Fluorescence investigation of model compounds for light-emitting alternating copolymers in heterogeneous environments.
In this paper, the fluorescence spectra of the model compounds M(TPA-PPV) and M(TPA-PAV) of novel light-emitting alternating copolymers, were studied and the effect of KNO3 on the interaction between the model compounds and the ionic micelle-water interface was also investigated. The following is found: (i) the fluorescence changes of M(TPA-PPV) are related to the state of cetyltrimethylammonium bromide (CTAB) and sodium dodecyl sulfate (SDS) solution: (ii) an aggregated state can be formed in M(TPA-PAV) solution at low concentration of CTAB; (iii) higher concentrations of KNO3 may affect the interaction between the model compounds and the ionic micelle-water interface.
Photoinduced Intramolecular Charge Separation at the Repetition Units of Light‐Emitting Alternating Copolymers
Light-emitting nitrogen-containing poly(phenylene vinylene) PPV-related copolymers are synthesized by the weel-known Wittig-Horner reaction. The alternating copolymers have hole-transporting moieties such as triphenylamine (TPA) and conjugated aromatic units such as 1,4-phenylene, 1,4- or 1,5-naphthylene and 9, 10-anthrylene. The dipole moments within the repetition units of the copolymers in the excited state are estimated by measuring the solvent effect on absorption and fluorescense emission spectra, indicating that charge separation is present. The dipole moment values are in agreement with the electron affinities of aceptors, i.e. aromatic units. The evidence can help to elucidate the phtophysical behavior, particularly the fluorescence quantum efficiencies.
Impact of acetaldehyde‐ and pyruvic acid‐bound sulphur dioxide on wine lactic acid bacteria
Aims:  To investigate the impact of acetaldehyde‐ and pyruvic acid‐bound sulphur dioxide on wine lactic acid bacteria (LAB).