Synthesis and characterization of new dual stimuli-responsive bisazobenzene derivatives

“New bisazobenzene derivatives with remarkable and reversible response to optical and chemical stimuli were synthetized and characterized”.

Photophysical behavior of some aromatic poly(1,3,4-oxadiazole-ether)s derivatives

The change in electronic absorption and emission spectra of two fluorinated poly(1,3,4-oxadiazole-ether)s in neat and binary solvent mixtures has been studied. The optical properties, absorption and photoluminescence of these polymers were investigated in solution and in solid state. The results were discussed as a function of solvent nature, excitation wavelength and local solvent composition, X2. The Catalan solvent scale was used for describing the solvatochromic shifts of the absorption and emission bands. The following binary solvent mixtures were used: chloroform-N,N'-dimethylformamide (CHCl3-DMF), chloroform-dimethyl sulfoxide (CHCl3-DMSO), and dimethylformamide-dimethyl sulfoxide (DMF-DMSO) and the influence of their composition on the absorption and emission maxima has been analyzed. The preferential solvation parameters such as local mole fraction (X2(L)), excess function (δs2) and preferential solvation constant (KPS) were determined.

Solvatochromic effects in the UV/vis absorption spectra of some pyridazinium ylides

Solvatochromic behavior of some carbanion monosubstituted and disubstituted pyridazinium ylides was studied experimentally in various polar and nonpolar solvents. Different solvent parameters, such as microscopic solvent polarity, E(T)(30), the Kamlet-Taft and the Catalan parameters have been used for describing the solute-solvent interactions and solvatochromic shifts of the visible intramolecular charge transfer (ICT) absorption band of pyridazinium ylides. It is found that the solute hydrogen bond donating ability and dipolarity/polarizability play an important role in the description of the pronounced solvatochromism in the studied solutions. The Catalan solvent scales are found to be the most suitable for describing the solvatochromic shifts.