Inductive effect Electronegativity

Are there any inductive effects (electronegative atoms or alkyl groups) that stabilize or destabilize any of the conjugate bases ... 

The proton NMR of the aldehyde hydrogen appears in the region of 5 = 9-10. This high shift is due to the inductive effect (electronegative... 

Inductive Effects Electronegative substituents increase the n(Si) - 3p(Si) transition energy and thus induce a blue-shift. The opposite is true for electropositive substituents. 

In contrast to the claim (10) that the ECW model "disguises the relationship between reactivity and periodic elemental properties", elementary application of frontier molecular orbital theory (H) can be used to understand the trends. Using qualitative trends in ionization energies, inductive effects, electronegativities and partial charge/size ratios, one can estimate trends in the HOMO-LUMO separation of the donor and acceptor. Increasing the separation decreases the covalent and increases the electrostatic nature of the interaction. Decreasing the separation has the opposite effect. Trends in the reported acid and base parameters as well as in the Ey E0 and C C0 products can be understood in this way. 

The inductive effect electronegative atoms adjacent to the charge will stabilize... 

C—D... N hydrogen bonding. Discuss the results in the Table on the basis of inductive effects (electronegativities) of the Group IV elements and of their capacity to form (p—d)n bonds with N, 0 or S. How is the extent of 7r-bonding reflected in the structures of the compounds. ... 

If both substituents on a C=0 bond are carbon or heavier atoms and bond angles are normal ( 120 ") then carbonyl frequency shifts can be related directly to mesomeric and inductive effects which account for the change in force constants of C=0 bonds and substituent single bonds. In the inductive effect, electronegative substituents (like Cl) raise C==0 frequencies by reducing the weight of carbonyl bond weakening resonance forms... 

The polarizing influence of an electronegative atom decreases with the number of inteiwening rr-bonds. This is called the inductive effect and is indicated in Figure 3-6b by a progression of 6 symbols, (t is generally accepted that the inductive effect is attenuated by a factor of 2-3 by each intervening bond. The inductive ctlcct is not... 

Previous studies with a variety of datasets had shown the importance of charge distribution, of inductive effect), of r-electronegativity, resonance effect), and of effective polarizability, aeffi polarizability effect) for details on these methods see Section 7.1). All four of these descriptors on all three carbon atoms were calculated. However, in the final study, a reduced set of descriptors, shown in Table 3-4, was chosen that was obtained both by statistical methods and by chemical intuition. 

To appreciate residual electronegativity as a measure of the inductive effect... 

The PEOE method leads to only partial equalization of orbital electronegativities. Thus, each atom of a molecule retains, on the basis of Eq. (12), a residual electronegativity that measures its potential to attract further electrons. It has been shown that the values of residual electronegativities can be taken as a quantitative measure of the inductive effect [35]. 

Once amines that also cany heteroatoms were included in the study, a dataset of 80 proton affinities was obtained. For those alkyl amines the inductive effect as quantified by residual electronegativity had also to be taken into account, A simple... 

Residual electronegativity values obtained by the PEOE method are useful quantitative measures of the inductive effect. 

Inductive effects depend on the electronegativity of the substituent and the num ber of bonds between it and the affected site As the number of bonds increases the inductive effect decreases... 

Electron Delocalization in the Conjugate Base With a of —1 4 nitnc acid is almost completely ionized m water If we look at the Lewis structure of nitric acid m light of what we have said about inductive effects we can see why The N atom m nitric acid IS not only electronegative m its own right but bears a formal charge of +1 which enhances its ability to attract electrons away from the —OH group... 

The strength of an acid depends on the atom to which the proton is bonded The two mam factors are the strength of the H—X bond and the electronegativity of X Bond strength is more important for atoms m the same group of the periodic table electronegativity is more important for atoms m the same row Electronegative atoms elsewhere m the molecule can increase the acidity by inductive effects... 

The decreased shielding caused by electronegative substituents is primarily an inductive effect and like other inductive effects falls off rapidly as the number of bonds between the substituent and the proton increases Compare the chemical shifts of the pro tons m propane and 1 mtropropane... 

Closely related to the inductive effect and operating in the same direction is the field effect In the field effect the electronegativity of a substituent is communicated not by successive polarization of bonds but via the medium usually the solvent A substituent m a molecule polarizes surrounding solvent molecules and this polarization is transmit ted through other solvent molecules to the remote site... 

Steric and inductive effects determine the rate of formation of the pentacovalent siUcon reaction complex. In alkaline hydrolysis, replacement of a hydrogen by alkyl groups, which have lower electronegativity and greater steric requirements, leads to slower hydrolysis rates. Replacement of alkyl groups with bulkier alkyl substituents has the same effect. Reaction rates decrease according to ... 

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