Question

What is the wavenumber range for the aromatic region?

Answer 1

The wavenumber range for the aromatic region is 3.45 x 10³ cm-¹ to 3.85 x 10³ cm-¹.

Step-by-step explanation:

The aromatic region in a UV-Vis spectrum refers to the wavelength range where aromatic compounds absorb light. In this case, the absorbance peak for aromatic amino acids occurs between 260 nm to 290 nm. Additionally, these compounds emit light maximally from about 290 nm to about 350 nm. Therefore, the wavenumber range for the aromatic region can be calculated by converting the wavelengths to wavenumbers using the formula:

Wavenumber (cm-¹) = 1 / Wavelength (cm)

By substituting in the given wavelength range, we get:
Wavenumber range = 1 / 290 nm to 1 / 260 nm

Wavenumber range = 3.45 x 10³ cm-¹ to 3.85 x 10³ cm-¹

Answer 2

The wavenumber range for the aromatic region in infrared spectroscopy is generally between 1400 to 1600 cm-1. This encompasses the characteristic peaks due to the conjugated bond system in aromatic compounds.

Step-by-step explanation:

The wavenumber range for the aromatic region typically falls within 1400 to 1600 cm-1. However, for more detailed interpretations, such as in the case of aromatic amino acids, the absorbance peak is observed between 260 nm to 290 nm when considering ultraviolet-visible (UV-Vis) spectroscopy. This correlates to the infrared spectroscopy (IR spectroscopy) range as wavenumbers can be approximately translated from wavelengths.

When dealing with IR spectroscopy, aromatic compounds are characterized by distinctive absorbance due to their conjugated system of bonds. These absorbances typically fall within the mentioned wavenumber range. It is also important to note influences from other functional groups which may shift these ranges slightly or introduce additional peaks.