Determination of sample temperature in unstable static fields by combining solid-state (79)Br and (13)C NMR

Area of Science:

• Solid-state Nuclear Magnetic Resonance (NMR) spectroscopy.
• Materials science and physical chemistry.

Background:

• Accurate temperature calibration is crucial for solid-state NMR.
• Maintaining static magnetic field stability is challenging during measurements.
• Isotropic chemical shifts are often used for temperature calibration, but are sensitive to field variations.

Purpose of the Study:

• To develop a reliable method for temperature calibration in solid-state NMR.
• To overcome the limitations of magnetic field instability in temperature monitoring.
• To accurately determine the temperature dependence of bromine-79 (79Br) resonances.

Main Methods:

• Utilizing carbon-13 (13C) resonance to monitor fluctuations in the static magnetic field.
• Employing a novel approach to subtract resonance frequency changes caused by magnetic field variations.
• Recovering the true temperature-dependent signal of the 79Br resonance.

Main Results:

• Successfully isolated the temperature dependence of the 79Br resonance.
• Demonstrated a simple yet effective method to correct for magnetic field drift.
• Provided a more accurate way to assess temperature in solid-state NMR experiments.

Conclusions:

• The proposed method allows for accurate temperature calibration despite magnetic field instability.
• This technique enhances the reliability of solid-state NMR studies requiring precise temperature control.
• The findings are applicable to various solid-state NMR experiments involving 79Br.