# Spectroscopy Instruction Guide## Instructions for Completing Spectroscopy Problems:1. **READ THE DIRECTIONS TO EACH QUESTION CAREFULLY** - Not following the directions means you get the question wrong!2. **FORMAT YOUR ANSWERS AS DIRECTED** - Formatting your answers incorrectly means you get the question wrong!## Reference Tables for IR Regions and NMR Chemical Shifts:The following information provides details on IR regions and NMR chemical shifts to aid in solving spectroscopy problems.### $ ^1H $ NMR Chemical Shifts (ppm)- **12 - 10 ppm**: Carboxylic acids (RCOOH)- **10 - 9 ppm**: Aldehydes (RCHO)- **9 - 6.5 ppm**: Aromatic protons (Ar-H)- **6.5 - 4.5 ppm**: Olebinic protons (alkenes) (C=CH)- **4.5 - 2.5 ppm**: Protons attached to electronegative atoms (e.g., halogens, oxygen, nitrogen) (H-C-X)- **2.5 - 2 ppm**: Allylic protons (C=C–C-H)- **2 - 1 ppm**: Alkyl groups attached to electronegative atoms (H-C-C)- **1 - 0 ppm**: Methyl groups (CH3)### IR Spectroscopy (cm$^{-1}$)- **4000 - 3000 cm$^{-1}$**: - **Broad peak ~ 3400 cm$^{-1}$**: Alcohols and phenols (O-H) - **~ 3300 cm$^{-1}$**: N-H stretch (amines, amides) - **3250 - 3300 cm$^{-1}$**: Alkynes (≡C-H) - **3000 - 2850 cm$^{-1}$**: Alkane C-H stretch - **3100 - 3000 cm$^{-1}$**: Alkene (C=CH) - **2730 - 2820 cm$^{-1}$**: Aldehydes (2 peaks) - **2200 cm$^{-1}$**: Nitriles (C≡N), Alkynes (C≡C) - **2000 - 1700 cm ---### Identifying the Correct Product Using ^1H-NMR SpectrumIn this section, we’ll explore a reaction scheme and use a ^1H-NMR (proton nuclear magnetic resonance) spectrum to identify the final product. Proper interpretation of the spectrum will allow us to determine which product is formed.#### Reaction Scheme and ProductsBelow is the reaction scheme and the possible products resulting from the reaction.![reaction scheme and products]The given products are:1. Product 12. Product 23. Product 34. Product 45. Product 5#### ^1H-NMR Spectrum AnalysisTo make sense of the NMR spectrum and accurately identify the product, we need to analyze the chemical shifts and splitting pattern of the protons:![NMR Spectrum]- **Chemical Shifts**: - Peaks at approximately 1.2-1.3 ppm corresponding to 6H (likely two equivalent methyl groups) - Peak at approximately 2.8 ppm corresponding to 1H (likely associated with a proton adjacent to a bromine or similar group) - A peak at 1.6 ppm corresponding to 3H (likely associated with a methyl group adjacent to a deshielding environment)---#### Follow-up Questions for Analysis1. **What functional group is indicated by the 2H at 5.7 ppm?** _Answer here:_2. **Identify the splitting pattern of the 3H at 1.6 ppm. What is this pattern called?** _Answer here:_3. **Determine which product matches the ^1H-NMR spectrum below.** Given Splitting Patterns: ``` Peaks: (s = singlet, d = doublet, t = triplet, m = multiplet) ``` - **Spectrum Image:** ![spectrum] Using the information above, identify the product number (1, 2, 3, etc.). _Answer here:_---

Answered: Image /qna-images/answer/e7ceba32-cbfd-4c28-92d4-83e34978a600.jpg

Let's take another approach to that last reaction from the previous problem... Below is a similar reaction scheme, but this time, you are given the ¹H-NMR spectrum of the final product. If you interpret the spectrum correctly, then you should be able to identify the correct product from list below (enter your answer in the space provided only use the product number for your answer: 1, 2, 3, etc.). Then, answer any follow-up questions a. 6 2H 6 Br Product 1 t 5 5 Br Br Luxe Product 4 Product 2 4 S Product 3 3 PPM NBS light i. The 2 hydrogens (2H) at 5.7 ppm chemical shift represent those attached to what functional group? PPM 6H m 2 ii. The 3 hydrogens (3H) at 1.6 ppm chemical shift are split. What do we call this splitting pattern? iii. Which one of the products above matches the ¹H-NMR below (note: integration is not provide on purpose but you are given the splitting patterns) (Simply answer by entering the correct product number: 1, 2, 3, etc.)? 2 3H S Br Product 5 1 1 t 0 0

Let's take another approach to that last reaction from the previous problem... Below is a similar reaction scheme, but this time, you are given the ¹H-NMR spectrum of the final product. If you interpret the spectrum correctly, then you should be able to identify the correct product from list below (enter your answer in the space provided only use the product number for your answer: 1, 2, 3, etc.). Then, answer any follow-up questions a. 6 2H 6 Br Product 1 t 5 5 Br Br Luxe Product 4 Product 2 4 S Product 3 3 PPM NBS light i. The 2 hydrogens (2H) at 5.7 ppm chemical shift represent those attached to what functional group? PPM 6H m 2 ii. The 3 hydrogens (3H) at 1.6 ppm chemical shift are split. What do we call this splitting pattern? iii. Which one of the products above matches the ¹H-NMR below (note: integration is not provide on purpose but you are given the splitting patterns) (Simply answer by entering the correct product number: 1, 2, 3, etc.)? 2 3H S Br Product 5 1 1 t 0 0

Organic Chemistry: A Guided Inquiry

2nd Edition

ISBN:9780618974122

Author:Andrei Straumanis

Publisher:Andrei Straumanis

ChapterL1: Infrared Spectroscopy

Section: Chapter Questions

Problem 16CTQ

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answer EACH PART very clearly please dont make it confusing, this is chem 2600, physical chemistry course!!!! please draw it seperately clearly!! fast answer .
8. In real life, NMR samples often contain impurities, so extra signals will appear on your spectrum that are not related to your product. The document "Common NMR impurities" lists some common impurities and their NMR data. Here are some instructions for reading this document: o Use Table 1 on page 2 of the document, focusing on the column for CDCI3. (This is the NMR solvent we are using.) o The impurities are listed in the first column. o The "mut" column tells you the multiplicities those signals should have. • s = singlet, d = doublet, t = triplet, q = quartet, etc. o The numbers in the table are the chemical shifts that certain impurities appear at. o For example, if diethyl ether is present in your sample, you should see two signals: a triplet at 1.21 ppm and a quartet at 3.48 ppm.
Once again, the question is included in the problem. I want to compare it to my answer!
ucumberlands.blackboard.com Remaining Time: 38 minutes, 35 seconds. Question Completion Status: AMoving to another question will save this response. Question 10 Which of the indicated hydrogen atoms would have the greatest chemical shift (farthest downfield) in the proton NMR spectrum? Br Br Cl Cl b. а. с. Cl Br cl Н Н d. е. C D A Moving to another question will save this response. MacBook Air II F8 F10 F9 F7 O00 F4 F6 F5 F3 F2 & $ # 0 8 7 6 4 OOC
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