The Study Cycle – It Works ! P preview, preread – look at figures, bold A attend and ask R review soon S study serially – repetition is the key P problems, problems, problems & pencils A focus on approach needed in problem R reflect, assess, self test
Chemistry 250-02 Organic Chemistry I Fall, 2014 Day 25 11/3/14 Organic Chemistry I Fall, 2014 Day 25 11/3/14 Structure Determination and Spectroscopy Chapter 13 (NMR) & ChemAct L-03,L-04
NMR
Reaction Types
Substitution vs. Elimination How can we identify and distinguish between these two compounds?
Nuclear Magnetic Resonance odd atomic number (# p) or odd atomic mass (# p + # n)
The NMR Spectrometer
The Drew NMR Spectrometer !
NMR Active Nuclei
1H TMS TT 13C TMS
13C NMR and 1H NMR 1H 13C
13C NMR and 1H NMR 13C 1H
13C NMR
13C NMR 3 1 4 2
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Chem Act L-03 13C NMR Models 1 - 2
Chem Act L-03 QCT 11
The painkiller Demerol has the structure shown below The painkiller Demerol has the structure shown below. How many peaks would you expect to see in the 13C NMR spectrum of this substance? 10 11 12 14 15
Which of the following molecules best fits the following 13C NMR data Which of the following molecules best fits the following 13C NMR data? 13C NMR data: 20, 22, 32, 44, 67 ppm 1. 2. 4. 3.
Chem Act L-03 Models 3 - 6
13C NMR 1H undecoupled = coupled or 1H decoupled coupled decoupled
13C NMR 2-bromobutane decoupled undecoupled
Chem Act L-03 Exercise 3 page 293
13C NMR How many different carbons ?
How many signals will appear in the decoupled 13C NMR spectrum of the following molecule? 2 3 4 5
Problem 13.51 Assign the Peaks
Problem 13.51 Assign the Peaks meta ortho CH2 CH3 para C=O ipso
13C NMR Are the peak heights (areas) identical ?
What is the pattern of signals in the undecoupled 13C NMR spectrum of the following molecule? s s d t q s d d t q d d s d q s s s t q d d d d q
How many signals will appear in the 13C NMR spectrum of the following molecule? 4 5 6 7
Advanced 13C NMR DEPT 90 for CH only CH3 positive DEPT 135 DEPT 90 for CH only CH3 positive DEPT 135 CH2 negative
Uses of 13C NMR E2 How many different carbons ?
Problem 13.59
Sponsor: Tri-Beta Co-sponsors: DUBS, DUCS, GSE, MIND, DHO Science Internship Panel Are you looking for an internship but don’t know where to get started? Come hear about internships completed by your peers! Speakers covering topics in: biology, neuroscience, chemistry, physics, ESS, medicine and veterinary Sponsor: Tri-Beta Co-sponsors: DUBS, DUCS, GSE, MIND, DHO Time: 5:30 pm Date: November 6th Location: Crawford Hall
Spectroscopy Problems http://sdbs.db.aist.go.jp/sdbs/cgi-bin/direct_frame_top.cgi
13C NMR Problems – C5H11Cl
1H NMR Chem Act L4
The Chemical Shift
1H NMR Look Complicated – Why ? 1H 13C undecoupled 13C decoupled
Spin-Spin Coupling (JHz)
# Peaks = N + 1
ChemAct 1S-6
Spin-Spin Splitting (Multiplicity)
Homotopic, Enantiotopic, Diastereotopic
What Kinds of H’s Are These ? Problems 13.13, 13.40, 13.40
Problem 13.53 C3H6Br2
Problem 13.54 C4H7O2Cl IR 1740 cm-1
Problem 13.45a C4H9Br
Problem 13.45b C4H8Cl2
Problem 13.57 C8H9Br
Problem 13.58a C5H10O
Problem 13.58b C7H7Br
Problem 13.58c C8H9Br
Uses of NMR
How Can You Distinguish?
Problems 13.43 and 13.49 How Can You Distinguish by NMR ?
Problem 13.50 How Can You Distinguish by IR, NMR and UV ?
C60