Nitroalkanes, nitrogen chemical shifts

Electron attracting substituents in the nearest vicinity to the nitro group tend to increase the screening constant for the latter. Nitrogen chemical shifts differentiate clearly nitroalkanes> nitroaromatics, Af-nitro and 0-nitro groups. They are also helpful in distinguishing between the true nitro structure and that of an aci-nitro compound ... 

Additivity rules were found for the nitrogen chemical shifts in nitroalkanes [491. 

The nitrogen chemical shifts of the N03 group in nitroalkanes and conjugated nitro compounds were extensively examined before 1972 (ref. Id, pp. 233-244). There is a clear /2-effect on the chemical shift in nitroalkanes (Id),... 

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