Hyperpolarized Laplace NMR

Abstract

Laplace nuclear magnetic resonance (NMR), dealing with NMR relaxation and diffusion experiments, reveals details of molecular motion and provides chemical resolution complementary to NMR spectra. Laplace NMR has witnessed a great progress in past decades due to the development of methodology and signal processing, and it has lots of extremely interesting applications in various fields, including chemistry, biochemistry, geology, archaeology, and medicine. The aim of this minireview is to give a pedagogically oriented overview of Laplace NMR. It does not provide a full literature review of the field, but, instead, it elucidate the benefits and features of Laplace NMR methods through few selected examples. The minireview describes also recent progress in multidimensional Laplace NMR and Laplace inversion methods. Furthermore, the potential of modern hyperpolarization methods as well as ultrafast approach to increase the sensitivity and time-efficiency of the Laplace NMR experiments is highlighted.

Effect of natural weathering on water absorption and pore size distribution in thermally modified wood determined by nuclear magnetic resonance

“…For unmodified ash, the distribution at 295 K contained three peaks, which were considered to arise from bound water in cell walls (peak 1) and free water in lumens of fibers and parenchyma (peak 5) and vessels (peak 6, Almeida et al 2007;Gao et al 2015). However, peak 5 split into 3 and 2 peaks after Thermo S and Thermo D modifications, probably due to the socalled pearling artefact arising from the Laplace inversion (Telkki 2018). This might also imply that the exchange between free water in different sizes and positions of fiber is slow.…”

Mechanisms and Beyond: Elucidation of Fluxional Dynamics by Exchange NMR Spectroscopy

“…Low-temperature 1 H-1 HE XSY studies and crossover experiments revealed that the observed equilibration was due to ion-pair rearrangement and ligand flip, with as ignificantly lower barrierf or the ligand flip process. Te lkki and co-workers [131] demonstrated the utility of Laplace NMR spectroscopy [132] for studying chemical exchange. Laplace-transformation LNMR gives information on relaxation T 2 :i onic liquid 81 hast wo different phases,o ne slower than the other.A2D T 2 -T 2 domain experiment showed exchange of ions between the phases, with an "ion lifetime" of 0.92 sf or the fast phase and 55 sf or the slow phase.…”

Ultrafast Laplace NMR to study metal–ligand interactions in reversible polarisation transfer from parahydrogen

“…Even though ultrafast Laplace NMR experiments can measure relaxation and diffusion parameters with experiment times reduced by 1 to 3 orders of magnitude compared to Fourier transform NMR, or standard Laplace NMR, they still suffer from low thermal polarisation. 2 Therefore, hyperpolarised Laplace NMR can be highly beneficial to boost the signal intensity of single scan measurements. 2,20,21,36 For the first time we report the combination of Laplace NMR with the SABRE hyperpolarisation technique.…”

“…This has been used to develop ultrafast Laplace NMR experiments [17][18][19] which reduce the experiment time by one to four orders of magnitude compared to traditional approaches. 2 Consequently, ultrafast LNMR has been used to study molecular dynamics in a range of chemical systems including porous materials, 17,20 cellular metabolites, 21 and surfactant aggregates. 22 Nevertheless, these measurements can be limited by the low sensitivity of MR which is derived from perturbations of very small population differences across closely spaced nuclear spin energy levels.…”