Match each of the 1 H NMR spectra with one of the following compounds: b. <IMAGE>

Hello everyone. Let's do this problem together. It says true or false. The proton N M R spectrum below corresponds to the given compound. And the compound we are given is the structure of two methyl, three hexen. All right. So how can we determine if the structure is represented by the correct proton N M R spectrum? We can look at a few different characteristics of our spectrum and see if they match what would be produced by looking at the structure. So first, we can look at how many signals would be produced by our structure. Then we can look at the integration of those signals. So how many protons are represented by each signal? Then we can look at the multiplicity which tells us the number of neighboring protons, right based on whether the signal is a singlet doublet triplet. And that is determined by the expression N plus one where N is the number of neighboring protons. And lastly, we can look at the chemical shift. So if a proton is close to an electron dense group, then it will be more d shielded, right? Because that electron dense group will draw in the electron density leaving those protons more naked or de shielded, resulting in a higher chemical shift. So let's look at these characteristics for our structure and see if they match our spectrum. So first question, how many signals will this structure produce? Well, we'll produce one for both of these methyl groups, right? They are equivalent, they are coming off of the same carbon. Then we'll have a second one for this methane protein proton, not protein. Then we have two hydrogens methylene group there next to the carbonyl group, another methylene group. So that is four signals and another methyl group. So that is five signals. OK. Does our proton N M R spectrum have five signals? Yes, 12345. So we are, we are potentially in the true answer, right? That this could be a match. Let's look at the integration of these signals. So signal A has six hydrogens signal B represents one hydrogen signal. C represents two hydrogens signal, D represents two hydrogens and signal E represents three hydrogens. So let's just look and see if these integration values match the ones that we see on our spectrum, not even considering the order or anything. So we have 6122361223. OK. So that is potentially a match moving on to the multiplicity of these signals. So neighboring protons to signal A, we have one neighboring proton. So that six H signal will be a double it. And that matches structure B or sorry, signal B has six neighboring protons. So that will be a septet. Do we have a one H septet? Yes, we do downfield. Then we have signal C has two neighboring protons. So that will be a triplet, a two inch triplet. Yep, I see that in our spectrum signal D has neighboring proton. So that will be a six tet. And I see that at around 1.7 P pm and lastly signal E we have two neighboring protons. So that will be a triplet with integration three H and I see that right below one P PM. So this all so far is telling us that this spectrum does in fact match our structure. Let's check the chemical shift. So based on the multiplicity, we said from left to right, we would have one H subset that would be signal B two H triplet, that would be single C two H sextet, that would be signal D six H double it, that would be signal A and three H triplet that would be signal E. So let's see the position of these hydrogens on the structure. And see if there are any electron dense groups, we do have a ketone group, right, a carbon group. So I noticed that signal B that single proton is right next to the carbon group, right? Well, so is signal C but carbon B only has one proton. So having shared, having to not share that carbon with other protons is going to make it more d shielded. So that makes sense why proton B is the most down field protons C are also right next to that car Carboni group as we mentioned. So that makes sense why those are the next most downfield, then we have protons in signal D. Those are the next closest to the Carboni group besides those six methyl protons. But remember what I just said about the number of protons, right? These are only two protons on carbon D. So those will be the more D shielded protons, then protons A and the three methyl protons for signal E are the furthest away from that Carboni group. So those will be the most up field. So we checked everything and all of those characteristics tell us that the answer for this problem is true. This structure of compound two methyl, three hexen is represented by this proton N M R spectrum. That's it for this one. I hope this video is helpful and thanks for watching.

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1. A Review of General Chemistry5h 5m
2. Molecular Representations1h 14m
3. Acids and Bases2h 46m
4. Alkanes and Cycloalkanes4h 17m
5. Chirality3h 39m
6. Thermodynamics and Kinetics1h 22m
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12. Alcohols, Ethers, Epoxides and Thiols2h 42m
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14. Synthetic Techniques1h 26m
15. Analytical Techniques:IR, NMR, Mass Spect7h 3m
16. Conjugated Systems6h 13m
17. Ultraviolet Spectroscopy51m
18. Aromaticity2h 34m
19. Reactions of Aromatics: EAS and Beyond5h 1m
20. Phenols55m
21. Aldehydes and Ketones: Nucleophilic Addition4h 56m
22. Carboxylic Acid Derivatives: NAS2h 51m
23. The Chemistry of Thioesters, Phophate Ester and Phosphate Anhydrides1h 10m
24. Enolate Chemistry: Reactions at the Alpha-Carbon1h 53m
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33. The Organic Chemistry of Metabolic Pathways2h 52m
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35. Transition Metals6h 14m
36. Synthetic Polymers1h 49m

15. Analytical Techniques:IR, NMR, Mass Spect

NMR Practice

Organic Chemistry

15. Analytical Techniques:IR, NMR, Mass Spect

NMR Practice

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7:11 minutes

Problem 53b

Textbook Question

Match each of the ¹H NMR spectra with one of the following compounds:

b. <IMAGE>

Verified step by step guidance

Step 1: Analyze the chemical shift values (in ppm) on the x-axis of the 1H NMR spectrum. The spectrum ranges from approximately 0 to 3 ppm, which suggests the presence of protons in an aliphatic environment (no aromatic or highly deshielded protons).

Step 2: Examine the integration values provided above each peak. The integration values indicate the relative number of protons contributing to each signal: 1H, 2H, 2H, 6H, and 3H. These values correspond to the number of hydrogens in different chemical environments.

Step 3: Consider the splitting patterns of the peaks. The splitting patterns (multiplets) are caused by spin-spin coupling with neighboring protons. For example, the 1H peak appears as a multiplet, suggesting it is coupled to adjacent protons. Similarly, the 2H peaks are also multiplets, indicating coupling with nearby protons.

Step 4: Match the chemical shift values and integration data to possible functional groups. For instance, the peak at approximately 1 ppm with an integration of 6H likely corresponds to two equivalent methyl groups (-CH3) in a symmetrical environment. The peak at approximately 3 ppm with an integration of 1H may correspond to a proton near an electronegative atom or functional group.

Step 5: Use the integration, chemical shift, and splitting data to deduce the structure of the compound. Compare the spectrum to the provided list of compounds and identify the one whose structure matches the observed NMR data. Ensure that the number of protons and their environments align with the spectrum.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

1H NMR Spectroscopy

Proton Nuclear Magnetic Resonance (1H NMR) spectroscopy is a powerful analytical technique used to determine the structure of organic compounds. It provides information about the number of hydrogen atoms in different environments within a molecule, indicated by peaks in the spectrum. The position of these peaks, measured in parts per million (PPM), reflects the electronic environment surrounding the hydrogen atoms.

Chemical Shift

Chemical shift refers to the position of a peak in an NMR spectrum, which indicates the electronic environment of the hydrogen atoms. Different functional groups and molecular structures influence the chemical shift, causing protons in different environments to resonate at different frequencies. Understanding chemical shifts is crucial for interpreting the spectrum and identifying the types of hydrogen present in a compound.

Integration and Multiplicity

Integration in 1H NMR refers to the area under each peak, which correlates to the number of hydrogen atoms contributing to that signal. Multiplicity describes the splitting pattern of the peaks, which arises from neighboring hydrogen atoms (n+1 rule). Analyzing both integration and multiplicity helps in deducing the number of hydrogen atoms and their connectivity in the molecular structure.

Match each of the 1H NMR spectra with one of the following compounds: b. <IMAGE>

Key Concepts

1H NMR Spectroscopy

Chemical Shift

Integration and Multiplicity

Match each of the ¹H NMR spectra with one of the following compounds:

b. <IMAGE>