LW fluorescence quantum yield ratio for compounds, 1,2 and 4 versus the logarithm of the viscosity of the medium shows a substantial increase of this ratio which corresponds mainly to the increase of the SW emission intensity, the effect on the LW emission being only moderate.

Dual luminescence properties of differently benzo-fused N-phenylphenanthridinones.

The photophysics of some newly prepared N-arylphenanthridinone derivatives have been investigated. It has been demonstrated how the luminescence properties are influenced by the size of the aromatic ring system. It has been shown that the replacement of the phenyl group in N-phenyphenanthridinone (PP) by an alpha-naphthyl or beta-naphthyl group (alphaNP and betaNP, respectively), influences the fluorescence spectra very differently.