NMR Assignment.
NMR Assignment
Marks Allocated. This assessment task will count for 15% of the final subject result. A penalty of 5% for each
day or part day up to five days will be applied for late submissions without a genuine reason.
Submission procedure. To be submitted via LMS as a Microsoft Word or PDF file [Hand written pictures/scan
all also acceptable (please make sure the picture quality is good and writing is legible)] Ensure that your name
and student ID are clearly displayed on all pages (use header).
Assignment declaration. By submitting the assignment you are agreeing to the La Trobe University
Student Responsibility for Academic Integrity.
Assessment criteria. The following graduate capabilities will be assessed: Scientific presentation of
information (figures and tables), and Chemistry specific knowledge (NMR).
There are two pieces of spectral problem (Problem set 1 and Problem set 2). The total marks = 50.
Problem set 1: (25 marks)
The NMR spectra of an organic compound of molecular formula C11H10O3 was recorded on 400 MHz
instrument. Elucidate the structure based on the NMR spectra provided. NMR spectra provided includes 1H,
13C, DEPT 135, DEPT 90, COSY and HSQC (attachment 1: Problem set 1). COSY and HSQC are provided ONLY
as additional help for the assignment, inclusion in the discussion is NOT compulsory.
In your answer include:
| i) | 1H spectral details (Chemical shift values, Coupling pattern and constants with unit, Number of proton integration and assignment of peaks as aromatic/alkene/…etc any other remarks) 13C spectral details (Chemical shift values, type [C, CH2, CH3] and assignment of peaks as aromatic/alkene/…etc). Draw a proposed structure and assign 1H and 13C chemical shift values with brief justification. |
| ii) | |
| iii) |
Problem set 2: (25 marks)
In this problem you have to elucidate the structure of product B. A substrate A (structure shown in scheme 1)
which was subjected to two consecutive reactions as shown in scheme 1 below to give the product B of
molecular formula C9H14Br2. Provide the structure for Product B based on the NMR data provided (attachment
2: Problem set 2). (The 1H NMR and 13C NMR of starting substrate A has been provided for reference
purpose only).
The spectra for product B was recorded on 400 MHz instrument. Elucidate the structure based on the NMR
spectra provided: 1H, 13C, DEPT 135, DEPT 90.
In your answer include:
| i) | 1H spectral details (Chemical shift values, Coupling pattern and constants with unit, Number of proton integration and assignment of peaks as aromatic/alkene/…etc and any other remarks) 13C spectral details (Chemical shift values, type [C, CH2, CH3] and assignment). Draw a proposed structure and assign 1H and 13C chemical shift values with brief justification. |
| ii) iii) |
Marking Guide
For each problem – 25 marks (x 2)
| Criteria | Ratings | Marks | |
| Description of criterion |
15-25 pts Full Marks – complete assignment of all peaks (chemical shift), integration, splitting, coupling constant, types of carbon for 13C NMR identified, assignment; complete scientific justification provided for assignment of each peak in the final structure proposed. |
10 -15 pts – partially satisfactory peak assignment and missing justification for assignment, missing coupling constant, no final structure provided |
0 – 10 pts incomplete / unsatisfactory/ Task not done |
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