(•••) In the lab, ¹H NMR is often used to verify that a reaction has worked as expected by comparing the product spectrum with what is expected. Given the ¹H NMR of the reactant shown, draw the spectrum you'd expect to see of the product that results.

Verified step by step guidance

1. Identify the functional groups present in the reactant and predict how they might change during the reaction.
2. Determine the type of reaction that is occurring (e.g., substitution, addition, elimination) and how it affects the hydrogen environment.
3. Predict the chemical shifts for the protons in the product based on the new chemical environment.
4. Consider the splitting patterns (multiplicity) for each set of equivalent protons in the product, using the n+1 rule where n is the number of neighboring protons.
5. Sketch the expected ¹H NMR spectrum of the product, indicating the chemical shifts, integration, and splitting patterns for each set of protons.

Key Concepts

Proton NMR Spectroscopy

Proton Nuclear Magnetic Resonance (¹H NMR) spectroscopy is a powerful analytical technique used to determine the structure of organic compounds. It works by measuring the magnetic environment of hydrogen atoms in a molecule, providing information about the number of hydrogen atoms, their chemical environment, and the connectivity between atoms. The resulting spectrum displays peaks that correspond to different hydrogen environments, allowing chemists to infer structural details.

Chemical Shifts

Chemical shifts in ¹H NMR refer to the position of the peaks in the spectrum, which are influenced by the electronic environment surrounding the hydrogen atoms. Different functional groups and molecular structures cause shifts in the resonance frequency of hydrogen atoms, typically measured in parts per million (ppm). Understanding chemical shifts is crucial for predicting how the product's spectrum will differ from that of the reactant, as they indicate the presence of different functional groups or changes in hybridization.

Integration and Multiplicity

Integration and multiplicity are key features of ¹H NMR spectra that provide insights into the number of hydrogen atoms and their interactions. Integration refers to the area under the peaks, which correlates with the number of protons contributing to that signal. Multiplicity, determined by the splitting of peaks, reveals how many neighboring hydrogen atoms are present, following the n+1 rule. Together, these concepts help in deducing the connectivity and arrangement of atoms in the product structure.