Question

Use the Proton NMR Characteristic Table to answer the following question.

What is the predicted chemical shift (ppm) range for an amino hydrogen?

Answer 1

The provided data does not explicitly give the chemical shift for amino hydrogens but typically, aliphatic amino hydrogens appear between 0.5 - 5 ppm and could be approximately 5 - 8 ppm if part of an amide.

Step-by-step explanation:

The predicted chemical shift (ppm) range for an amino hydrogen in an NMR spectrum varies, but in the context of the provided data which focuses on aromatic and anomeric proton shifts rather than aliphatic amines, the range is not explicitly given. Amino hydrogens on aliphatic amines typically appear between 0.5 - 5 ppm; however, if the amino group is part of an amide, the range may be approximately 5 - 8 ppm. It is important to note that specific shifts can be influenced by many factors, including the presence of electronegative atoms nearby, hydrogen bonding, and the solvent used during the NMR experiment.

Answer 2

The amino hydrogen protons in NMR tend to appear in the range of 0.5 to 5 ppm, with hydrogen-bonded or deshielded amide N-H protons resonating closer to 5 to 9 ppm.

Step-by-step explanation:

The predicted chemical shift range for an amino hydrogen in proton NMR would not typically be found in a table for aromatic or anomeric protons as amino hydrogens do not resonate in those chemical shift regions. Amino group protons generally appear in the chemical shift range of approximately 0.5 to 5 ppm depending on their environment. Amino hydrogens bonded to an sp3 hybridized nitrogen, such as in aliphatic amines, will typically resonate around 1 to 3 ppm. In the case of molecules containing amide bonds, the N-H protons of the amide group usually exhibit chemical shifts around 5 to 9 ppm due to involvement in hydrogen bonding and resonance effects which influence shielding and deshielding within the molecule.