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How can you determine the ratio of cis and trans from H NMR spectrum?
How can you determine the ratio of cis and trans from H NMR spectrum? Specifically for cis- and trans- 2-methylcycohexanol. What would would the ratio be? I know it has something to do with the coupling, but I have no idea how to go about it.
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.
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November 11th, 2009
Posted by admin in trans |
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.
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