Effect of dipole moment

Less clear is whether a different approach than that used with dielectric constant might be fruitful with dipole moment. A useful solvation algorithm does not seem to have emerged from studies of the effect of dipole moment on solvation energies, e.g. 

Young and Fitzgerald (1995) analyzed the effects of dipole moments on the hole mobilities of a series of aiylalkane, aiylamine, carbazole, hydrazone, pyrazoline, and oxadiazole molecules doped into a PC, PS, and as vapor-deposited glasses. The results agreed with earlier work of Sugiuchi et al. (1991). With the exception of the aiylalkane derivatives, the mobilities decreased in a near exponential manner with increasing dipole moment. 

IR A1/4 of CHsOD in many solvents, effect of dipole moment. 

The effect of dipole moment may be illustrated by a series of solubility ciurves for dipolar ions of different electric moments in 80% ethanol con ... 

Figure 3. Effect of dipole moment nx on gas-liquid critical lines (-)...

FIGURE 1.5 An effect of dipole moment on hydrophobicity of dicarbadodecaboranes 1,2-dicarba-c/oso-dodecaborane (orf/io-carborane) (1) 1,7-dicarba-c/oso-dodecaborane (mcfa-carborane) (2) 1,12-dicarba-cZoso-dodecaborane (para-carborane) (3). 

The additive effects of dipole moments near the chiral center and at the chiral center itself are demonstrated by a reference to Tables 4 and 5. The introduction of a large dipole moment in the form of a carbonyl function between the aromatic core and the chiral center to yield a number of alkanoyl-substituted (keto-) esters led to higher values than those of the corresponding ethers and esters, see Table 4 [50]. The presence of a second optically active group in the second terminal chain can also lead to additive effects and a still higher P, although y can be expected to be considerable [50]. A strong dependence of the observed Pg values on the number of carbon atoms in both terminal chains and the presence and... 

Experimental measurements of dipole moments give size but not direction We normally deduce the overall direction by examining the directions of individual bond dipoles With alkenes the basic question concerns the alkyl groups attached to C=C Does an alkyl group donate electrons to or withdraw electrons from a double bond d This question can be approached by comparing the effect of an alkyl group methyl for exam pie with other substituents... 

Using the Stark effect, the dipole moment of, for example, CH3F has been found to be... 

Of the five sets which were correlated with eq. (2), four gave significant correlations. Values of Pr are in the range 50 to 54, which indicates approximately equal contributions of the localized and delocalized effects. Thus, dipole moments of substituted acetylenes could be correlated successfully with the Up constants. 

Dipole Homents and Kerr Effect. - The structures of two conformers of ethyldifluorophosphane have been determined using a combination of dipole moments and microwave spectroscopy.227 Dipole moments have been used to study the different tuist angles of allenic phosphonates (81),228 and also to deduce the stereochemistry of 1,3,2,5-dioxaboraphosphorinane.22 ... 

Pople, J. A., and M. Gordon. 1967. Molecular Orbital Theory of the Electronic Structure of Organic Compounds. I. Substituent Effects and Dipole Moments. J. Am. Chem. Soc. 89, 4253-4261. 

These interactions (dd, di, ii) are a function of dipole moment and polarizability. It has been shown that the dipole moment cannot be replaced entirely by the use of electrical effect substituent constants as parameters52. This is because the dipole moment has no sign. Either an overall electron donor group or an overall electron acceptor group may have the same value of /x. It has also been shown that the bond moment rather than the molecular dipole moment is the parameter of choice. The dipole moments of MeX and PhX were taken as measures of the bond moments of substituents bonded to sp3- and sp2-hybridized carbon atoms, respectively, of a skeletal group. Application to substituents bonded to sp-hybridized carbon atoms should require a set of dipole moments for substituted ethynes. 

Here we focus on the effect of dipolar dispersion laws for high-frequency collective vibrations on the shift and width of their spectral line, with surface molecules inclined at an arbitrary angle 6 to the surface-normal direction. For definiteness, we consider the case of a triangular lattice and the ferroelectric ordering of dipole moments inherent in this lattice type.56,109 Lateral interactions of dynamic dipole moments p = pe (e = (sin os, sin6fcin , cos )) corresponding to collective vibrations on a simple two-dimensional lattice of adsorbed molecules cause these vibrations to collectivize in accordance with the dispersion law 121... 

Relative contribution of each of these structures differs significantly and is determined by internal structural characteristics of the nitrones and by the influence of external factors, such as changes in polarity of solvent, formation of a hydrogen bond, and complexation and protonation. Changes in the electronic stmcture of nitrones, effected by any of these factors, which are manifested in the changes of physicochemical properties and spectral characteristics, can be explained, qualitatively, by analyzing the relative contribution of A-G structures. On the basis of a vector analysis of dipole moments of two series of nitrones (355), a quantum-chemical computation of ab initio molecular orbitals of the model nitrone CH2=N(H)0 and its tautomers, and methyl derivatives (356), it has been established that the bond in nitrones between C and N atoms is almost... 

The solute/solvent interaction is, however, a much more complex physical effect than the simple creation of dipole moments in solvent molecules and their subsequent reorientation operated by the charges of the salts forming the solute. In fact, one can consider ... 

Abstract Although the electronic structure and the electrical properties of molecules in first approximation are independent of isotope substitution, small differences do exist. These are usually due to the isotopic differences which occur on vibrational averaging. Vibrational amplitude effects are important when considering isotope effects on dipole moments, polarizability, NMR chemical shifts, molar volumes, and fine structure in electron spin resonance, all properties which must be averaged over vibrational motion. 

The dipole moment is a fundamental property of a molecule (or any dipole unit) in which two opposite charges are separated by a distance . This entity is commonly measured in debye units (symbolized by D), equal to 3.33564 X 10 coulomb-meters, in SI units). Since the net dipole moment of a molecule is equal to the vectorial sum of the individual bond moments, the dipole moment provides valuable information on the structure and electrical properties of that molecule. The dipole moment can be determined by use of the Debye equation for total polarization. Examples of dipole moments (in the gas phase) are water (1.854 D), ammonia (1.471 D), nitromethane (3.46 D), imidazole (3.8 D), toluene (0.375 D), and pyrimidine (2.334 D). Even symmetrical molecules will have a small, but measurable dipole moment, due to centrifugal distortion effects. Methane " for example, has a value of about 5.4 X 10 D. 

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