a. The first peak at 6.92 corresponds to the two hydrogen atoms on the benzene ring closest to the ester group on the edge of the molecule. These two hydrogen atoms are couples with each other because of symmetry. They are also very desheilded because they are part of an aromatic ring.
b. The second peak at 6.99 is analogous of that to the peaks at 6.92. Both of these groups have a doublet splitting pattern because they only couple with one another.
c. The peak at 5.97 refers to one of the hydrogen atoms on the trans double carbon to carbon double bond. The J value of this is the same as the J value for d because they are coupling with one another.
d. The peak at 5.69 is analogous to that of the peak at 5.67. The difference is that this atom branches out further from the molecule. As stated before these two have the same J-values.
e. The peak at 5.55 corresponds to the hydrogen atom on the upper carbon to carbon double bond. This hydrogen atom only couples as a singlet because it does not have any neighbors, but it is still deshilded because it is attached to the double bond.
f. This peak signifies the two hydrogen atoms between the ester and the benzene ring. Normally the ppm value is near 3.8 when hydrogen atoms are near esters, but in this case it is higher because a benzene ring is present.
g. There are 4 groups that are all very similar and they couples in the same region as singles. All of these signals represent methyl groups that are leading off of the molecule by an ester group. The ester group causes the hydrogen atoms to become more deshilded.
h. The groupings present in this group are very similar to the previous. The difference is that these are smaller groups of hydrogen atoms that don't lead off of the molecule and instead are part of rings or chains with adjacent esters.
i. This coupling represents a single hydrogen atom that has been placed next to an ester group that results in deshilding. This hydrogen atom, however, yields a multiplet because there are 5 hydrogen neighbors.
j. These two peaks are analogous to that of the previous hydrogen atom accept that they are placed within a ring that prevents them from becoming as deshilded.
k. This peak is a large singlet that6 signifies a single hydrogen atom. This hydrogen atom is connected to the carbon to carbon triple bond on the edge of the molecule. This configuration leaves the lone hydrogen atom slightly deshilded.
l. The two peaks labeled for l are coupled together because they have symmetry. They are also diastereotopic with the closest hydrogen atoms which results in a coupling constant. As a result they form multiplets.
m. These two hydrogen atoms are exactly the same as the previous grouping except that they are on the other face of the molecule.
n. The three ppms identified signify groupings of 2 hydrogen atoms connected to a tetrahedral carbon that is only attached to other carbons. As a result it has a very low ppm.
o. The groupings for o and p signify groupings of 2 methyl groups that are attached to a tetrahedral carbon. As a result they have no neighbors and extremely low coupling constants. These groups do not split and show up as singlets.
_
Product
_
a. The first peak at 6.92 corresponds to the two hydrogen atoms on the benzene ring closest to the ester group on the edge of the molecule. These two hydrogen atoms are couples with each other because of symmetry. They are also very desheilded because they are part of an aromatic ring.
b. The second peak at 6.99 is analogous of that to the peaks at 6.92. Both of these groups have a doublet splitting pattern because they only couple with one another.
c. The peak at 5.97 refers to one of the hydrogen atoms on the trans double carbon to carbon double bond. The J value of this is the same as the J value for d because they are coupling with one another.
d. The peak at 5.69 is analogous to that of the peak at 5.67. The difference is that this atom branches out further from the molecule. As stated before these two have the same J-values.
e. The peak at 5.55 corresponds to the hydrogen atom on the upper carbon to carbon double bond. This hydrogen atom only couples as a singlet because it does not have any neighbors, but it is still deshilded because it is attached to the double bond.
f. This peak signifies the two hydrogen atoms between the ester and the benzene ring. Normally the ppm value is near 3.8 when hydrogen atoms are near esters, but in this case it is higher because a benzene ring is present.
g. There are 4 groups that are all very similar and they couples in the same region as singles. All of these signals represent methyl groups that are leading off of the molecule by an ester group. The ester group causes the hydrogen atoms to become more deshilded.
h. The groupings present in this group are very similar to the previous. The difference is that these are smaller groups of hydrogen atoms that don't lead off of the molecule and instead are part of rings or chains with adjacent esters.
i. This coupling represents a single hydrogen atom that has been placed next to an ester group that results in deshilding. This hydrogen atom, however, yields a multiplet because there are 5 hydrogen neighbors.
j. These two peaks are analogous to that of the previous hydrogen atom accept that they are placed within a ring that prevents them from becoming as deshilded.
k. This peak is a large singlet that6 signifies a single hydrogen atom. This hydrogen atom is connected to the carbon to carbon triple bond on the edge of the molecule. This configuration leaves the lone hydrogen atom slightly deshilded.
l. The two peaks labeled for l are coupled together because they have symmetry. They are also diastereotopic with the closest hydrogen atoms which results in a coupling constant. As a result they form multiplets.
m. These two hydrogen atoms are exactly the same as the previous grouping except that they are on the other face of the molecule.
n. The three ppms identified signify groupings of 2 hydrogen atoms connected to a tetrahedral carbon that is only attached to other carbons. As a result it has a very low ppm.
o. The groupings for o and p signify groupings of 2 methyl groups that are attached to a tetrahedral carbon. As a result they have no neighbors and extremely low coupling constants. These groups do not split and show up as singlets.
p. Stated in the previous point.
q. The quartet that appears at 1.4 ppm has an integral value of 6. This represents the three groupings of 2 hydrogen atoms each. Each of these groups of hydrogen atoms are coupling with the methyl groups at the end of the molecule. The reason why there is a not separate coupling constant is because there is symmetry within the molecule at this point.
r. The triplet that appears here is every similar to the previous coupling. The integral value of 9 signifies 3 different methyl groups that are all coupling with the previous 6 hydrogen atoms. Because of symmetry, a triplet appears.
s. The last signal is actually very weak but it is broad at around 2 ppm because it is a hydrogen atom attached to an oxygen atom. As a result it is deshilded.