Constants and Dipole Moments

Some of the earliest relevant work in this area involved experimental studies of the dielectric relaxation times, polarizations, and dipole moments of the small molecules hexamethyldisiloxane, hexaethyldisiloxane, hexamethylcyclotrisiloxane, and octamethylcyclotetrasiloxane.  

Research on the corresponding polymers has focused almost exclusively on PDMS, but there has been some work on poly(diethylsiloxane). In the case of the PDMS, most studies have involved the linear chains, 225-235 gome the cyclics, and at least one cross-linked elastomer. Improvements in dielectric properties continue to be important goals in the case of the polysiloxanes.  

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Pulay P, FogarasI G, Pang F and Boggs J E 1979 Systematic ab initio gradient calculation of molecular geometries, force constants and dipole moment derivatives J. Am. Chem. Soc. 101 2550... 

The temperature in degrees Celsius at which the dielectric constant and dipole moment were measured is shown in this table in parentheses after the value. In some cases, the dipole moment was determined with the substance dissolved in a solvent, and the solvent used is also shown in parentheses after the temperature. 

Revised material for Section 5 includes the material on surface tension, viscosity, dielectric constant, and dipole moment for organic compounds. In order to include more data at several temperatures, the material has been divided into two separate tables. Material on surface tension and viscosity constitute the first table with 715 entries included is the temperature range of the liquid phase. Material on dielectric constant and dipole... 

Force Constants and Dipole-Moment Derivatives of Molecules from Perturbed Hartree-Fock Calculations I J. Gerratt and I. M. Mills Journal of Physical Chemistry 49 (1968) 1719... 

Correlations among solvent polarity scales, dielectric constant and dipole moment, and a means to reliable predictions of polarity scale values from current data. T. R. Griffiths and D. C. Pugh. Coord. Chem. Rev., 1979, 29,129-211 (130). 

A macroscopic model for regular air/solution interfaces has been proposed by Koczorowski et al 1 The model is based on the Helmholtz formula for dipole layers using macroscopic quantities such as dielectric constants and dipole moments. The model quantitatively reproduces Ax values [Eq. (37)], but it needs improvement to account for lateral interaction effects. 

Pulay, P., G. Fogarasi, F. Pang, and J. E. Boggs. 1979b. Systematic Ab Initio Gradient Calculation of Molecular Geometries, Force Constants, and Dipole Moment Derivatives. J. Am. Chem. Soc. 101, 2550-2560. 

Both the dielectric constant and dipole moment are comparable to those of water, indicating that HF is a good solvent for inorganic compounds, but many organic compounds are also soluble. In general, the fluorides of +1 metals are much more soluble than those of +2 or +3 metals. At 11 °C, the solubility of NaF is approximately 30 g per 100 g of liquid HF, that of MgF2 is only 0.025 g, and that of A1F3 is 0.002 g. 

Table 3 Ground state rotational constants and dipole moments for 1,2,4-trioxolanes and 1,2,4-trithiolane.

C3Hj C(HS. 03, liq, bp 70° at 0.5 mm, d 1.1361 at 20°, d 1-5132 at 20°. Can be prepd by ozonization of allylbenzene using the method of Harries (Ref 1 for oconization of org compds. A detailed description of its prepn is given by Ryffel(Ref 3). Briner et al (Ref 4) detd the following props of allylbenzeneozonide soly in benz, Raman spectra, UV absorption spectra, dielectric constants and dipole moments Note According to Dr H. Walter of PicArs this ozonide is an explosive... 

From these results it would therefore appear that the bulk electrostatic parameters of the solvent, e.g. dielectric constant and dipole moment, do not predict accurately the changes in redox potential that occur in different solvents. 

Ha et al.272 used an essentially DZ basis to calculate the force constants and dipole moment derivatives. 

Dielectric constants and dipole moments were taken from a table in Wikipedia, http //en. 

Continuum solvent models are normally parameterized with the solvent dielectric constant (but see the COSMO models, Chapter 8). First we note that dielectric constant and dipole moment are not in general well correlated from Chapter 8 ... 

No newer studies using microwave spectroscopy have been published for the parent system. The previous edition of CHEC(1984) should be consulted for ground state rotational constants and dipole moments. 

Krugh and Gold in an early study determined the rotational constants and dipole moment of the parent tetrazole by means of microwave spectroscopy in the gas phase A 10667.3, B 10310.9, C 5240.4 MHz, dipole moment 2.19 D <1974JSP423>. The results of calculations carried out by Fausto and co-workers using the B3LYP/6-31G method are only consistent with the data for the 277-tautomer of tetrazole confirming the prevalence of exactly this form of the compound in the gas phase <2001PCP3541>. 

Table 1 Geometries, rotational constants, and dipole moments of 1,2,5- and 1,3,4-selenodiazoles 3 and 4a...

TABLE 2-1 Comparison of Equations Relating Dielectric Constant and Dipole Moment... 

Dielectric constant and dipole moment do not incretise together. (See Table 2-II.)... 

Considerable progress has been made in trying to achieve an understanding of the molecular vibrations of cyclopropane and its derivatives, and it should be possible to bring all of these data together to obtain a detailed picture of how changes in structure affect force constants, interaction constants and dipole moment derivatives. 

Values of molar Kerr constants and dipole moments of nitrogen azoles and their complexes with phenols have been obtained. " These complexes are formed by an intermolecular hydrogen bond between the pyridine-type nitrogen of the azole and the phenolic proton. " The use of dipole moments in conformational studies has shown that A-aryl- and C-aryl- and A-furyl- and C-furyl imidazoles (and benzimidazoles) are nonplanar, but l-(a-furyl)-4,5-diphenylimidazoles do have a planar bicyclic fragment. The dipole moments and conformations of azolides (A-acylazoles) have been studied. In the 1-arylimidazoles the dipole is toward the aryl group. In 4,5-di-t-butylimidazole the molecule is essentially planar, but the C-4—C-5 bond is slightly stretched. Among other imidazole derivatives which have been studied by X-ray are histidine hydrochloride, 4-acetyl-amino - 2 - bromo - 5 - isopropyl -1 - methylimidazole, 4- acetyl - 5 - methyl - 2 -phenylimidazole, and imidazole-4-acetic acid hydrochloride. 

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