Deuteron-proton isotope correlation spectroscopy at high magnetic fields

Area of Science:

• Solid-state Nuclear Magnetic Resonance (NMR) Spectroscopy
• Materials Science
• Pharmaceutical Analysis

Background:

• Characterizing complex molecular structures and interactions in solid materials is crucial for drug development and material science.
• Traditional NMR methods can be time-consuming and challenging for analyzing partially deuterated compounds.
• Isotopic enrichment offers a pathway to enhance NMR signal detection and structural elucidation.

Purpose of the Study:

• To develop and present a rapid cross-polarization 2H-1H isotope correlation spectroscopy (CP-iCOSY) approach.
• To demonstrate the capability of this method for characterizing deuterated amino acids, pharmaceutical compounds, and solid formulations.
• To compare the efficiency of different CP sequences for 2D 1H-2H correlation spectra acquisition.

Main Methods:

• Utilized high magnetic field (28.2 T) and fast magic-angle spinning (MAS) for rapid 2H NMR spectra detection.
• Employed a two-dimensional (2D) 2H-1H CP-iCOSY experiment to probe local structures and through-space interactions.
• Compared conventional spin-lock and rotor-echo-short-pulse-irradiation RESPIRATIONCP sequences for 2D 1H-2H correlation spectra.
• Analyzed partially deuterated L-histidine·HCl·H2O and dopamine.HCl samples.

Main Results:

• Achieved rapid detection of 2H NMR spectra within seconds to minutes.
• The RESPIRATIONCP sequence enabled 2D peak detection at lower contact times compared to conventional CP.
• Successfully detected 2H-1H pairs separated by distances greater than 4 Å, indicating potential for characterizing packing interactions.
• Results were corroborated by NMR crystallography analysis using the Gauge-Including Projector Augmented-Wave (GIPAW) approach.

Conclusions:

• The presented CP-iCOSY approach offers a powerful and efficient method for characterizing deuterated compounds.
• This technique is valuable for elucidating local structures and packing interactions in pharmaceutical and material science applications.
• The use of RESPIRATIONCP sequences enhances the speed and sensitivity of 2D 1H-2H correlation spectroscopy.