ChemInform Abstract: IMPROVEMENT OF THE APPLICABILITY OF TAFT-KAMLET SOLVENT POLARITY PARAMETERS TO CHEMICAL REACTIVITY

The empirical solvent polarity parameters ENR and ET for the solvatochromic compounds Nile Red (1) and pyridinium-N-phenoxide betaine (2), respectively, have been determined as a function of composition for water+t -butyl alcohol and water+t-butylamine binary mixtures, over the whole composition range at 298 K. For both systems the two parameters vary with composition in a strongly non-linear fashion, and the polarity of the mixture decreases with increasing proportion of the organic cosolvent. The non-linear variation of the polarity parameters is attributed to water-cosolvent hydrophobic interactions at low cosolvent contents, and hydrogen-bonding interactions at higher cosolvent contents. Permittivity and refractive index have also been measured at 298 K for both systems, and both properties are strongly non-linear functions of composition.

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Quantum Chemistry of Cocaine and its Isomers I: Energetics, Reactivity and Solvation

South African Journal of Chemistry ◽

10.17159/0379-4350/2021/v75a3 ◽

2021 ◽

Vol 75 ◽

Author(s):

Safa Ben Amara ◽

Thorsten Koslowski ◽

Ali Zaidi

Keyword(s):

Dipole Moment ◽

Solvent Effect ◽

Density Functional ◽

Chemical Reactivity ◽

Theoretical Perspective ◽

Solvent Polarity ◽

Stable Conformation ◽

Functional Theory ◽

Implicit Solvents ◽

The Rich

ABSTRACT We investigate the rich stereochemistry of cocaine and its diastereoisomers from a theoretical perspective using density functional theory. The relative stability of the eight considered isomers is discussed, and a comparison of the corresponding internal coordinates is given. Our results reveal that the S-pseudococaine isomer is the most stable conformation, whereas the natural occurring isomer (R-cocaine) lies higher in energy. The different isomers' chemical reactivity is discussed based on the calculation of the hardness, softness, electrophilicity and dipole moment. It was found that the dipole moment varies over a broad range from 0.65 to 4.60 D, whereas the other properties are slightly modified. The solvent effect on the energy stability of the cocaine isomers was studied by considering chloroform, dimethyl-sulfoxide (DMSO) and water as implicit solvents. Our calculations show that the different isomers' energy order and their energy gaps are slightly modified due to solvent effects. However, in all cases, the S-pseudococaine remains the most stable isomer. However, the dipole moment and the chemical reactivity of the cocaine isomers increase with the solvent polarity. Keywords: Cocaine isomers,DFT, stability, solvent effect, chemical reactivity.

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Synthesis photophysical studies of some furfurylnitrones: high-ly selective chemosensors for Zn2+ and DFT studies

International Journal of Advanced Chemistry ◽

10.14419/ijac.v6i1.8896 ◽

2018 ◽

Vol 6 (1) ◽

pp. 37 ◽

Cited By ~ 3

Author(s):

Ezhumalai Dhineshkumar ◽

Mathivanan Iyappan ◽

Rajendran Ganapathi ◽

Chinnadurai Anbuselvan

Keyword(s):

Molecular Structure ◽

Solvent Polarity ◽

Zinc Ion ◽

Dft Studies ◽

Fluorescence Sensing ◽

1H And 13C Nmr ◽

Ft Ir ◽

Photophysical Studies ◽

Polarity Parameters ◽

Electronic Ground

New aldonitrones(1-4) were synthesized and characterized by UV-vis, fluorescence, FT-IR, 1H and 13C NMR spectral analyses. The absorption and fluorescence sensing spectra of the compounds were precise in different polarity of solvent. The solvent polarity parameters have been used to propose a quantitative approach towards the reliable stability of the electronic ground and excited state species. Photochemical behaviors of the compounds were analyzed by applying multi-linear correlation methods. The characterized compounds 1-4 show a chemosensing detection of zinc ion in aqueous solution. Besides, the fluorescence spectroscopic responses were reversible when the Zn2+chelating reagentEDTANa2.The phenomenon proves that these compounds to show a sensitivity “on-off” sensor for Zn2+.Further, to recognize the molecular structure, electronic and optical properties and DFT calculations of the molecules were formed.

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