NMR methods/theory
Understanding Dynamic Exchange using Variable Field NMR
Jean-Paul Heeb - @jpheeb
We have been able to reliably chemical shift scale NMR spectra from 500 to 50 MHz for small molecule systems undergoing dynamic exchange (atropisomers). Using this, we can observe coalescence at lower temperatures, plot Eyring graphs, and estimate activation parameters with smaller uncertainties than VTNMR alone.
Electrophoretic NMR Reveals Migrating Solvation Structures in Li-ion Battery Electrolytes
David Halat - @davidhalat
We report 1H, 19F, and 7Li electrophoretic NMR (eNMR) measurements, which directly quantify ion and solvent motion under an electric field, to reveal solvent motion driven by cation–solvent coordination in Li-ion battery electrolytes. We further corroborate molecular dynamics solvation motifs by rationalizing concentration-dependent 1H NMR shifts through DFT calculations.
The Search for a Universal qNMR Standard
Jared Scott Wood - @jaredscottwood
Quantitative NMR (qNMR) is a robust technique used in a variety of chemical applications due to its numerous analytical advantages. We report a selectively-tunable standard for 1H/19F quantitation and its vast potential in qNMR analyses.
High-pressure, high-temperature MAS NMR for catalysis science
Nicholas Jaegers - @njaegers
Accurate descriptions of chemical interactions proceeding on catalytic surfaces necessitate characterization under conditions relevant to catalysis to avoid challenges imposed by environment-dependent catalyst properties. As a non-destructive tool, NMR is well-suited to study chemical interactions in catalysis; we describe methods of MAS NMR for systems at high pressure and temperature.
17O nuclear spin relaxation and its dependence on concentrated electrolyte system
Chengtong Zhang - @zhang_chengtong
The effects of different ion compositions and concentrations on the 17O relaxation time were investigated and some principles of ion-water interactions were deduced. Notably, we find that the water diffusion and solution viscosity correlate with 17O relaxation rate of water when different electrolytes were dissolved in D2O.
NMR spectroscopy -Introduction
Zamir Shekh - @ProfZamirShekh
Nuclear magnetic resonance, or NMR, is a physical phenomenon that occurs when atomic nuclei are exposed to a specific frequency of electromagnetic radiation and a magnetic energy level resonance transition. One can obtain the NMR spectrum by identifying the absorption signals. It helps to investigate the architectures of molecules quantitatively based on the locations, intensities, and fine structure of resonance peaks. The size of the molecules of interest ranges from small chemical molecules to middle-sized biological molecules and even certain macromolecules like proteins and nucleic acids.
Dynamic nuclear polarization by two-pulse phase modulation
Venkata SubbaRao Redrouthu - @rvsubbarao
The coherent transfer of electron spin polarization to nuclei by means of a microwave pulse sequence is a promising new approach to enhancing the sensitivity of solid-state nuclear magnetic resonance (NMR). The development of pulse sequences for dynamic nuclear polarization (DNP) of bulk nuclei is far from complete, as is the understanding of what makes a good DNP sequence. In this context, we introduce a new sequence, termed Two-Pulse Phase Modulation (TPPM) DNP. We provide a general theoretical description for electron–proton polarization transfer by periodic DNP pulse sequences and find it in excellent agreement with numerical simulations.
Towards Pulsed DNP at 100 Tesla
Alexander Barnes - @MagnetXander
I have a dream. I dream of hundreds and thousands of 100 Tesla Pulsed Dynamic Nuclear Polarization NMR spectrometers sitting on bench-tops and equipped with magic angle spinning spheres spinning a million times a second. To make this dream a reality, talented, ambitious, and dedicated scientists at the ETH Zurich are developing new magnets, microwave technology, and MAS instrumentation. Let me tell you about it.
The power of 19F-NMR: peptide-membrane binding is not that basic!
Tran Thanh Tam Pham - @tammyphamily
My research focuses on a hormone, Apelin, important in forming new blood vessels and progressing chronic illnesses. It is not uncommon for peptides like Apelin to bind membrane before receptor-binding. Using 19F-Nuclear Magnetic Resonance, I characterize this binding suggesting a mechanism for Apelin that highlights membrane role in therapeutic delivery.
Baseline Correction in NMR Spectroscopy
Ruoru Ma - @ruoruma
In NMR, the baseline distortion usually appears as a curve displaced from the ideal flat line at Zero intensity. Corrections of these distortions is a necessary step in NMR spectra data processing to ensure the peak assignment as well as concentration prediction. The automatic baseline distortion correction method was reviewed.
Design of a probe at 60MHz
Baudouin DILLMANN - @dillmann_bd
The development of low field NMR has led to significant advancements in scientific research. Frugale, although not low-cost, offers sufficient performance for various applications. These scientific instruments play a crucial role in physics education, providing hands-on experience. Moreover, they are indispensable for scientific progress, facilitating breakthroughs across diverse disciplines.
Investigation of Intrinsic Linewidths in NV-detected 13C NMR at 4.2 Tesla
Yuhang Ren - @yuhangre
The nitrogen-vacancy (NV) center in diamond has enabled widespread study of nanoscale NMR. We present a 13C NV-detected NMR at 4.2 Tesla and show that the method can capture the intrinsic NMR spectrum. This work demonstrates a clear path to high resolution NV-detected NMR at high magnetic fields.
Testing limits of homonuclear decoupling at fast MAS
Mrudula Nikam - @mrudula_nikam
Proton is a preferred nucleus for detection, due to its higher gyromagnetic ratio. 1H-1H dipolar couplings are very strong due to the same reason. It causes broad peaks and reduced coherence lifetimes, even under very fast MAS frequencies (>60 kHz). A combination of fast MAS and pulsed homonuclear decoupling sequences can extend 1H coherence times to values higher than those possible with only one of these techniques. However, it is unclear if these two techniques can be combined to give an additive effect, especially at these fast MAS frequencies. I will discuss Phase Modulated Lee-Goldburg (PMLG) and TIlted Magic-Echo Sandwich with zero degree sandwich pulse (TIMES0) schemes for 1H-1H homonuclear decoupling which we have used to enhance the coherence lifetimes of protons in a uniformly labelled model peptide using both windowed and non-windowed schemes. We will suggest regimes in which these sequences can be applied to extend 1H coherence times by a factor of 2-3 over MAS alone, making the use of sequences such as INEPT feasible in non-deuterated proteins.
DNP in Multiradicals with Sub-Nanometer Electron-Electron Distances
Raj Chaklashiya - @RajChaklashiya
Multielectron Dynamic Nuclear Polarization (ME-DNP) is proposed to be a promising mechanism to achieve NMR signal enhancements due to its low microwave power requirement and scalability to high magnetic field. Here we explore experimentally and theoretically how to achieve this using a designed multielectron geometry of spatially proximal narrow-line radicals.
Solid-state NMR revealed peculiar phosphonate in velvet worm slime
Alexandre Poulhazan - @AlexPoulhazan
Velvet worms are fascinating animals that have a peculiar way to hunt. They eject a translucent liquid, the slime, that quickly forms sticky fibers trapping their preys. In addition to exciting recyclability of this natural glue, this slime has been characterized here by MAS-DNP and NMR, detecting unprecedented phosphonate-rich molecules.
DOSY automation
Adolfo Botana - @botana
Diffusion-Ordered SpectroscopY is an NMR method that requires performing a number of steps to acquire a good quality dataset. Here we demonstrate an approach to automatically setup the experiment parameters by prediction the diffusion behaviour using the SEGWE equation and automatically evaluating the presence of convection.
Improving XiX DNP with optimal control
Shebha Anandhi Jegadeesan - @AnandhiJ61993
We use quantum optimal control algorithm to improve XiX DNP. The optimized DNP sequences with initial pulse lengths of 12 and 20 ns gave enhancements 2.4 and 1.6 times greater than XiX DNP, respectively. The challenges and anomaly between the numerical simulations and experiments will be addressed in the poster.
NMR spectroscopy in the light of supercritical fluid technologies
Konstantin Belov - @SCFsci
Determination of the predominant conformation of small molecules of drug in solution is one of the fundamental tasks of modern pharmaceutical and physical chemistry. Our research group "Fluid State NMR" has proposed a number of technical and methodological ways to solve this problem in the supercritical fluid environment.
Probing Multidimensional Metal Halides at the X-site using 79/81Br NMR, NQR, and DFT
Riley Hooper - @RileyHooper97
Metal halide materials offer optoelectronic tunability through compositional variation but feature complicated phase behaviour and dynamic properties, with the halide site being integral to such behaviour. We use bromine NMR, NQR, and DFT to study a series of cesium lead bromides and extend these insights to the analogous Cl/I materials.
Chemical Shift Imaging NMR for Probing Bacterial-Mammalian Crosstalk in the Human Large Intestine
Trey Koev - @TTKoev
Chemical shift imaging NMR allows us to exploit a naturally occurring gradient of commensal bacteria, mucosa and large intestinal colonocytes. Probing the metabolic crosstalk between bacteria and colonocytes in healthy and diseases (cancer) cell set-ups allows us to probe differences in the cell-cell communication on a molecular level, potentially enabling the development of novel treatment avenues for colorectal pathologies.
Nuclear Magnetic Resonance spectroscopy technique for Identification of Designer Drugs
Annwesha Mazumdar - @Annwesha9
It’s a challenging task to detect the metabolites of designer drugs in the body. NMR spectroscopy is one of the validating techniques for its utility of metabolic fingerprinting of various designer drugs and has opened a new horizon in forensics. This paper highlights the recent developments of Nuclear Magnetic Resonance spectroscopy applied for the Forensic identification of various designer drugs.
Deuterium Relaxation as a Probe to investigate Conformational Analysis of Beta-lactoglobulin (β-lg)
Sakshi Bhagat - @sakszi
Being the most dynamic component of majority of biological processes solvent plays a crucial role in changing the protein's conformation in the system. The structural evolution of protein in various media, such as co-solvents, electrolytes, and others indicates existence of various intra- and intermolecular interactions that are responsible for maintaining protein stability. In the present study we focussed on the spin-lattice relaxation of deuterium nuclei present in co-solvents deciphering conformational changes in β-LG at variable concentration of co-solvent at a neutral pH. Β-LG is a milk protein with 162 Amino acids and is found abundantly in milk and is one the most extensively studied β-sheet protein. Presently, tri-fluorethanol (TFE) and Acetonitrile (ACN) are the two organic solvents under investigation. Spin-lattice relaxation rates of 2H nuclei can provide solitary insights into time dependent conformational fluctuation of β-LG from beta sheet to the α-helix structure.
Determination of the predominant conformation of Arbidol solvates in scCO2 by NMR
Eventova Varvara - @evarvara24
Crystalline forms of medicinal compounds in the form of crystalline solvates have increased solubility in water and can be used to improve therapeutic properties. When obtaining solvates, the choice of solvent is important. In this work, the predominant conformations of arbidol in scCO2+2% DMSO-d6 were determined by NMR and X-Ray methods. The results showed the promise of using scCO2 as an alternativevto organic solvents.
Exploring the Effect of Aerogel on Mefenamic Acid Structure and Properties
Valentina Sobornova - @VSobornova7121
The effect of mefenamic acid on the physicochemical and sorption properties of aerogel was studied. 1H and 13C MAS, T1-T2 RRCOSY and 1H-1H NOESY NMR experiments were carried out to study the conformational state of mefenamic acid and its effect on the aerogel structure. The results show that the group fraction of conformer groups of mefenamic acid changes by 53% in the presence of aerogel.
Off-the-Shelf Gd(NO3)3 as an Efficient High-Spin Metal Ion Polarizing Agent for Magic Angle Spinning Dynamic Nuclear Polarisation
Daniel Cheney - @DanielCheney14
Paramagnetic metal ion complexes have been demonstrated as an alternative to traditionally-used biradical polarising agents for DNP, which are typically not commercially available. Based on this, we have introduced Gd(NO3)3 as an easily accessible and inexpensive “off-the-shelf” polarising agent, providing significant sensitivity enhancements for 13C and 15N.
Minimizing the Perturbation of the Applied Magnetic Field by Optimizing Solid-State NMR Probe Structures
Jasmin Schoenzart - @SchoenzartJas
In this work we present ways to minimize the perturbation of the applied magnetic field by optimizing solid-state NMR probe structures. This is achieved by a combination of simulations and experiments, which take susceptibilities of all parts in the NMR probe into account to then study the net effect upon the sample. Based on those results, modifications to NMR probes can be made, to minimize unwanted contributions. The smaller the perturbation of the applied magnetic field, the narrower the observed possible linewidth and the higher the resolution of the experiment.
Probing NV and SiV charge state dynamics using high-voltage nanosecond pulse and photoluminescence spectral analysis
Artur Pambukhchyan - @APambukhch86933
Nitrogen-vacancy (NV) and silicon-vacancy (SiV) color defects in diamond carry multiple charge states that possess various electronic, optical and spin properties important for quantum technology. We demonstrate that high-voltage pulses shift chemical potential and convert the charge states of NV and SiV centers with the transition rates of ∼ MHz.