Timeline for Does inductive effect operate through pi bonds?
Current License: CC BY-SA 4.0
23 events
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| Nov 10, 2021 at 7:02 | comment | added | Alchimista | @Amadeus I think your second last comment although could be more elegantly formulated resume the situation. And now that you have changed double into pi in the title, even more. In a way one side of the C involved tends to "repel" electrons, while the other tend to "attract" them. This makes the unit involved a kind of stopper. But the physics is just buried, still at work. | |
| Nov 10, 2021 at 4:39 | comment | added | Amadeus | Creates more confusion than help but oh well | |
| Nov 10, 2021 at 4:38 | comment | added | Amadeus | For me the final answer then would be that induction, which is just shifting electron densities due to electrostatic attraction, happens just fine for both sigma and double bonds since the physics involved is the same and there's nothing special about the pi bonds position, but as total electron shifting has to be pretty much the same the induction gets dampened, distributed between the two bonds. Thus in effect it doesn't matter and you can form a general rule (which is wrong but always gives the right result) that all induction only happens through sigma bonds | |
| Nov 10, 2021 at 4:33 | comment | added | Amadeus | @Alchimista that's a very interesting point! I also thought some more about what Ron said and i no longer think it makes sense, resonance only acts in conjugated pi systems (or in presence of lone pairs or ± charges). What about induction in something like Cyclohexanone? | |
| Nov 9, 2021 at 11:43 | comment | added | Alchimista | @Amadeus that is the point I am considering. I also think that, there is no physical reason for not having inductive effect through bonds. However, if you think carefully, the Double bond is effectively a "damper", especially because one side is already electron poor and one electron reach. | |
| Nov 9, 2021 at 9:03 | comment | added | Amadeus | @Alchimista I don't think there is any reason to doubt that inductive effect would work through the sigma bond in a double bond as the physics involved is the same, so I've edited the question (and Zhu's answer also gives an example though ron has contested that, but I don't believe he disagrees either with the claim that inductive effect works through sigma bonds of double bond, just that the given example is wrong). Actually I had misinterpreted Zhu's answer earlier, now I understand that he was also only talking about inductive effect through the sigma bond in a double/multiple bond. | |
| Nov 9, 2021 at 8:54 | history | edited | Amadeus | CC BY-SA 4.0 |
edited title
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| Nov 9, 2021 at 8:24 | comment | added | Alchimista | @ron. Resonance effect delocalise electrons, inductive ones "pin" them to an atom. A double bond includes a sigma one. This last line makes the question even superfluous for a yes or no answer. It remains to see how big the effect can be, if it is worth consideration, if something useful can be concluded. And the EAS discussion seems totally different to me. It is about the prevalent effect exerted by the halogen. I will read that later. | |
| Nov 9, 2021 at 5:41 | comment | added | Amadeus | @ron oh yeah, good point. I'm most satisfied with your answer then; if you convert your comment into an answer I could accept it if you want | |
| Nov 9, 2021 at 4:25 | comment | added | ron | @Amadeus resonance can lead to partial charges on atoms. Look at the allyl carbocation for example. | |
| Nov 9, 2021 at 2:45 | comment | added | Amadeus | @ron but inductive effect is about partial charges and formation of dipoles, while resonance is supposed to be a complete dislocation? | |
| Nov 8, 2021 at 16:10 | comment | added | ron | @ Alchimista I'm not sure I buy Zhu's answer. Fluorobenzene undergoes EAS faster than chlorobenzene due to resonance effects. See this earlier answer. | |
| Nov 8, 2021 at 15:10 | comment | added | Alchimista | Sorry, I see that you were aware of the other question. If it helps, I like the answer by Zhu. | |
| Nov 8, 2021 at 14:32 | comment | added | Alchimista | @ron not really / not the point. In fact my damping example refer only to the inductive part,normally negligible. The answer is given by user Zhu in the thread I've linked just above. | |
| Nov 8, 2021 at 14:02 | comment | added | ron | It's just terminology. Electron donation or withdrawal through the sigma system is termed "inductive". Electron donation or withdrawal through the p-orbitals of a pi system is termed "resonance". | |
| Nov 8, 2021 at 13:56 | comment | added | Alchimista | Also, a couple of considerations I do: 1 statements you mentioned are about sigma and pi, not really about single & double. 2 a double bond is anyway a reservoir, it logically damps the I effect propagation through bonds. Like you need water or dump water in a tank placed between two pipe lines. | |
| Nov 8, 2021 at 13:47 | comment | added | Alchimista | The presence of double bonds implies 1)a double faced electronegativity for the C atom 2) resonance (mesomeric effect) eventually at work. This might render I effect propagating through pi bonds not so important to be a subject in introductory chapters. Look at chemistry.stackexchange.com/questions/4904/… where at least one user think as you (and me). | |
| Nov 8, 2021 at 9:17 | history | reopened |
Amadeus andselisk♦ |
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| Nov 8, 2021 at 4:08 | history | edited | Amadeus | CC BY-SA 4.0 |
added 3 characters in body
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| Nov 8, 2021 at 4:05 | review | Reopen votes | |||
| Nov 8, 2021 at 9:17 | |||||
| Nov 7, 2021 at 21:38 | history | closed |
Mithoron Mathew Mahindaratne Todd Minehardt |
Needs details or clarity | |
| Nov 7, 2021 at 17:45 | review | Close votes | |||
| Nov 7, 2021 at 21:38 | |||||
| Nov 7, 2021 at 4:31 | history | asked | Amadeus | CC BY-SA 4.0 |