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oai:figshare.com:article/33847021 2026-09-16T12:30:01Z portal_1197 item_type_3 month_year_09_2026

Data for Optimisation of 1H PMLG homonuclear decoupling at 60 kHz MAS to enable 15N-1H through-bond heteronuclear correlation solid-state NMR spectroscopy Jacqueline Tognetti (24963298) W. Trent Franks (1334424) Józef Romuald Lewandowski (24964381) Steven P. Brown (1296819) Nuclear magnetic resonance spectroscopy Solid state chemistry Migrated from ePrints The Lee-Goldburg condition for homonuclear decoupling in 1H magic-angle spinning (MAS) solid-state NMR sets the angle θ corresponding to arctan of the ratio of the rf nutation frequency, ν1, to the rf offset, to be the magic angle, θm, equal to tan-1(√2) = 54.7⁰. At 60 kHz MAS, we report enhanced decoupling compared to MAS alone in a 1H spectrum of 15N-glycine with PMLG5 at θ = 30⁰ for a ν1 of ~100 kHz at a 1H Larmor frequency, ν0, of 500 MHz and 1 GHz, corresponding to a high chemical shift scaling factor (CS) of 0.82. At 1 GHz, we also demonstrate enhanced decoupling compared to 60 kHz MAS alone for a lower ν1 of 51 kHz, i.e., a case where the nutation frequency is less than the MAS frequency, with θ = 18⁰, λCS = 0.92. The ratio of the rotor period to the decoupling cycle time, Ψ = τr/ τc, is in the range 0.53 to 0.61. Windowed PMLG5 decoupling using the optimised parameters for a ν1 of ~100 kHz also gives good performance in a 1H spin-echo experiment, enabling implementation in a 1H-detected 15N-1H cross polarisation (CP)-refocused INEPT heteronuclear correlation NMR experiment. Specifically, initial 15N transverse magnetisation as generated by 1H-15N CP is transferred back to 1H using a refocused INEPT pulse sequence employing windowed 1H decoupling. Such an approach ensures the observation of through-bond N-H connectivities. For 15N-glycine, while the CP-refocused INEPT experiment has a lower sensitivity (~50%) as compared to a double CP experiment (with a 200 μs 15N to 1H CP contact time), there is selectivity for the directly bonded NH3+ moiety, while intensity is observed for the CH2 1H resonances in the double CP experiment. Two-dimensional 15N-1H correlation MAS NMR spectra are presented for the dipeptide β-AspAla and the pharmaceutical cimetidine at 60 kHz MAS, both at natural isotopic abundance. For the dipeptide β-AspAla, different build-up dependence on the first spin-echo duration is observed for the NH and NH3+ moieties demonstrating that the experiment could be used to distinguish resonances for different NHx groups.<br><br>The data have been collected in a single folder in the following order: PMLG optimization 1H 1D GHz data 2D 1H-1H correlation 15N-1H CP- Refocused INEPT experiment bAsp-Ala experiments Cimetdine experiments 2022-07-28T00:00:00Z Dataset Dataset 10.82444/warw.33847021.v1 https://figshare.com/articles/dataset/Data_for_Optimisation_of_1H_PMLG_homonuclear_decoupling_at_60_kHz_MAS_to_enable_15N-1H_through-bond_heteronuclear_correlation_solid-state_NMR_spectroscopy/33847021 CC BY 4.0