UNIVERSITY OF VICTORIA FINAL EXAMINATION - DECEMBER …web.uvic.ca/~chem213/Che213Final12VersB-corr.pdf · chem 213 final examination 2012 version b page 1 of 21 university of victoria

Chem 213 Final Examination 2012 Version B Page 1 of 21

UNIVERSITY OF VICTORIA

FINAL EXAMINATION - DECEMBER 2012

CHEMISTRY 213 PRACTICAL SPECTROSCOPY

TIME: 3 HOURS

INSTRUCTOR: Dr. Dave BERG

IN THIS EXAM THERE SHOULD BE 21 IVORY EXAM PAGES

+ SEPARATE WHITE SIGNATURE SHEET

YOU ALSO SHOULD HAVE

A GREEN COMPUTER SHEET

AN IVORY ANSWER SHEET PACK (2 sheets, 4 sides)

A PINK DATA SHEET PACK (4 sheets, 8 sides)

Report to the invigilator if any of these are missing now

QUESTIONS 2-47 [1.5 pts each = 69 pts]: use the green computer sheets and a pencil.

QUESTIONS A-H [81 pts total]: answer these on the ivory sheets provided.

Total marks = 150; Total minutes = 180

Make sure you code your name (last name, space, first name) AND registration number V0-

0123456 (code ONLY the last 7 digits) on BOTH the green computer sheet AND the ivory

answer sheet – do this NOW and sign the blue sheet.

Place your student ID at the top right corner of the table.

Non-programmable electronic calculators are permitted.

NOTES: a) answers may be used more than once for the numbered questions b) some questions may require data supplied on the pink data sheets!

***** THIS IS EXAM VERSION B ***** CODE B FOR QUESTION 1 ON THE SCANTRON SHEET NOW!


Using the choices (in Hz): (a) 4 x 1013 (b) 5 x 109 (c) 4 x 1010 (d) 6 x 1014 (e) 4 x 108 (f) 1 x 1014 (g) 6 x 1012 (h) 1 x 1015 (i) 5 x 1015 (j) 3 x 1018

2. Which frequency would be closest to a typical C-O stretch in the IR spectrum? 3. Which frequency has an energy equivalent to 240 kJ mol-1?

Consider the molecule formamide HC(=O)NH2 (at right) and use the following frequencies (cm-1) to answer questions 4-8:

(a) 810 (b) 1630 (c) 1660 (d) 1690 (e) 2410 (f) 2490 (g) 2750 (h) 3310 (i) 3350 (j) 5000

4. Which best corresponds to the C-H stretch? 5. Which best corresponds to the asymmetric N-H stretch? 6. Which best corresponds to the symmetrical N-D stretch if formamide is dissolved in

D2O? 7. Which best corresponds to the CO stretch? 8. Which best corresponds to the second overtone of the CO stretch? Using the following choices:

(a) 16 (b) 15 (c) 14 (d) 13 (e) 12 (f) 11 (g) 10 (h) 9 (i) 8 (j) 7 9. How many possible vibrations are expected for formamide? Using the following choices: (a) P (b) R (c) PR (d) PQ (e) RQ

(f) none (g) PQRS (h) PQR (i) Q only 10. Assuming you can see the rotational fine structure of formamide, what branches

would you expect to see for the N-H stretch?

Using the following choices: (a) 8 (b) 7 (c) 6 (d) 5 (e) 4 (f) 3 (g) 2 (h) 1 (i) 0 11. How many bending vibrations of planar BF2Cl are IR inactive?


Consider the trigonal planar molecule HB(PF2)2 (at right) in answering the following questions. The B-H bond is NOT acidic and does not exchange with D2O. 13. If the 11B resonance frequency is 200 MHz, what will the 19F resonance frequency be

on the same instrument? (a) 600 (b) 556 (c) 250 (d) 244 (e) 164

(f) 160 (g) 100 (h) 72 (i) 67 (j) 40 14. How many lines total will be observed in the 1H NMR at room temperature

assuming all lines are resolved, all B is 11B and free rotation around the B-P bond is rapid?

(a) 108 (b) 60 (c) 30 (d) 27 (e) 15 (f) 12 (g) 5 (h) 4 (i) 3 (j) 1 15. How many lines total will be observed in the 11B (non-decoupled) NMR at room

temperature assuming all lines are resolved and rotation around the B-P bond is rapid?

(a) 120 (b) 108 (c) 54 (d) 30 (e) 18 (f) 15 (g) 6 (h) 5 (i) 3 (j) 2 16. Assuming that rotation about the B-P bond becomes very slow at low temperature

and the planar structure drawn above is locked in place, what will the spin system become under these conditions (assume 100% 11B)?

(a) ABC2D4 (b) ABCC’D2D2’ (c) ABM2X4 (d) AFM2X4 (e) AFMM’X4 (f) AFM2X2X2’ (g) AFMM’RR’YY’ (h) AFM2R2Y2 (i) AFMM’R2Y2 (j) AFMNR2Y2

H

BP P

F

FF

F11

12. If a C-F stretch has a fundamental frequency of 1050 cm-1, what is the zero point energy for this vibration in kJ mol-1? (a) 12.6 (b) 126 (c) 63 (d) 6.3 (e) 25.2 (f) 252 (g) 1.26 (h) 0.63 (i) 0.126 (j) 0.252


For the molecule cis-Pt(Cl)(F)(PCl3)2 (at right) Using the following answers: (a) 1:1:1:1:2:2:2:2:1:1:1:1 (b) 1:2:1:4:8:4:1:2:1 (c) 1:1:1:1:4:4:4:4:1:1:1:1 (d) 1:2:1:2:4:2:1:2:1 (e) 1:1:2:2:1:1 (f) 1:2:1:1:2:1 (g) 1:3:3:1 (h) 1:2:2:1 17. What is the relative intensity pattern of the lines observed in the

19F (non-decoupled) NMR?

18. What is the relative intensity pattern of the lines observed in the 195Pt{1H} NMR assuming that 1JPt-F > 1JPt-P?

The nerve agent Sarin, shown at right, contains a chiral phosphorus. Assume 4JHF and 4JHP are observable (about 4-5 Hz) but 4JHH =0 Hz. 19. What is appearance of the proton-coupled 19F NMR spectrum? (a) s (b) d (c) t (d) dd (e) dt (f) td (g) ddd (h) dqd (i) dtd (j) d of pentet 20. How many lines are MOST likely for the O-CH resonance in the 1H NMR? (a) 64 (b) 32 (c) 28 (d) 16 (e) 14 (f) 8 (g) 7 (h) 4 (i) 2 (j) 1 21. How many chemically inequivalent methyl resonances are there in this molecule? (a) 3 (b) 2 (c) 1 22. Under what conditions is the O-CH proton exchangeable? (a) never (b) always (c) at high temperature (d) at low temperature

Pt

F PCl3

Cl PCl3


2,4-D (at right) is a major component in the defoliant Agent Orange. Using the following choices: (a) 172.5 (b) 158.4 (c) 141.8 (d) 140.3 (e) 132.4 (f) 128.5 (g) 116.7 (h) 112.6 (i) 110.1 (j) 198.6 23. What is the most likely chemical shift for C1? 24. What is the most likely chemical shift for C8? Using the following choices: (a) 6.69 (b) 6.80 (c) 6.93 (d) 7.15 (e) 2.35 (f) 3.40 (g) 4.25 (h) 5.25 (i) 7.45 (j) 7.77 25. What is the most likely chemical shift for the H on C7? 26. What is the most likely chemical shift for the H on C6? Using the following choices: (a) A2X (b) AA’X (c) ABX (d) AMX (e) ABC (f) A3 (g) A2B 27. What is the spin system designation for the aromatic protons of 2,4-D at 90 MHz if

the chemical shift for the H on C3 is 7.19 ppm and the H on C5 is 7.10 ppm? 28. What is the spin system designation for the aromatic protons of 2,4-D at 500 MHz if

the chemical shift for the H on C3 is 7.19 ppm and the H on C5 is 7.10 ppm? 29. In the long range HMQC (10 Hz), C1 would show a correlation to protons on which

numbered carbon(s)? (a) 5, 6 (b) 5, 7 (c) 6, 7 (d) 3, 5, 7 (e) 3, 6, 7 (f) 6 (g) 7 (h) 3, 5 (i) 3, 6 (j) 3, 7


30. What is the appearance of the 13C{1H} NMR spectrum of deuterated dichloromethane, CD2Cl2?

(a) no signal (b) singlet (c) doublet (d) 1:1:1 triplet (e) 1:3:3:1 quartet (f) 1:2:3:2:1 pentet (g) 1:4:6:4:1 pentet (h) 1:2:1 triplet (i) 1:5:10:10:5:1 sextet (j) 1:3:6:7:6:3:1 septet

Answer Questions 31-35 using the molecules below (some may be used more than once)

A B C D

E F G

H I J

I

CH3

H3CS SCH3

SCH3

OClCl

FBr

HN

Br

Br

P

O

CH3

CH3H3CS

HSi

OCH3

OCH3

OCH3

OH

Cl

O

H3C CH3

CH2CH3

CH2CH3

N

CH3

Si(CH3)3H3C

OH

31. Which molecule is likely to show a strong fragment ion at m/e = 91? 32. Which molecule will show an M+2 peak that is about 13% the size of M+? 33. Which molecule will show a base peak at 127 less than the parent ion peak? 34. Which molecule will show an M+1 peak that is 13% of the M+ peak? 35. Which molecule will show an M+2 peak that is 33% the size of the M+ peak?


The conjugated aldehyde retinal, also known as Vitamin A aldehyde, is shown on the right. 39. How does the UV-vis spectrum of retinal compare with that of acetaldehyde (CH3CHO)? (a) hyperchromic and hypsochromic shifts occur (b) hyperchromic and hypochromic shifts occur (c) hyperchromic and bathochromic shifts occur (d) hypochromic and bathochromic shifts occur (e) hypochromic and hypsochromic shifts occur (f) bathochromic and hypsochromic shifts occur 40. Which wavelength (in nm) is the best estimate of the lowest energy π→π* absorption

for retinal? (a) 750 (b) 680 (c) 610 (d) 540 (e) 470 (f) 365 (g) 254 (h) 225 (i) 190 (j) 175

Using the following choices:

(a) → * (b) charge transfer (c) n → σ* (d) σ → * (e) d → d

(f) n → π* (g) →d (h) σ → σ*

36. Which corresponds to the shortest wavelength absorption of ethene, H2C=CH2, in the

vacuum ultraviolet? 37. Which transition is responsible for the intense orange colour of dichromate, Cr2O7

2- ? 38. Which transition occurs at longest wavelength for benzophenone, (C6H5)2C=O?

H

O


The objective in the following questions is to determine the molecular formula, solve the structure and/or identify the correct isomer, depending on the question. Your FINAL answers must be written on the ivory sheets in the appropriate place; giving more than one answer will result in penalties! There are some questions to answer on the green scantron form as well.

Compound A shows an M+ at m/e 176 and also peaks at 177, 178 and 179 in 100:4:98:4 ratio. A strong fragment peak was seen at m/e 97 along with a related isotopic peak at 98 in 100:4 ratio. This fragment contains only C, H and O. The infrared spectrum of A is shown below.

Determine the molecular formula of compound A and write it in the space provided on the ivory answer sheet. [3 marks] 41. How many double bond equivalents are there in COMPOUND A? (a) 0 (b) 1 (c) 2 (d) 3 (e) 4 (f) 5 (g) 6 (h) 7 (i) 8 (j) 9 Determine the molecular structure of compound A and write it in the space provided on the ivory answer sheet. [5 marks]

Workspace:


Compound B has the formula C8H6Cl2O2 and shows the following IR:

The compound shows only three 1H NMR resonances at δ 7.24 (d, J = 8 Hz), 6.82 (d, J = 8 Hz), 4.89 (s) that integrate to 2H each. Determine the structure of B and draw it on the ivory answer sheet. [8 marks]

Workspace:


The NOESY AND COSY spectrum of compound C are shown on the next two pages. Make use of NOESY or COSY spectrum and chemical shift values to decide which isomer of C is the correct one. Enter the number of the structure you have chosen on the ivory answer sheet. [8 marks] Answer choices:

1 2 3 4 5

6 7 8 9 10

11 12 13 14

NH2 NH2 NH2 NH2 NH2

NH2 NH2

NH2 NH2 NH2

NH2 NH2NH2 NH2

O

H

H

OO H O H

O

H

O

H

HO OH

H

O

O H

H O

H

O

O

H

OH


NOESY SPECTRUM OF C (note COSY correlations have been removed and resonances are shown as a simplified line representation – relative integrations marked off)

10 9 8 7 6 5

rel int = 1H 1H1H 1H 1H 2H

ppm

1H 1H10

98

76

54

e lin

t =1H

1H1H

1H1H

2H

ppm

1H1H

s s s br sd d d d


COSY SPECTRUM OF C:

10 9 8 7 6 5 4

rel int = 1H 1H1H 1H 1H 2H

ppm

1H 1H

109

87

65

4

rel i

nt=

1H1H

1H1H

1H2H

ppm

1H1H

s s s br sd d d d


COMPOUND D, C12H14O3 Determine the structure of D from the IR and NMR data below.

42. How many DBE has compound D? (a) 0 (b) 1 (c) 2 (d) 3 (e) 4 (f) 5 (g) 6 (h) 7 (i) 8 (j) 9

The IR spectrum contains one peak of importance at 1710 cm-1.

43. What functional group is present in compound D? (a) ester (b) aldehyde (c) acid (d) alkyne

(e) ketone (f) alkene (g) anhydride (h) alcohol

The 1H NMR (300 MHz) spectrum:

13C NMR spectrum: δ 210.5 (s), 148.0 (s), 147.8 (s), 128.5 (s), 125.1 (s), 111.5 (d), 111.3 (d), 56.1 (q), 56.0 (q), 44.2 (t), 38.6 (t), 28.1 (t). Additionally, the HMQC (135 Hz) and HMBC (10 Hz) 2D-NMR spectra are given on the following two pages to help you establish the structure.


HMQC for COMPOUND D:

1H nmr

13C (non-decoupled)

HMQC (1J=135 Hz)

44.2 t

56.0 q56.1 q

111.3 d111.5 d

128.5 s

147.8 s148.0 s

210.5 s

6.75

s

6.6

s

3.0

t

3.5

s

3.9

s

2.55

t3.85

s

28.1 t

38.6 t

125.1 s


HMBC for COMPOUND D:

1H nmr

13C (non-decoupled)

44.2 t

56.0 q56.1 q

111.3 d111.5 d

128.5 s

147.8 s148.0 s

210.5 s

6.75

s

6.6

s

3.0

t

3.5

s

3.9

s

2.55

t3.85

s

28.1 t

38.6 t

125.1 s

HMBC (3J=10 Hz)

Draw your FINAL structure for D on the ivory sheet in the space provided. [10 marks]


COMPOUND E has the formula C9H14O5. Determine the structure of E from the IR and NMR data below.

44. How many DBE are in compound E? (a) 0 (b) 1 (c) 2 (d) 3 (e) 4 (f) 5 (g) 5.5 (h) 6 (i) 6.5 (j) 7

1H NMR Spectrum [300 MHz]: The broad singlet at δ 12.05 ppm disappears when the sample is treated with D2O.

13C NMR (DEPT):

δ 209.6 (x), 174.1 (x), 40.8 (-), 32.7 (-), 18.6 (-). Selected long range HMQC (10 Hz): The pentet at 1.65 ppm shows a long range correlation to the 13C resonances at 209.6 and 174.1 ppm (only).

Draw your structure for compound E on the ivory answer sheet [12 marks]


COMPOUND F shows a molecular ion at 183 (100%) with additional peaks at 184 (11%), 185 (32%) and 186 (3%). A high resolution mass spectrum gives a value for the molecular ion of 183.082 (± 0.004). A group of fragment ions are observed at m/z = 148 and 149 (11 % of the size of the 148 mass peak). Determine the structure of COMPOUND F using the information given below. C H N O Mass C H N O Mass 4 4 0 6 148.001 8 4 0 3 148.016 4 6 1 5 148.025 8 6 1 2 148.040 4 8 2 4 148.048 8 8 2 1 148.064 4 10 3 3 148.072 8 10 3 0 148.088 5 8 0 5 148.037 9 8 0 2 148.052 5 10 1 4 148.061 9 10 1 1 148.076 5 12 2 3 148.085 9 12 2 0 148.100 6 12 0 4 148.074 10 12 0 1 148.089 6 14 1 3 148.097 10 14 1 0 148.113 7 2 1 3 148.004 11 16 0 0 148.125 7 16 0 3 148.110 12 4 0 0 148.031

45 How many DBE are present in compound F? (a) 0 (b) 1 (c) 2 (d) 3 (e) 4 (f) 5 (g) 6 (h) 7 (i) 8 (j) 9

IR spectrum: most significant peaks are at 3430 and 3355 cm-1 (both broad and strong)

1H NMR Spectrum:

13C NMR (DEPT phasing in brackets; x = absent): δ 142.8 (x), 132.0 (x), 126.3 (+), 126.2 (x), 125.2 (x), 118.8 (+), 24.1 (-), 21.7 (-), 12.8 (+), 12.0 (+)

Notable 1H-1H COSY: between the quartet at δ 2.7 and the triplet at 1.2

between the quartet at δ 2.4 and the triplet at 1.1 between the aromatic doublets

Notable 1H-1H NOESY: between the broad singlet at δ 3.7 and each triplet (1.1 and 1.2

ppm) BUT NOT between the triplets themselves.


Write the molecular formula for F on the ivory answer sheet in the place provided. [3 marks]

Draw your structure for compound F on the ivory answer sheet in the place provided [10 marks]

Workspace:


COMPOUND G shows a molecular ion at 160 (100% relative abundance) and a peak at 161 (9% rel. abundance). Significant peaks are also observed at m/e = 141 and 122 mass units. The compound is known to contain one oxygen and no nitrogens. Determine the structure of this compound using the information below.

Determine the molecular formula of COMPOUND G and write it on the ivory sheets in the space provided. [2 pts]

IR Spectrum: 2205 (medium intensity), 1690 (strong) cm-1

1H NMR:

13C{1H} NMR: δ 191.0 (t, J = 48 Hz), 100.1 (t, J = 210 Hz), 92.1 (t, J = 11 Hz), 88.0, 24.3, 23.4, 21.0, 14.1 13C DEPT: δ 191.0 (x), 100.1 (+), 92.1 (x), 88.0 (x), 24.3 (-), 23.4 (-), 21.0 (-), 14.1 (+)

Draw your structure for COMPOUND G on the ivory answer sheet [8 marks]


COMPOUND H, C7H6N2O, is NOT an aromatic compound. Use the data given below to deduce the structure of this compound.

46. How many DBE are in compound H? (a) 0 (b) 1 (c) 2 (d) 3 (e) 4 (f) 5 (g) 6 (h) 7 (i) 8 (j) 9

IR bands of note in the spectrum of H: 2230 and 2218 cm-1 (very strong and sharp)

47. What is the main functional group present in compound H? (a) 1° amine (b) 2° amine (c) 3° amine (d) 1° amide (e) 2° amide (f) ketone (g) alkyne (h) aldehyde (i) nitrile (j) alcohol

1H NMR Spectrum of H:

13C NMR Spectrum of H:

δ 155.1 (s), 142.9 (d), 115.0 (s), 108.2 (d), 105.1 (s), 100.2 (d), 55.1 (q) Establish the basic structure using 1H and 13C NMR and then use the 2D spectral data (next page) to establish the isomers (this is a bit tricky).


Short range 1H-13C HMQC correlations: δ 7.07 (1H) doublet with δ 142.9 (13C) doublet δ 5.68 (1H) doublet with δ 108.2 (13C) doublet δ 4.83 (1H) singlet with δ 100.2 (13C) doublet δ 3.85 (1H) singlet with δ 55.1 (13C) quartet

Long range 1H-13C HMQC (10 Hz) correlations:

δ 7.07 (1H) with δ 115.0 and 100.2 (13C) ONLY δ 5.68 (1H) with δ 155.1 (13C) δ 4.83 (1H) with δ 142.9 (13C) δ 3.85 (1H) with δ 155.1 (13C)

Draw the structure of compound H on the ivory answer sheet. [12 marks]

Workspace

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UNIVERSITY OF VICTORIA FINAL EXAMINATION - DECEMBER …web.uvic.ca/~chem213/Che213Final12VersB-corr.pdf · chem 213 final examination 2012 version b page 1 of 21 university of victoria