Related Experiment Video

Updated: Mar 21, 2026

Line Shape Analysis of Dynamic NMR Spectra for Characterizing Coordination Sphere Rearrangements at a Chiral Rhenium Polyhydride Complex

Line Shape Analysis of Dynamic NMR Spectra for Characterizing Coordination Sphere Rearrangements at a Chiral Rhenium Polyhydride Complex

Published on: July 27, 2022

Room Temperature Chiral Discrimination in Paramagnetic NMR Spectroscopy

Alessandro Soncini¹, Simone Calvello¹

¹School of Chemistry, University of Melbourne, Parkville, Victoria 3010, Australia.

Physical Review Letters

|May 7, 2016

Summary

This study extends chiral discrimination theory to paramagnetic systems using nuclear magnetic resonance (NMR) spectroscopy. Paramagnetic NMR enables sensitive chiral detection at room temperature, significantly enhancing molecular analysis.

Area of Science:

Nuclear Magnetic Resonance (NMR) Spectroscopy
Chiral Analysis
Paramagnetism

Background:

A theory for chiral discrimination in NMR spectroscopy was previously established based on molecular electric polarization (P).
This polarization (P) rotates in a plane perpendicular to the NMR magnetic field.
Generalizing this theory to paramagnetic systems is crucial for expanding its applicability.

Purpose of the Study:

To generalize the existing theory of chiral discrimination in NMR spectroscopy to paramagnetic systems.
To predict new temperature-dependent contributions to molecular electric polarization (P).
To assess the feasibility of room-temperature chiral detection in paramagnetic molecules.

Main Methods:

Theoretical generalization of chiral discrimination principles to paramagnetic environments.
Development of ab initio calculation methods for paramagnetic complexes.
Analysis of temperature-dependent contributions to molecular electric polarization (P).

Main Results:

The theory predicts new contributions to molecular electric polarization (P) that vary with the square of inverse temperature.
Ab initio calculations on ten Dy3+ complexes at 293 K were performed.
Paramagnetic NMR chiral discrimination was found to be over 1000 times larger in strongly anisotropic paramagnetic molecules compared to diamagnetic ones.

Conclusions:

Paramagnetic systems offer significantly enhanced signals for NMR chiral discrimination.
The developed theory and calculations demonstrate the potential for room-temperature detection of chirality in paramagnetic molecules.
This advancement opens new avenues for chiral analysis in complex paramagnetic systems.

More Related Videos

Paramagnetic Relaxation Enhancement for Detecting and Characterizing Self-Associations of Intrinsically Disordered Proteins

Paramagnetic Relaxation Enhancement for Detecting and Characterizing Self-Associations of Intrinsically Disordered Proteins

Published on: September 23, 2021

High-Temperature and High-Pressure In situ Magic Angle Spinning Nuclear Magnetic Resonance Spectroscopy

High-Temperature and High-Pressure In situ Magic Angle Spinning Nuclear Magnetic Resonance Spectroscopy

Published on: October 9, 2020

Related Concept Videos

¹H NMR of Conformationally Flexible Molecules: Variable-Temperature NMR

¹H NMR of Conformationally Flexible Molecules: Variable-Temperature NMR

The axial and equatorial protons in cyclohexane can be distinguished by performing a variable-temperature NMR experiment. In this process, except for one proton, the remaining eleven protons are replaced by deuterium. The deuterium substitution avoids the possible peak splitting caused by the spin-spin coupling between the adjacent protons. The remaining proton flips between the axial and equatorial positions.

¹H NMR of Conformationally Flexible Molecules: Temporal Resolution

¹H NMR of Conformationally Flexible Molecules: Temporal Resolution

At room temperature, the chair conformer of cyclohexane undergoes rapid ring flipping between two equivalent chair conformers at a rate of approximately 105 times per second. These two chair conformers are in equilibrium. The rapid ring flipping results in the interconversion of the axial proton to an equatorial proton and an equatorial to the axial proton. Such interconversions are too rapid and cannot be detected on the NMR timescale. Hence, the NMR spectrometer cannot distinguish between the...

¹H NMR Chemical Shift Equivalence: Enantiotopic and Diastereotopic Protons

¹H NMR Chemical Shift Equivalence: Enantiotopic and Diastereotopic Protons

Replacing each alpha-hydrogen in chloroethane by bromine (or a different functional group) yields a pair of enantiomers. Such protons are called prochiral or enantiotopic and are related by a mirror plane. Enantiotopic protons are chemically equivalent in an achiral environment. Because most proton NMR spectra are recorded using achiral solvents, enantiotopic hydrogens yield a single signal.
In chiral compounds such as 2-butanol, replacing the methylene hydrogens at C3 produces a pair of...

Atomic Nuclei: Nuclear Spin State Population Distribution

Atomic Nuclei: Nuclear Spin State Population Distribution

Near absolute zero temperatures, in the presence of a magnetic field, the majority of nuclei prefer the lower energy spin-up state to the higher energy spin-down state. As temperatures increase, the energy from thermal collisions distributes the spins more equally between the two states. The Boltzmann distribution equation gives the ratio of the number of spins predicted in the spin −½ (N−) and spin +½ (N+) states.

¹H NMR: Interpreting Distorted and Overlapping Signals

¹H NMR: Interpreting Distorted and Overlapping Signals

Spin systems where the difference in chemical shifts of the coupled nuclei is greater than ten times J are called first-order spin systems. These nuclei are weakly coupled, and their chemical shifts and coupling constant can generally be estimated from the well-separated signals in the spectrum.
As Δν decreases and the signals move closer, the doublets appear increasingly distorted. The intensities of the inner lines increase at the cost of those of the outer lines as the signals are...

Chirality at Nitrogen, Phosphorus, and Sulfur

Chirality at Nitrogen, Phosphorus, and Sulfur

Chirality is most prevalent in carbon-based tetrahedral compounds, but this important facet of molecular symmetry extends to sp3-hybridized nitrogen, phosphorus and sulfur centers, including trivalent molecules with lone pairs. Here, the lone pair behaves as a functional group in addition to the other three substituents to form an analogous tetrahedral center that can be chiral.
A consequence of chirality is the need for enantiomeric resolution. While this is theoretically possible for all...

Articles linked to this work by shared authors, journal, and citation graph.

Ab initio-based determination of lanthanoid-radical exchange as visualised by inelastic neutron scattering.

Chemical science·2024

Triggering single-molecule qubit spin dynamics via non-Abelian geometric phase effects.

Physical chemistry chemical physics : PCCP·2023

Direct observation of magnetoelastic coupling in a molecular spin qubit: new insights from crystal field neutron scattering data.

Chemical science·2023

Inelastic Neutron Scattering Measurement of the Ground State Tunneling Gap in Tb and Ho Analogues of a Dy Field-Induced Single-Molecule Magnet.

Inorganic chemistry·2023

Elucidation of LMCT Excited States for Lanthanoid Complexes: A Theoretical and Solid-State Experimental Framework.

Inorganic chemistry·2022

Ab initio non-covalent crystal field theory for lanthanide complexes: a multiconfigurational non-orthogonal group function approach.

Physical chemistry chemical physics : PCCP·2022

See all related articles