The 1H NMR spectra of three isomers with molecular formula C4H9Br are shown here. Which isomer produces which spectrum? a.

Verified step by step guidance

1. Identify the number of unique hydrogen environments in the spectrum by counting the distinct sets of peaks.
2. Note the integration values for each peak set, which indicate the relative number of hydrogens in each environment.
3. Analyze the splitting patterns of the peaks to determine the number of neighboring hydrogens for each environment.
4. Consider the chemical shift values to deduce the proximity of each hydrogen environment to electronegative atoms or groups.
5. Match the observed NMR data with the possible isomers of C4H9Br, considering the structure and symmetry of each isomer.

Key Concepts

1H NMR Spectroscopy

Proton Nuclear Magnetic Resonance (1H NMR) spectroscopy is a powerful analytical technique used to determine the structure of organic compounds. It provides information about the number of hydrogen atoms in different environments within a molecule, indicated by peaks in the spectrum. The chemical shift (measured in ppm) reveals the electronic environment of the protons, while the integration of peaks indicates the relative number of protons contributing to each signal.

Isomerism

Isomerism refers to the phenomenon where compounds have the same molecular formula but different structural or spatial arrangements. In the case of C4H9Br, there can be several isomers, including structural isomers and stereoisomers. Understanding the different types of isomers is crucial for interpreting NMR spectra, as each isomer will produce a unique pattern of peaks based on its specific hydrogen environments.

Peak Integration and Splitting Patterns

In 1H NMR, peak integration provides the ratio of hydrogen atoms contributing to each signal, while splitting patterns (multiplicity) indicate the number of neighboring hydrogen atoms. For example, a singlet indicates no neighboring protons, while a doublet suggests one neighboring proton. Analyzing these patterns helps in deducing the connectivity and arrangement of atoms in the molecule, which is essential for identifying the correct isomer corresponding to the given spectrum.