Today I read that Bent's Rule can be used to explain the inductive effect (I was reading the Consequences section of this Wikipedia article). If I understand it correctly, for a molecule CL3R, the more electronegative the substituents (denoted L) are, the more s character can be saved for the hybrid orbital that the C uses for the C-R bond. Higher s character for the hybrid orbital means lower energy, so when the C-R bond forms, the resulting molecular orbital has more electron density around the carbon. This means that the carbon withdraws electrons better, so the electron-withdrawing property of the substituents has been transmitted to the carbon.

However, when I originally learned about the inductive effect, I understood it through a Coulombic argument: the three electronegative substituents withdraw electrons from the carbon, creating a partial positive charge on the carbon, which gives it a better pull on the electrons in the C-R bond (in other words a higher electronegativity).

Are Bent's Rule and Coulomb's Law simply two separate ways of justifying the inductive effect, or should they be seen as working together to produce the inductive effect?

And of course, are these both just ways of simplifying the molecular orbital explanation of the inductive effect?



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