NMR Question about t-butyl methyl ether

[unsung]

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Why is the peak from the t-butoxy protons upfield (= more shielded) from the peak from the methoxy protons?

Shouldn't the methoxy protons be more deshielded since they are bonded to the C that is bonded directly to the oxygen?

I know this is a simple problem but my mind's not working right now.

 

[RPedigo]

The signal at 3.2ppm is from the methyl group which is touching the oxygen (an electron withdrawing group) and therefore is deshielded. The signal at 1.2ppm is due to the tert-butyl methyl groups. These are not as deshielded because there is a carbon before those methyl groups that acts to distance the tert-butyl methyl groups from the electron withdrawing oxygen group.

 

[unsung]

The signal at 3.2ppm is from the methyl group which is touching the oxygen (an electron withdrawing group) and therefore is deshielded. The signal at 1.2ppm is due to the tert-butyl methyl groups. These are not as deshielded because there is a carbon before those methyl groups that acts to distance the tert-butyl methyl groups from the electron withdrawing oxygen group.

Wow, thanks.

 

[RPedigo]

Wow, thanks.

No problem. Hope it helped 👍

 

[HawkeyePostOp]

I want that program

 

[RPedigo]

I want that program

First image came from a program called ChemDraw, which is an awesome program.

Second image didn't come from a program at all, I pulled it from the AIST NMR database here:
http://riodb01.ibase.aist.go.jp/sdbs/cgi-bin/direct_frame_top.cgi

It has the NMR spectrum for a ridiculous amount of compounds. 👍

 

[HawkeyePostOp]

*adds to favorites*

thanks!