(•) Draw the signal for the following multiplicities. What is the ratio of peaks within each signal? (f) septet

Verified step by step guidance

1. Understand that a septet in NMR spectroscopy refers to a signal split into seven peaks.
2. Recall that the splitting pattern in NMR is determined by the n+1 rule, where n is the number of neighboring protons. For a septet, n = 6.
3. Recognize that the ratio of peaks in a septet follows Pascal's triangle, specifically the 6th row, which is 1:6:15:20:15:6:1.
4. Visualize the septet as a series of seven peaks with the intensity ratio of 1:6:15:20:15:6:1, where the middle peak is the tallest.
5. Consider the chemical environment and neighboring protons that could lead to such a splitting pattern in a molecule, such as a proton adjacent to a group of six equivalent protons.

Key Concepts

Multiplicity in NMR Spectroscopy

Multiplicity refers to the number of peaks in an NMR signal, which indicates the number of neighboring hydrogen atoms (protons) that influence the signal. This is determined by the n+1 rule, where n is the number of adjacent protons. For example, a signal that appears as a septet indicates that there are six neighboring protons.

Septet

A septet is a specific type of multiplicity in NMR spectroscopy characterized by seven peaks. This pattern arises when a hydrogen atom is coupled to six equivalent neighboring protons. The intensity ratio of the peaks in a septet follows the binomial distribution, typically represented as 1:6:15:20:15:6:1.

Peak Ratios in NMR

The peak ratios in NMR signals provide insight into the relative number of protons contributing to each peak. For a septet, the ratio of the peak heights is derived from the coefficients of the binomial expansion, which for a septet is 1:6:15:20:15:6:1. Understanding these ratios helps in deducing the structure and environment of the protons in the molecule.