Sketch the following spectra that would be obtained for 2-chloroethanol: a. The 1H NMR spectrum for an anhydrous sample of the alcohol.

Verified step by step guidance

1. Identify the different types of hydrogen atoms in the molecule 2-chloroethanol. There are three types: the hydrogen on the hydroxyl group (OH), the hydrogen on the carbon adjacent to the chlorine (CH2Cl), and the hydrogen on the carbon adjacent to the hydroxyl group (CH2OH).
2. Consider the chemical environment of each type of hydrogen. The hydrogen on the hydroxyl group is typically deshielded due to the electronegative oxygen, causing it to appear downfield in the spectrum. The hydrogen atoms on the CH2Cl group are next to a chlorine atom, which is also electronegative and will shift these hydrogens slightly downfield. The hydrogens on the CH2OH group are affected by the adjacent oxygen but to a lesser extent than the hydroxyl hydrogen.
3. Determine the splitting patterns for each type of hydrogen. The hydrogens on the CH2 groups are likely to be split by the adjacent CH2 group's hydrogens. The hydroxyl hydrogen typically appears as a singlet.
4. Estimate the chemical shift values based on typical NMR data. Hydroxyl hydrogens generally appear around 2-5 ppm, hydrogens on a CH2 group next to an electronegative atom like chlorine typically appear around 3-4 ppm, and hydrogens on a CH2 group next to an oxygen (like in CH2OH) typically appear around 3.5-4.5 ppm.
5. Sketch the spectrum by plotting the estimated chemical shift values on the horizontal axis (ppm) and indicating the splitting patterns at each chemical shift. Label each peak with the corresponding hydrogen type (OH, CH2Cl, CH2OH).

Key Concepts

Nuclear Magnetic Resonance (NMR) Spectroscopy

NMR spectroscopy is a powerful analytical technique used to determine the structure of organic compounds. It relies on the magnetic properties of certain nuclei, such as hydrogen-1 (1H), to provide information about the number of hydrogen atoms, their environment, and how they are connected in a molecule. The resulting spectrum displays peaks that correspond to different hydrogen environments, allowing chemists to infer structural details.

Chemical Shifts

Chemical shifts in NMR spectroscopy refer to the variation in resonance frequency of nuclei due to their electronic environment. In 1H NMR, chemical shifts are measured in parts per million (ppm) and provide insight into the types of hydrogen atoms present. For 2-chloroethanol, the presence of the chlorine atom and the hydroxyl group will influence the chemical shifts of the hydrogen atoms, leading to distinct peaks in the spectrum.

Integration and Multiplicity

Integration and multiplicity are key features in interpreting NMR spectra. Integration refers to the area under the peaks, which indicates the relative number of hydrogen atoms contributing to each signal. Multiplicity describes the splitting of NMR signals due to neighboring hydrogen atoms, following the n+1 rule, where n is the number of adjacent protons. Understanding these concepts is essential for accurately deducing the structure of 2-chloroethanol from its 1H NMR spectrum.