Why does $\ce{-NHMe}$ show -I effect. I think it should be opposite. I know that $\ce{-Me}$ groups are electron donating in nature. So the nitrogen atom will have a small $\delta^-$ charge. So then why would it still be electron withdrawing?
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1$\begingroup$ You're looking at the result and trying to use that as the starting point. The end result tells you what happened, not what is going to happen. Where did the nitrogen atom get that partial negative? By withdrawing electron density from neighboring atoms. $\endgroup$– ZheMay 29, 2020 at 13:11
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1$\begingroup$ @Zhe ok I think I got it. The nitrogen atom is electronegative, that is why it is withdrawing electrons from all three bonds. My reasoning was like saying that we have a sink hole, and since water is pouring in from the left, water can't pour in from the right. Thanks $\endgroup$– gauri agrawalMay 29, 2020 at 13:35
1 Answer
The inductive effect is reflective of the comparison of electronegativity between an -R group and carbon. There is an -I effect because the nitrogen is more electronegative than carbon, so it will inductively withdraw electrons. I will also note that the inductive effect is measured relative to the -R group being hydrogen.