Skip to main content
Ch. 14 - NMR Spectroscopy
Bruice - Organic Chemistry 8th Edition
Bruice8th EditionOrganic ChemistryISBN: 9780135213711Non è quello che usi tu?Cambia libro di testo
Capitolo 14, Problema 2b

What strength magnetic field is required when a 500-MHz instrument is used for 1H NMR?

Guida verificata passo dopo passo
1
Understand the relationship between the magnetic field strength (B₀) and the resonance frequency (ν) in NMR spectroscopy. The equation is given by: ν = (γ * B₀) / (2π), where γ is the gyromagnetic ratio for the nucleus being studied (for 1H, γ = 2.675 x 10^8 rad T⁻¹ s⁻¹).
Rearrange the equation to solve for the magnetic field strength (B₀): B₀ = (2π * ν) / γ.
Substitute the given resonance frequency (ν = 500 MHz = 500 x 10^6 Hz) into the equation. Ensure the units are consistent.
Use the gyromagnetic ratio for 1H (γ = 2.675 x 10^8 rad T⁻¹ s⁻¹) in the equation.
Perform the calculation to determine the magnetic field strength (B₀) in Tesla (T).

Risposta video verificata per un problema simile:

Questa soluzione video è stata consigliata dai nostri tutor come utile per risolvere questo problema.
Durata del video:
7m

Concetti chiave

Ecco i concetti essenziali che devi comprendere per rispondere correttamente alla domanda.

Nuclear Magnetic Resonance (NMR)

Nuclear Magnetic Resonance (NMR) 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), which resonate at specific frequencies when placed in a magnetic field. The frequency of the resonance is directly related to the strength of the magnetic field applied, allowing chemists to infer information about molecular structure and dynamics.
Video consigliato:
04:00
13C NMR General Features

Larmor Frequency

The Larmor frequency is the frequency at which a nucleus precesses in a magnetic field. It is determined by the equation ω = γB, where ω is the angular frequency, γ is the gyromagnetic ratio specific to the nucleus, and B is the magnetic field strength. For 1H NMR, the Larmor frequency is crucial for determining the required magnetic field strength for a given operating frequency, such as 500 MHz.
Video consigliato:
16:47
Common IR Frequencies

Magnetic Field Strength Calculation

To calculate the magnetic field strength required for a specific NMR frequency, one can rearrange the Larmor equation to B = ω/γ. By substituting the frequency (in radians per second) and the gyromagnetic ratio for hydrogen, one can determine the necessary magnetic field strength. This relationship is fundamental in designing NMR instruments and understanding their operational parameters.
Video consigliato:
04:37
Draw all of the monochlorination products and calculate percentage yields.