2- Nitropropane COSY spectrum

Nitropropane. To see what type of information a COSY spectram may provide, we shall consider several examples of increasing complexity. The first is the COSY spectrum of 2-nitropropane. In this simple molecule, we expect to observe coupling between the protons on the two methyl groups and the proton at the methine position. 

Isopentyl Acetate. In practice, we would not require a COSY spectram to fully interpret the NMR spectrum of 2-nitropropane. The preceding analysis illustrated how to interpret a COSY spectrum, using a simple, easy-to-understand example. A more interesting example is the COSY spectrum of isopentyl acetate (Fig. 10.13). 

The COSY spectrum of 1-nitropropane is shown in Figure 15.40. Cross peak X shows that the and protons are coupled, and cross peak Y shows that the Hj and protons are coupled. Notice that the two triangles in the figure have a common vertex, since the protons are coupled to both the and protons. 

The COSY spectrum of 1-nitropropane. A COSY spectrum identifies coupled protons, such as Hg/H/, and H /Hc in 1 -nitropropane. 

Figure 13.45 shows the proton COSY spectrum of 1-nitropropane. Account for the appearance of off-diagonal peaks in the spectrum. 

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