Lab 2: Infra-Red (IR) - Nuclear Magnetic Resonance (NMR) Exercises In Molecular Spectroscopy - Structural Determination Organic Chemistry II
October 30, 2012
For the purposes of this lab, the chemical formula will be given, and the degrees of unsaturation can be calculate from the formula (2C+2)-(H+Hal-N)/2. The degrees of unsaturation will give clues as to the structure. A double bond, as well as a ring will have one degree of unsaturation each, while a double bond will have two. All of these added will give a total of degrees and can eliminate some possibilities that other data would suggest if there are not enough degrees for those structures. Mass Spectrometry is a fast procedure that can give the structure of a molecule, but breaking everything apart is tedious, and it is used mainly to find the molecular weight of a molecule since the last and highest peak gives a signal in an equivalent of grams to mole of the molecule. Infra-red spectroscopy (IR) will present peaks in places characteristic of certain functional groups, and can show if a group is present, although there are some instances where a functional group will not show up. Nuclear magnetic resonance (NMR), specifically H-NMR, will show all hydrogen in a molecule. The peaks will be shifted in characteristic ways, but will also be shifted due to their proximity to an electronegative atom. For this lab, integration of peaks will be given, which gives the amount of hydrogen in a peak, and the splitting patterns of each peak can give how much hydrogen is attached to adjacent atoms (Manrique, 2012). Objective
To determine the structure of organic compounds (Manrique, 2012). Hypothesis
By analyzing the mass spec, IR and NMR graphs, the structure of a molecule can be found. Experiment
Lab 2 Handout
Analyze each graph and deduce the structural formula of each molecule.
For the molecule with chemical...
Cited: Manrique, C. (2012). Lab 2: Infra-Red (IR)- Nuclear Magnetic Resonance (NMR) Exercises In Molecular Spectroscopy- Structural Determination. Organic Chemistry Lab 2. Dallas. Tx.
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