Dipole Moments and the Stereochemistry of Organic Compounds

Минкин, В. И.; Osipov, O. A.; Zhdanov, Yurii A.; Vaughan, Worth E.

doi:10.1007/978-1-4684-1770-8_4

Cited by 9 publications

(13 citation statements)

References 104 publications

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“…The general rule of thumb in chemistry is that the more polar solvent stabilizes the more polar species. The dipole moment of DMSO is 3.9 D, while the same for acetonitrile is 3.4 D. 65 Obviously, the pyridinium-type cation 11 , in which the effective delocalization of the positive charge is possible throughout the acenaphthopyridine core and with the participation of dimethylamino groups, is more polar than cation 10 . It is natural that it is cation 11 that stabilizes the more polar medium DMSO- d 6 ( cf.…”

Section: Resultsmentioning

confidence: 99%

Synthesis, conformational stability and molecular structure of 4-aryl- and 4,5-diaryl-1,8-bis(dimethylamino)naphthalenes

et al. 2023

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Section: Resultsmentioning

confidence: 99%

Synthesis, conformational stability and molecular structure of 4-aryl- and 4,5-diaryl-1,8-bis(dimethylamino)naphthalenes

et al. 2023

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“…The magnitude of a dipole moment of O←N coordination chemical bonding including the contribution of three methyl groups bound to a nitrogen atom was estimated to be μ = 4.9 D with TMAO solutions in nonpolar solvents …”

Section: Discussionmentioning

confidence: 99%

“…Because the O←N group has an electric dipole moment, ca. ∼5 D, due to O←N coordinate chemical bonding much greater than that of ordinary organic compounds and a solvent, water, the rotational relaxation mode of individual DDAO molecules in spherical micelles is precisely detected at pH values higher than 7 by using the dielectric relaxation measurement. On the other hand, when the pH value is lower than 7 by adding HBr, HO−N + groups of protonated DDAO might form ion pairs with Br - in micelles as well as DTAB in aqueous solutions.…”

Section: Introductionmentioning

confidence: 99%

Dielectric Relaxation Behavior of Aqueous Dodecyldimethylamineoxide Solutions

and

Shikata

2001

Langmuir

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Dielectric relaxation behavior was examined for aqueous solutions of dodecyldimethylamineoxide (DDAO) in the range of concentration (c D) from 100 to 500 mM varying the average degree of protonation (〈α〉) by adding HBr. DDAO has an electric dipole moment due to an O←N coordination chemical bond on its headgroup, and the fraction of O←N is reduced by adding HBr, while that of HO−N+ increases. This process was detected as a change in dielectric spectra. Dielectric spectra for aqueous DDAO solutions had four types of relaxation modes. A fast relaxation time (τ1 ∼ 10-10 s) was essentially independent of c D, and the relaxation strength (Δε1) was proportional to c D at 〈α〉 = 0. Moreover, the magnitude of Δε1 decreased with 〈α〉; therefore, it was attributed to the rotational relaxation mode of O←N type headgroups in spherical micelles. A relaxation mode with c D-independent τ2 (∼10-9 s) possessed relaxation strength (Δε2) proportional to c D. Because Δε2 increased with 〈α〉 by adding HBr and the number of Br- entrapped in micelles increased with 〈α〉, the mode was assigned to the rotational relaxation mode of an ion pair formed between HO−N+ and Br- on the micellar surface. A relaxation mode with τ3 (∼10-8 s) at 〈α〉 > 0 was attributed to the rotational relaxation mode of intermolecular association particles formed between protonated and unprotonated DDAO molecules due to intermolecular forces such as hydrogen bonding. A slow mode with τ4 (∼10-7 s at 〈α〉 = 0) was assigned to the relaxation of a counterion distribution around spherical DDAO micelles. When 〈α〉 was higher than 0.5, dielectric behavior of aqueous DDAO solutions was essentially the same as that of aqueous solutions of cationic detergents. The addition of NaBr to aqueous DDAO solutions at 〈α〉 greater than 0.5 made a spherical micellar shape change into a spheroidal shape. This change in micellar shapes made dielectric relaxation spectra much broader.

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“…Zwitterionic compounds possess high solubility in water, and they still have bipolar structure keeping relatively long separation between two opposite charges even in aqueous solution. Thus, it is anticipated that zwitterions have considerably large dipole moments in an aqueous solution, e.g., greater than 10 D. However, reliable data and discussion on the dipole moments had not been reported for zwitterions and other polar solute molecules with relatively large dipole moments in solutions of polar solvents such as water . We do not have a general method to evaluate the magnitude of dipole moments for polar solutes in aqueous solutions, although well-known Debye's method − is very useful in dilute solutions of polar solutes in nonpolar media.…”

Section: Introductionmentioning

confidence: 97%

“…Thus, it is anticipated that zwitterions have considerably large dipole moments in an aqueous solution, e.g., greater than 10 D. However, reliable data and discussion on the dipole moments had not been reported for zwitterions and other polar solute molecules with relatively large dipole moments in solutions of polar solvents such as water . We do not have a general method to evaluate the magnitude of dipole moments for polar solutes in aqueous solutions, although well-known Debye's method − is very useful in dilute solutions of polar solutes in nonpolar media. Of course, it is important to establish a general method that can provide the precise value of dipole moments for polar solutes in solution of polar solvents through data obtained by conventional dielectric relaxation measurements.…”

Section: Introductionmentioning

confidence: 97%

Dielectric Relaxation Behavior of Glycine Betaine in Aqueous Solution

Shikata

2002

J. Phys. Chem. A

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Dielectric relaxation behavior of aqueous glycine betaine (N,N,N-trimethylglycine) (GB) solutions was examined as a function of frequency from 6.28 × 10 6 to 1.26 × 10 11 rad s -1 (1.00 × 10 6 to 20.0 × 10 9 Hz). Two kinds of relaxation modes were observed at frequencies of 1.25 × 10 11 and 2.5 × 10 10 rad s -1 . The fast relaxation mode of which strength decreases with increasing the concentration of GB corresponds to the rotational relaxation mode of the medium, water. The other mode has relaxation strength proportional to the concentration of GB and is attributed to the rotational relaxation mode of GB bearing hydrated water molecules. To evaluate the magnitude of dipole moment (µ) and the number of tightly hydrated water molecules (m) to GB in aqueous solution, an analytical model proposed previously was employed, then, the values, µ ∼ 8.0 D and m ) 2, were evaluated irrespective of the concentration of GB. On the other hand, ab initio quantum chemical calculations were carried out to determine the magnitude of µ for GB dihydrate as a model describing the state of GB in an aqueous solution. Agreement between the µ values obtained from experimental results and the calculation is reasonably good.

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Dipole Moments and the Stereochemistry of Organic Compounds

Cited by 9 publications

References 104 publications

Synthesis, conformational stability and molecular structure of 4-aryl- and 4,5-diaryl-1,8-bis(dimethylamino)naphthalenes

Synthesis, conformational stability and molecular structure of 4-aryl- and 4,5-diaryl-1,8-bis(dimethylamino)naphthalenes

Dielectric Relaxation Behavior of Aqueous Dodecyldimethylamineoxide Solutions

Dielectric Relaxation Behavior of Glycine Betaine in Aqueous Solution

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