© 2026 DEPARTMENT OF CHEMISTRY AND CHEMICAL BIOLOGY MCMASTER UNIVERSITY
CHEMBIO 3OB3 (Winter 2026) − Assignment 3
Due Date: Thursday April 26th, 2026 at 11:59 PM
Students’ Responsibilities:
1. Answers MUST be placed in the SPACE PROVIDED.
2. Submit your completed assignment using CROWDMARK.
3. A late penalty of 1% per hour will be applied to assignments submitted after the due date. Late
assignments will ONLY be accepted up to THREE DAYS LATE.
4. All McMaster rules and procedures relating to Academic Dishonesty and Academic Integrity apply
to this assignment; all violations will result in a penalty. Students must do their own work. A
program designed to detect similar answers will be used for this exam.
5. You are responsible to complete the assignment on YOUR OWN! Solutions to assignment questions
CANNOT be completed within a group collaboration, obtained from an online tutor website or
copied from posts within a group chat.
6. This assignment can be completed: (a) on a printed copy of the assignment paper; or (b)
electronically within this assignment document. If neither a printer nor a tablet are available to you,
the assignment can be completed on plain paper; however, each question must start on a new page
and your solutions must be clear and well-organized!
7. You are responsible for ensuring that your print-out or file is complete and that all questions are
answered. This document contains 6 questions on 19 pages.
8. Use the Correlation Charts for IR, MS, NMR and UV/Vis data in Introduction to Spectroscopy (5th
Edition) by Donald Pavia for reference. A summary of important Correlation Charts has also been
posted on Avenue. Internet sources may vary slightly and cause confusion.
CHEMBIO 3OB3: Assignment 3
Q1 Q2 Q3 Q4 Q5 Q6 TOTAL
/12 /17.5 /8 /10 /12 /12 /71.5
ASSIGNMENT 3
17
© 2026 DEPARTMENT OF CHEMISTRY AND CHEMICAL BIOLOGY MCMASTER UNIVERSITY PAGE 1 OF 12
, © 2026 DEPARTMENT OF CHEMISTRY AND CHEMICAL BIOLOGY MCMASTER UNIVERSITY
Question 1. (12 marks) Outline how the following pairs of compounds could be differentiated using
heteronuclear (1H coupled to 19F or 31P) or proton (heteroatom coupled to 1H) NMR spectroscopy. Be
sure to include details (e.g., chemical shifts, multiplicities, intensities) for the most important signal(s)
in the spectra that would allow for their distinction.
Part Compound 1 Compound 2 Explanation
- Compound 1 shows a triplet of sextets (OR a
triplet of triplets of quartets) in its 31P (1H
coupled) spectrum
- Compound 2 shows a triplet of triplets in its
31P (1H coupled) spectrum
Differentiation based on the difference in
multiplicity in the 31P NMR spectrum
OR
O
O - Compound 1 shows a doublet of triplets (3JHP
P OMe
(a) P OEt and two neighbours 3JHH) and a doublet of
OH triplets (2JHP and two neighbours 3JHH) and a
OH
doublet (3JHP) for the aromatic side chain in its
1H (31P coupled) spectrum
- Compound 2 shows a doublet (2JHP) and a
doublet of quartets (3JHP and three neighbours
3JHH) and a triplet (two neighbours 3JHH) for
the aromatic side chain in its 1H (31P coupled)
spectrum
Differentiation based on the difference in
multiplicity in the 1H NMR spectrum
- Compound 1 shows a doublet of sextets (one
neighbour 2JHF and five neighbours 3JHF) in its
19F (1H coupled) spectrum
- Compound 2 shows a doublet of quartets
(one neighbour 2JHF and three neighbours 3JHF)
in its 19F (1H coupled) spectrum
OH
OH F Differentiation based on the difference in
(b) multiplicity in the 19F NMR spectrum
F
OR
- Compound 1 shows a doublet (one
neighbour 3JHH), a sextet (five neighbours
3JHH), two doublet of doublet of triplets (one
neighbour 2JHH, one neighbour 3JHF and two
neighbours 3JHH), a doublet of sextets (one
ASSIGNMENT 3
17
© 2026 DEPARTMENT OF CHEMISTRY AND CHEMICAL BIOLOGY MCMASTER UNIVERSITY PAGE 2 OF 12
, © 2026 DEPARTMENT OF CHEMISTRY AND CHEMICAL BIOLOGY MCMASTER UNIVERSITY
neighbour 2JHF and five neighbours 3JHH) and a
doublet of doublets (one neighbour 3JHF and
one neighbour 3JHH) in its 1H (19F coupled)
spectrum
- Compound 2 shows a doublet (one
neighbour 3JHH), a doublet of pentets (one
neighbour 3JHF and four neighbours 3JHH), a
doublet of quartets (one neighbour 2JHF and
three neighbours 3JHH), two doublet of doublet
of pentets (one neighbour 2JHH, one neighbour
3JHF and four neighbours 3JHH) and a triplet
(two neighbours 3JHH) in its 1H (19F coupled)
spectrum
Differentiation based on the difference in
multiplicity in the 1H NMR spectrum
- Compound 1 shows two signals in its 31P
spectrum due to the mirror plane through the
centre of this molecule
- Compound 2 shows three signals in its 31P
spectrum due to the lack of symmetry in this
molecule
Differentiation based on the total number of
signals in the 31P NMR spectrum
OR
- Compound 1 shows a triplet of pentets (two
PPh2 PPh2 neighbours 3JPP and four neighbours 3JHP) and
Ph2P PPh2 Ph2P a doublet of sextets (one neighbour 3JPP and
(c)
five neighbours 3JHP) in its 31P (1H coupled)
PPh2 spectrum
- Compound 2 shows two doublet of sextets
(one neighbour 3JPP and three neighbours 3JHP)
and a septet (four neighbours 3JHP) in its 31P
(1H coupled) spectrum
Differentiation based on the difference in
multiplicity in the 31P NMR spectrum
OR
- Compound 1 should show eight total signals
in its 1H spectrum due to the mirror plane
through the centre of this molecule
ASSIGNMENT 3
17
© 2026 DEPARTMENT OF CHEMISTRY AND CHEMICAL BIOLOGY MCMASTER UNIVERSITY PAGE 3 OF 12
CHEMBIO 3OB3 (Winter 2026) − Assignment 3
Due Date: Thursday April 26th, 2026 at 11:59 PM
Students’ Responsibilities:
1. Answers MUST be placed in the SPACE PROVIDED.
2. Submit your completed assignment using CROWDMARK.
3. A late penalty of 1% per hour will be applied to assignments submitted after the due date. Late
assignments will ONLY be accepted up to THREE DAYS LATE.
4. All McMaster rules and procedures relating to Academic Dishonesty and Academic Integrity apply
to this assignment; all violations will result in a penalty. Students must do their own work. A
program designed to detect similar answers will be used for this exam.
5. You are responsible to complete the assignment on YOUR OWN! Solutions to assignment questions
CANNOT be completed within a group collaboration, obtained from an online tutor website or
copied from posts within a group chat.
6. This assignment can be completed: (a) on a printed copy of the assignment paper; or (b)
electronically within this assignment document. If neither a printer nor a tablet are available to you,
the assignment can be completed on plain paper; however, each question must start on a new page
and your solutions must be clear and well-organized!
7. You are responsible for ensuring that your print-out or file is complete and that all questions are
answered. This document contains 6 questions on 19 pages.
8. Use the Correlation Charts for IR, MS, NMR and UV/Vis data in Introduction to Spectroscopy (5th
Edition) by Donald Pavia for reference. A summary of important Correlation Charts has also been
posted on Avenue. Internet sources may vary slightly and cause confusion.
CHEMBIO 3OB3: Assignment 3
Q1 Q2 Q3 Q4 Q5 Q6 TOTAL
/12 /17.5 /8 /10 /12 /12 /71.5
ASSIGNMENT 3
17
© 2026 DEPARTMENT OF CHEMISTRY AND CHEMICAL BIOLOGY MCMASTER UNIVERSITY PAGE 1 OF 12
, © 2026 DEPARTMENT OF CHEMISTRY AND CHEMICAL BIOLOGY MCMASTER UNIVERSITY
Question 1. (12 marks) Outline how the following pairs of compounds could be differentiated using
heteronuclear (1H coupled to 19F or 31P) or proton (heteroatom coupled to 1H) NMR spectroscopy. Be
sure to include details (e.g., chemical shifts, multiplicities, intensities) for the most important signal(s)
in the spectra that would allow for their distinction.
Part Compound 1 Compound 2 Explanation
- Compound 1 shows a triplet of sextets (OR a
triplet of triplets of quartets) in its 31P (1H
coupled) spectrum
- Compound 2 shows a triplet of triplets in its
31P (1H coupled) spectrum
Differentiation based on the difference in
multiplicity in the 31P NMR spectrum
OR
O
O - Compound 1 shows a doublet of triplets (3JHP
P OMe
(a) P OEt and two neighbours 3JHH) and a doublet of
OH triplets (2JHP and two neighbours 3JHH) and a
OH
doublet (3JHP) for the aromatic side chain in its
1H (31P coupled) spectrum
- Compound 2 shows a doublet (2JHP) and a
doublet of quartets (3JHP and three neighbours
3JHH) and a triplet (two neighbours 3JHH) for
the aromatic side chain in its 1H (31P coupled)
spectrum
Differentiation based on the difference in
multiplicity in the 1H NMR spectrum
- Compound 1 shows a doublet of sextets (one
neighbour 2JHF and five neighbours 3JHF) in its
19F (1H coupled) spectrum
- Compound 2 shows a doublet of quartets
(one neighbour 2JHF and three neighbours 3JHF)
in its 19F (1H coupled) spectrum
OH
OH F Differentiation based on the difference in
(b) multiplicity in the 19F NMR spectrum
F
OR
- Compound 1 shows a doublet (one
neighbour 3JHH), a sextet (five neighbours
3JHH), two doublet of doublet of triplets (one
neighbour 2JHH, one neighbour 3JHF and two
neighbours 3JHH), a doublet of sextets (one
ASSIGNMENT 3
17
© 2026 DEPARTMENT OF CHEMISTRY AND CHEMICAL BIOLOGY MCMASTER UNIVERSITY PAGE 2 OF 12
, © 2026 DEPARTMENT OF CHEMISTRY AND CHEMICAL BIOLOGY MCMASTER UNIVERSITY
neighbour 2JHF and five neighbours 3JHH) and a
doublet of doublets (one neighbour 3JHF and
one neighbour 3JHH) in its 1H (19F coupled)
spectrum
- Compound 2 shows a doublet (one
neighbour 3JHH), a doublet of pentets (one
neighbour 3JHF and four neighbours 3JHH), a
doublet of quartets (one neighbour 2JHF and
three neighbours 3JHH), two doublet of doublet
of pentets (one neighbour 2JHH, one neighbour
3JHF and four neighbours 3JHH) and a triplet
(two neighbours 3JHH) in its 1H (19F coupled)
spectrum
Differentiation based on the difference in
multiplicity in the 1H NMR spectrum
- Compound 1 shows two signals in its 31P
spectrum due to the mirror plane through the
centre of this molecule
- Compound 2 shows three signals in its 31P
spectrum due to the lack of symmetry in this
molecule
Differentiation based on the total number of
signals in the 31P NMR spectrum
OR
- Compound 1 shows a triplet of pentets (two
PPh2 PPh2 neighbours 3JPP and four neighbours 3JHP) and
Ph2P PPh2 Ph2P a doublet of sextets (one neighbour 3JPP and
(c)
five neighbours 3JHP) in its 31P (1H coupled)
PPh2 spectrum
- Compound 2 shows two doublet of sextets
(one neighbour 3JPP and three neighbours 3JHP)
and a septet (four neighbours 3JHP) in its 31P
(1H coupled) spectrum
Differentiation based on the difference in
multiplicity in the 31P NMR spectrum
OR
- Compound 1 should show eight total signals
in its 1H spectrum due to the mirror plane
through the centre of this molecule
ASSIGNMENT 3
17
© 2026 DEPARTMENT OF CHEMISTRY AND CHEMICAL BIOLOGY MCMASTER UNIVERSITY PAGE 3 OF 12
