Comments on: How can you determine the ratio of cis and trans from H NMR spectrum? http://cutframetv.com/trans/how-can-you-determine-the-ratio-of-cis-and-trans-from-h-nmr-spectrum Mon, 21 May 2012 14:36:41 +0000 http://wordpress.org/?v=2.7 hourly 1 By: lightgreen http://cutframetv.com/trans/how-can-you-determine-the-ratio-of-cis-and-trans-from-h-nmr-spectrum/comment-page-1#comment-10177 lightgreen Wed, 11 Nov 2009 17:02:59 +0000 http://cutframetv.com/trans/how-can-you-determine-the-ratio-of-cis-and-trans-from-h-nmr-spectrum#comment-10177 i think the ratio of cis and trans-2-methylcyclohexanol can be determined by the signal intensity of chemical shift of hydrogen atom on methyl group and/or carbon #2. hydroxyl group is an electron-withdrawing group. As a result, the hydrogen atoms near hydroxyl group will be deshielding. however sheilding constant (sigma) has a strong relationship with distance. hydrogen atoms on methyl group of trans-2-methylcyclohexanol have longer distance than cis one, and the signal of hydrogen atoms on methyl group will shift to downfield.<br><b>References : </b><br> i think the ratio of cis and trans-2-methylcyclohexanol can be determined by the signal intensity of chemical shift of hydrogen atom on methyl group and/or carbon #2.

hydroxyl group is an electron-withdrawing group. As a result, the hydrogen atoms near hydroxyl group will be deshielding.
however sheilding constant (sigma) has a strong relationship with distance.

hydrogen atoms on methyl group of trans-2-methylcyclohexanol have longer distance than cis one, and the signal of hydrogen atoms on methyl group will shift to downfield.
References :

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