Temperature-dependent intensity anomalies in amino acid esters: weak hydrogen bonds in protected glycine, alanine and

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Determination of the Gas-phase Acidities of Oligopeptides
11:00

Determination of the Gas-phase Acidities of Oligopeptides

Published on: June 24, 2013

Katharina E Otto1, Susanne Hesse, Tobias N Wassermann

  • 1Institut für Physikalische Chemie, Universität Göttingen, Tammannstr. 6, D-37077 Göttingen, Germany.

Physical Chemistry Chemical Physics : PCCP
|June 29, 2011
PubMed

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Physical Properties of Amines

Amines with low molecular weight are usually gaseous at room temperature, while those with high molecular weight are liquid or solids in nature. Usually, low molecular weight amines have a rotten fish-like smell. Diamines typically have a pungent smell. For instance, cadaverine and putrescine, depicted in Figure 1, are two molecules responsible for decaying tissue.
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Physical Properties of Carboxylic Acid Derivatives

Intermolecular forces dictate several physical properties such as boiling points, melting points, solubilities, and so forth. They are classified into four types: ionic forces, hydrogen bonds, dipole–dipole forces, and dispersion forces. Ionic forces are the strongest, while dispersion forces are the weakest.
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Protons bonded to heteroatoms such as nitrogen and oxygen exhibit a range of chemical shift values. This is due to the varying degree of hydrogen bonding between the proton and the heteroatom in other molecules. The extent of hydrogen bonding affects the electron density around the proton, thereby giving different chemical shift values for the protons in the proton NMR spectrum.
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