1622006-64-7

Upstream product

• 2525-19-1 1,2,6-trimethylpyridinium iodide 
• 123-08-0 4-hydroxy-benzaldehyde 
• 108-48-5 2,6-dimethylpyridine 

Relevant academic research and scientific papers

Solvent, structural, quantum chemical study and antioxidative activity of symmetrical 1-methyl-2,6-bis[2-(substituted phenyl)ethenyl]pyridinium iodides

15 symmetric 1-methyl-2,6-bis[2-(substituted phenyl)ethenyl]pyridinium iodides were synthesized in this work. Their structures were characterized using IR, 1H and 13C NMR, and UV–Vis spectroscopy. DFT calculations indicated that s-trans/s-trans conformation prevail in all compounds. The effects of specific and non-specific solvent–solute interactions on the UV–Vis absorption maxima shifts were evaluated using linear solvation-free energy relationships (LSER), i.e., Kamlet–Taft and Catalán models. A linear free energy relationship (LFER) in the form of single substituent parameter equations (SSP) was used to postulate quantitative structure–property relations of substituent effect on NMR data. TD-DFT results showed dependence of electronic transition on the substituent effects. The push–pull character of these compounds was analyzed by differences in 13C chemical shift of the ethylenic double bond in 2- and 6-positions of cross-conjugated with pyridinum central ring. Also, the quotient of the occupations for the bonding π and anti-bonding π* orbitals of this bond was considered. Good correlations of the selected parameter between double bond lengths with π*/π and 13C chemical shift differences of the bridging group proved them to be adequate descriptor of push–pull character. Synthesized compounds were screened for the antioxidant activity, using 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical methods, and results demonstrated moderate antioxidant potential.

Solvatochromism of symmetrical 2,6-distyrylpyridines. An experimental and theoretical study

Seven symmetrical 2,6-distyrylpyridines, phenyl-substituted with hydrogen-bond donors, hydrogen-bond acceptors, halogens and hydrophobic moieties were synthesized and their spectroscopic characterization was done. Solvent effects on the absorption and fluorescence spectra were analyzed and quantified using the Kamlet-Taft and Catalán approach. The obtained results were rationalized by comparison of electrostatic potentials of the molecules in the ground and in excited state and by comparison of the frontier molecular orbitals (HOMO and LUMO), derived from quantum-mechanical calculations (HF, DFT, MP2). Analysis of the results revealed an important influence of non-specific (dispersive) interactions on the solvatochromic behavior of the compounds. 1D and 2D NMR data, in silico obtained conformational assembly of the compound, and the NMR analysis of molecular flexibility in solution (NAMFIS), were used to estimate population of conformers and to deconvolute the UV-Vis spectrum of representative derivative; inferring that the conformational assembly is more complex than was assumed in so far published literature data for this class of compounds. Along with this, the emission spectra of the representative compounds were decomposed by the Multivariate Curve Resolution analysis.