K. Zachariasse - Academia.edu (original) (raw)

Papers by K. Zachariasse

Research paper thumbnail of Formation of Hetero-Excimers in Radical Ion Recombination Reactions

Luminescence of Crystals, Molecules, and Solutions, 1973

Research paper thumbnail of Intramolecular Excimers

Journal of Photochemistry, 1976

Research paper thumbnail of Determination of chemiluminescence quantum yields of radical ion reactions

Chemical Physics Letters, 1971

Research paper thumbnail of Direct hetero-excimer formation from radical ions

Chemical Physics Letters, 1971

Research paper thumbnail of Intramolecular excimer formation with non-planar molecules: 1,3-dibiphenylpropane. Kinetic and thermodynamic results

Chemical Physics Letters, 1978

Research paper thumbnail of Dimerization of porphyrins in highly dilute solution at low temperature and in monomolecular layers

Chemical Physics Letters, 1973

Research paper thumbnail of Investigation of human erythrocyte ghost membranes with intramolecular excimer probes

Biochimica et Biophysica Acta (BBA) - Biomembranes, 1982

Human erythrocyte ghost membranes have been investigated using two intramolecular excimer probes,... more Human erythrocyte ghost membranes have been investigated using two intramolecular excimer probes, di(1-pyrenyl)propane and di(1-pyrenylmethyl) ether. Values for the viscosity of the direct probe environment in the ghost membranes range from 76 cP at 37 degrees C to 570 cP at 5 degrees C, as reported for di(1-pyrenyl(propane, with liquid paraffin as the reference solvent. For the activation energy of the excimer formation process, determined here mainly by the viscosity of the medium, a value of 37 kJ/mol is obtained. The other probe molecule reports a higher local viscosity, 133 cP at 37 degrees C, as well as a higher activation energy of excimer formation, 54 kJ/mol. Neither thermotropic phase transitions nor temperature hysteresis effects are observed within the temperature range (0 to 40 degrees C) studied. From the vibrational structure of the fluorescence spectrum of di(1-pyrenylmethyl) ether, a polarity of the probe environment close to that of hexanol (epsilon - 13.3) results for the erythrocyte ghost membranes. The polarity measured in egg phosphatidylcholine membranes and in multibilayers of dimyristoylphosphatidylcholine is slightly larger, comparable to that of butanol (epsilon = 17.5), whereas a polarity comparable to that of methanol (epsilon = 32.7) is observed for aqueous micellar solutions of sodium dodecyl sulphate. Further, from the wavelength shifts in the absorption spectrum of di(1-pyrenyl)propane and di(1-pyrenylmethyl) ether, the polarizability of the probe surroundings can be determined, leading to a surprisingly high value for the apparent refractive index. This is attributed to a high local density of the direct environment of the probe, for which a location between the membrane/water interface and the unpolar bilayer mid-plane is deduced.

Research paper thumbnail of Intramolecular charge transfer in the excited state. Kinetics and configurational changes

Journal of Photochemistry and Photobiology A: Chemistry, 1996

Research paper thumbnail of Formation of Hetero-Excimers in Radical Ion Recombination Reactions

Luminescence of Crystals, Molecules, and Solutions, 1973

Research paper thumbnail of Intramolecular Excimers

Journal of Photochemistry, 1976

Research paper thumbnail of Determination of chemiluminescence quantum yields of radical ion reactions

Chemical Physics Letters, 1971

Research paper thumbnail of Direct hetero-excimer formation from radical ions

Chemical Physics Letters, 1971

Research paper thumbnail of Intramolecular excimer formation with non-planar molecules: 1,3-dibiphenylpropane. Kinetic and thermodynamic results

Chemical Physics Letters, 1978

Research paper thumbnail of Dimerization of porphyrins in highly dilute solution at low temperature and in monomolecular layers

Chemical Physics Letters, 1973

Research paper thumbnail of Investigation of human erythrocyte ghost membranes with intramolecular excimer probes

Biochimica et Biophysica Acta (BBA) - Biomembranes, 1982

Human erythrocyte ghost membranes have been investigated using two intramolecular excimer probes,... more Human erythrocyte ghost membranes have been investigated using two intramolecular excimer probes, di(1-pyrenyl)propane and di(1-pyrenylmethyl) ether. Values for the viscosity of the direct probe environment in the ghost membranes range from 76 cP at 37 degrees C to 570 cP at 5 degrees C, as reported for di(1-pyrenyl(propane, with liquid paraffin as the reference solvent. For the activation energy of the excimer formation process, determined here mainly by the viscosity of the medium, a value of 37 kJ/mol is obtained. The other probe molecule reports a higher local viscosity, 133 cP at 37 degrees C, as well as a higher activation energy of excimer formation, 54 kJ/mol. Neither thermotropic phase transitions nor temperature hysteresis effects are observed within the temperature range (0 to 40 degrees C) studied. From the vibrational structure of the fluorescence spectrum of di(1-pyrenylmethyl) ether, a polarity of the probe environment close to that of hexanol (epsilon - 13.3) results for the erythrocyte ghost membranes. The polarity measured in egg phosphatidylcholine membranes and in multibilayers of dimyristoylphosphatidylcholine is slightly larger, comparable to that of butanol (epsilon = 17.5), whereas a polarity comparable to that of methanol (epsilon = 32.7) is observed for aqueous micellar solutions of sodium dodecyl sulphate. Further, from the wavelength shifts in the absorption spectrum of di(1-pyrenyl)propane and di(1-pyrenylmethyl) ether, the polarizability of the probe surroundings can be determined, leading to a surprisingly high value for the apparent refractive index. This is attributed to a high local density of the direct environment of the probe, for which a location between the membrane/water interface and the unpolar bilayer mid-plane is deduced.

Research paper thumbnail of Intramolecular charge transfer in the excited state. Kinetics and configurational changes

Journal of Photochemistry and Photobiology A: Chemistry, 1996