scholarly journals Features of the Electronic Structure of Excited Quadrupolar Molecules in Non-Polar Solvents

2021 ◽  
pp. 68-84
Author(s):  
Nickolay Siplivy ◽  
◽  
Anatoly Ivanov ◽  
Keyword(s):  
Dipole Moment ◽  
Molecular Electronics ◽  
Optical Excitation ◽  
Broken Symmetry ◽  
Electronic Subsystem ◽  
Polar Solvents ◽  
Orientational Polarization ◽  
Nonpolar Solvents ◽  
Solvent Polarization ◽  
Antisymmetric Vibrations

Interactions of the electronic subsystem of the quadrupolar fluorophore with intramolecular highfrequency antisymmetric vibrations and solvent polarization are responsible for charge transfer symmetry breaking (SB), which is observed after optical excitation of such molecules in polar solvents. It is known that although these two interactions are mathematically described in similar ways, only the interaction of the fluorophore with solvent orientational polarization can create a state with broken symmetry if this interaction is strong enough. Nevertheless, the interaction of a quadrupolar fluorophore with intramolecular highfrequency antisymmetric vibrations in nonpolar solvents leads to a considerable reconstruction of the electronic subsystem. The analysis of the excited state of quadrupolar molecules in nonpolar solvents performed in this study reveals that such molecules can behave like quantum twostate systems, that is, as a quasispin s = 1/2, having an electric dipole moment instead of a magnetic one. This feature of excited quadrupolar molecules may be of interest to emerging technologies of molecular electronics.

scholarly journals Regeneration of Spent Lubricant Refining Clays by Solvent Extraction

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Yan-zhen Wang ◽  
Hai-long Xu ◽  
Li Gao ◽  
Meng-meng Yan ◽  
Hong-ling Duan ◽  
...  
Keyword(s):  
Solvent Extraction ◽  
Petroleum Ether ◽  
Oil Recovery ◽  
Oil Refining ◽  
Lubricating Oil ◽  
Polar Solvents ◽  
Base Oil ◽  
Nonpolar Solvents ◽  
Total Oil ◽  
Storage Times

Step-by-step solvent extraction was used to regenerate spent clay by recovering the adsorbed oil in lubricating oil refining clay. Several polar and nonpolar solvents were tested, and petroleum ether (90–120°C) and ethanol (95 v%) were selected as the nonpolar and polar solvents, respectively. The spent clay was first extracted using petroleum ether (90–120°C) to obtain ideal oil and then extracted with a mixed solvent of petroleum ether (90–120°C) and ethanol (95 v%) two or three times to obtain nonideal oil before being extracted with ethanol and water. Finally, the clay was dried at 130°C to obtain regenerated clay. The total oil recovery can be more than 99 wt% of the adsorbed oil. The recovered ideal oil can be used as lubricating base oil. Shorter storage times for spent clay produce better regeneration results. The regenerated clay can be reused to refine the lubricating base oils.

scholarly journals Effects of Solvent Polarity on Solvation Free Energy, Dipole Moment, Polarizability, Hyperpolarizability and Molecular Properties of Metronidazole

2016 ◽  
Vol 19 (1) ◽  
pp. 9-14 ◽  
Author(s):  
Mohammad Firoz Khan ◽  
Ridwan Bin Rashid ◽  
Md Yeunus Mian ◽  
Mohammad S Rahman ◽  
Mohammad A Rashid
Keyword(s):  
Free Energy ◽  
Dipole Moment ◽  
Gas Phase ◽  
Chemical Potential ◽  
Solvent Polarity ◽  
Solvation Free Energy ◽  
Molecular Properties ◽  
Chemical Hardness ◽  
Electrophilicity Index ◽  
Polar Solvents

A computational study of medium effect on solvation free energy, dipole moment, polarizability, hyperpolarizability and different molecular properties like chemical hardness & softness, chemical potential, electronegativity and electrophilicity index of metronidazole have been reported in this paper. Becke, 3-parameter, Lee-Yang-Parr (B3LYP) level of theory with 6-31G (d,p) basis set was applied for gas phase and solution. The effect of solvent polarity on solvation free energy, dipole moment, polarizability, hyperpolarizability and molecular properties were calculated by employing Solvation Model on Density (SMD). The solvation free energies and dipole moment of metronidazole were found to be increased in nonpolar to polar solvents. The dipole moment of metronidazole was higher in different solvent than that of the gas phase. Moreover, from non-polar to polar solvents the chemical potential, electronegativity and electrophilicity index were increased. On the other hand, opposite relation was found in the case of chemical hardness and softness. The results obtained in this study may lead to understand the stability and reactivity of metronidazole and the results will be of assistance to use the title molecule as reaction intermediates and pharmaceuticals.Bangladesh Pharmaceutical Journal 19(1): 9-14, 2016

Liquefaction Properties of Alanine Hydrosulfate Ionic Liquid on Pine

2014 ◽  
Vol 525 ◽  
pp. 177-180
Author(s):  
Jian Hua Huang ◽  
Hong Lu Xie ◽  
Guo Feng Zou
Keyword(s):  
Ionic Liquid ◽  
Fourier Transform ◽  
Sulfuric Acid ◽  
Orthogonal Experiment ◽  
Hydrogen Sulfate ◽  
Mass Ratio ◽  
Polar Solvents ◽  
Orthogonal Experiment Design ◽  
Nonpolar Solvents ◽  
Strong Acidity

Ionic liquid containing alanine cations and hydrogen sulfate was synthesized using alanine and sulfuric acid as materials. Fourier Transform Infrared Specctrometer was used to verify the final product. The results showed that the objective product was developed successfully. General properties of the final product were detected. The results showed that strong acidity, large viscosity, soluble in polar solvents and insoluble in nonpolar solvents were the products properties which were suitable for liquefying. The liquefaction rate of ionic liquid on pine was studied. Study the optimum liquefaction condition using the method of orthogonal experiment design. By stirring at 120°C for 2 hours using ionic liquid with the concentration of 80% and with the mass ratio of 30, liquefaction rate of ionic liquid on pine was high.

Détermination de propriétés diélectriques de substances polaires: conditions d'applicabilité de l'équation d'Omini

1982 ◽  
Vol 60 (18) ◽  
pp. 2398-2402
Author(s):  
Léo Dégrève ◽  
Paulo Roberto Brossi Pelissari ◽  
Maria Marcia Murta
Keyword(s):  
Dielectric Constant ◽  
Dipole Moment ◽  
Nonpolar Solvents

An equation which allows for the determination of the dipole moment and polarizability of polar substances via the dielectric constant of solutions of the substance in nonpolar solvents is tested using different solute–solvent pairs. The results indicate that this equation provides good values of the dipole moment and of the polarizability if the solvent is correctly chosen. [Journal translation]

Spectroscopic Studies of Dimethylamino Derivatives of Fluorene

2000 ◽  
Vol 55 (11-12) ◽  
pp. 902-908 ◽  
Author(s):  
J. Heldt ◽  
J. R. Heldt ◽  
T. Redzimski ◽  
H. Diehl ◽  
P. Schultz
Keyword(s):  
Dipole Moment ◽  
Excited State ◽  
Charge Transfer ◽  
Fluorescence Spectra ◽  
Intramolecular Charge Transfer ◽  
Stokes Shift ◽  
Spectroscopic Studies ◽  
Polar Solvents ◽  
Derivatives Of ◽  
Transfer State

Abstract 2-dimethylamino-9-fluorenol and 2-dimethylamino-9(4'dimethylamino)phenyl-9-fiuorenol in polar solvents in the excited state undergo conformation changes in which two fluorescent isomers are created. The isomers (in the local excited (LE) and charge transfer (CT) configuration) possess separate fluorescence bands, one appearing from the S1 (LE) state and the second from the intramolecular charge transfer state S1 (CT) of the neutral, aromatic molecule. Both bands show a solvatochromic effect. Using the method of the solvent induced Stokes shift of the absorption and fluorescence spectra the permanent dipole moment of the excited state of fluorene and its two derivatives have been determined. The dipole moment of the ground state and the Onsager cavity radius of the studied molecules were calculated with the Auestion Model 1 (AM1) program.

Molar Kerr constants and solute polarizability anisotropies of ammonia, trimethylamine, trimethylamine oxide and 1,4-Diazabicyclo[2,2,2]octane

1977 ◽  
Vol 30 (7) ◽  
pp. 1411 ◽  
Author(s):  
RS Armstrong ◽  
MJ Aroney ◽  
KE Calderbank ◽  
RK Pierens
Keyword(s):  
Dipole Moment ◽  
Electric Dipole ◽  
Dipole Moments ◽  
Polar Solvents ◽  
Effective Polarizability ◽  
Electric Dipole Moments ◽  
Trimethylamine Oxide ◽  
Solute Interactions ◽  
Kerr Constants

Electric dipole moments and molar Kerr constants are reported for ammonia, trimethylamine, trimethylamine oxide, 1,4- diazabicyclo[2,2,2]octane and its monohydrate in non-polar solvents. The dipole moment now found for 1,4-diazabicyclo[2,2,2]octane differs substantially from previously recorded values. Effective polarizability anisotropies are derived for each of the anhydrous molecules and for the N-H and N-C bonds. The effect of solute interactions with benzene is explored.

scholarly journals Isomerization and Properties of Isomers of Carbocyanine Dyes

Sci ◽  
2018 ◽  
Vol 1 (1) ◽  
pp. 5 ◽  
Author(s):  
Pavel Pronkin ◽  
Alexander Tatikolov
Keyword(s):  
Phenyl Ring ◽  
Steric Effect ◽  
Cyanine Dyes ◽  
Information Storage ◽  
Polymethine Chain ◽  
Trans Isomers ◽  
Trans Form ◽  
Polar Solvents ◽  
Carbocyanine Dyes ◽  
Nonpolar Solvents

One of the important features of polymethine (cyanine) dyes is isomerization around one of C–C bonds of the polymethine chain. In this review, spectral properties of the isomers, photoisomerization and thermal back isomerization of carbocyanine dyes, mostly meso-substituted carbocyanine dyes, are considered. meso-Alkyl-substituted thiacarbocyanine dyes are present in polar solvents mainly as cis isomers and, hence, exhibit no photoisomerization, whereas in nonpolar solvents, in which the dyes are in the trans form, photoisomerization takes place. In contrast, the meso-substituted dyes 3,3′-dimethyl-9-phenylthiacarbocyanine and 3,3′-diethyl-9-(2-hydroxy-4-methoxyphenyl)thiacarbocyanine occur as trans isomers and exhibit photoisomerization in both polar and nonpolar solvents. The behavior of these dyes may be explained by the fact that the phenyl ring of the substituent in their molecules can be twisted at some angle, removing the substituent from the plane of the molecule and reducing its steric effect on the conformation of the trans isomer. In some cases, photoisomerization of cis isomers of meso-substituted carbocyanine dyes is also observed (for some meso-alkyl-substituted dyes complexed with DNA and chondroitin-4-sulfate; for 3,3′-diethyl-9-methoxythiacarbocyanine in moderate polarity solvents). The cycle photoisomerization–thermal back isomerization of cyanine dyes can be used in various systems of information storage and deserves further investigation using modern research methods.

A novel photorearrangement of 1,3-diketonatoborinate: a photoinduced intramolecular alkylation on a conjugated carbonyl system

1999 ◽  
Vol 77 (8) ◽  
pp. 1374-1383 ◽  
Author(s):  
Jun-ichi Ishiyama ◽  
Yuan L Chow
Keyword(s):  
Acetic Acid ◽  
Heavy Atom ◽  
High Yield ◽  
Triplet Excited State ◽  
Transition Band ◽  
Polar Solvents ◽  
Radical Oxidation ◽  
Nonpolar Solvents ◽  
Radical Processes ◽  
Atom Effect

Irradiation of borinates derived from 9-borabicyclo[3,3,1]nonane and 1,3-diketones at their π-π* transition band caused a rearrangement from their triplet excited state to give boronate intermediates that could be hydrolyzed to the corresponding aldols. The primary photolysis involves the scission of one of the B—C bonds followed by a 1,3- or 1,5-migration and the formation of a more stable B—O bond by radical pathways. The triplet state reaction was established by quenching and heavy atom effect experiments. The overall reaction pattern is an irreversible 1,2- or 1,4-addition of an alkyl-boron group to an α,β-conjugated ketone system by radical processes. Evidence showed that the non-isolated boronates also underwent secondary photoreactions followed by hydrolysis to afford enones corresponding to dehydration products of aldols; mechanisms are suggested for these secondary steps. The photoreaction was more facile in nonpolar solvents than in polar solvents; different solvents also gave different product compositions. In the presence of dilute acetic acid, the photolysis gave a high yield of aldols, suggesting a rapid acetolysis of the B—C bond in boronates to acetylborates. Under oxygen, the photolysis was complicated by radical oxidation to give totally different products.Key words: borinate photochemistry, charge transfer absorption, alkylborane addition, boronate intermediates, B—C bond homolytic scission

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