The Experts below are selected from a list of 150237 Experts worldwide ranked by ideXlab platform
Michael P Hanrahan - One of the best experts on this subject based on the ideXlab platform.
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probing o h bonding through proton detected 1h 17o double resonance solid state NMR spectroscopy
Journal of the American Chemical Society, 2019Co-Authors: Michael P Hanrahan, Scott L Carnahan, Bryan J Lampkin, Pranjali Naik, Igor I Slowing, Brett VanvellerAbstract:The ubiquity of oxygen in organic, inorganic, and biological systems has stimulated the application and development of 17O Solid-State NMR spectroscopy as a probe of molecular structure and dynamics. Unfortunately, 17O Solid-State NMR experiments are often hindered by a combination of broad NMR signals and low sensitivity. Here, it is demonstrated that fast MAS and proton detection with the D-RINEPT pulse sequence can be generally applied to enhance the sensitivity and resolution of 17O Solid-State NMR experiments. Complete 2D 17O → 1H D-RINEPT correlation NMR spectra were typically obtained in less than 10 h from less than 10 mg of material, with low to moderate 17O enrichment (less than 20%). Two-dimensional 1H–17O correlation Solid-State NMR spectra allow overlapping oxygen sites to be resolved on the basis of proton chemical shifts or by varying the mixing time used for 1H–17O magnetization transfer. In addition, J-resolved or separated local field (SLF) blocks can be incorporated into the D-RINEPT pu...
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probing o h bonding through proton detected 1h 17o double resonance solid state NMR spectroscopy
Journal of the American Chemical Society, 2019Co-Authors: Michael P Hanrahan, Scott L Carnahan, Bryan J Lampkin, Pranjali Naik, Igor I Slowing, Brett VanvellerAbstract:The ubiquity of oxygen in organic, inorganic, and biological systems has stimulated the application and development of 17O Solid-State NMR spectroscopy as a probe of molecular structure and dynamic...
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sensitivity enhanced 207pb solid state NMR spectroscopy for the rapid non destructive characterization of organolead halide perovskites
Chemistry of Materials, 2018Co-Authors: Michael P Hanrahan, Aaron J. Rossini, Long Men, Bryan A. Rosales, Javier VelaAbstract:Organolead halide and mixed halide perovskites (CH3NH3PbX3, CH3NH3PbX3–nYn, X and Y = Cl–, Br–, or I–) are promising materials for photovoltaics and optoelectronic devices. 207Pb Solid-State NMR spectroscopy has previously been applied to characterize phase segregation and halide ion speciation in mixed halide perovskites. However, NMR spectroscopy is an insensitive technique that often requires large sample volumes and long signal averaging periods. This is especially true for mixed halide perovskites, which give rise to extremely broad 207Pb Solid-State NMR spectra. Here, we quantitatively compare the sensitivity of the various Solid-State NMR techniques on pure and mixed halide organolead perovskites and demonstrate that both fast MAS and DNP can provide substantial gains in NMR sensitivity for these materials. With fast MAS and proton detection, high signal-to-noise ratio two-dimensional (2D) 207Pb–1H heteronuclear correlation (HETCOR) NMR spectra can be acquired in less than half an hour from only ca...
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proton detection of mas solid state NMR spectra of half integer quadrupolar nuclei
Solid State Nuclear Magnetic Resonance, 2017Co-Authors: Amrit Venkatesh, Michael P Hanrahan, Aaron J. RossiniAbstract:Fast magic angle spinning (MAS) and proton detection has found widespread application to enhance the sensitivity of Solid-State NMR experiments with spin-1/2 nuclei such as 13C, 15N and 29Si, however, this approach is not yet routinely applied to half-integer quadrupolar nuclei. Here we have investigated the feasibility of using fast MAS and proton detection to enhance the sensitivity of Solid-State NMR experiments with half-integer quadrupolar nuclei. The previously described dipolar hetero-nuclear multiple quantum correlation (D-HMQC) and dipolar refocused insensitive nuclei enhanced by polarization transfer (D-RINEPT) pulse sequences were used for proton detection of half-integer quadrupolar nuclei. Quantitative comparisons of signal-to-noise ratios and the sensitivity of proton detected D-HMQC and D-RINEPT and direct detection spin echo and quadrupolar Carr-Purcell Meiboom-Gill (QCPMG) Solid-State NMR spectra, demonstrate that one dimensional proton detected experiments can provide sensitivity similar to or exceeding that obtainable with direct detection QCPMG experiments. 2D D-HMQC and D-RINEPT experiments provide less sensitivity than QCPMG experiments but proton detected 2D hetero-nuclear correlation Solid-State NMR spectra of half-integer nuclei can still be acquired in about the same time as a 1D spin echo spectrum. Notably, the rarely used D-RINEPT pulse sequence is found to provide similar, or better sensitivity than D-HMQC in some cases. Proton detected D-RINEPT benefits from the short longitudinal relaxation times (T1) normally associated with half-integer quadrupolar nuclei, it can be combined with existing signal enhancement methods for quadrupolar nuclei, and t1-noise in the indirect dimension can easily be removed by pre-saturation of the 1H nuclei. The rapid acquisition of proton detected 2D HETCOR Solid-State NMR spectra of a range of half-integer quadrupolar nuclei such as 17O, 27Al, 35Cl and 71Ga is demonstrated.
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rapid acquisition of wideline mas solid state NMR spectra with fast mas proton detection and dipolar hmqc pulse sequences
Physical Chemistry Chemical Physics, 2016Co-Authors: Michael P Hanrahan, Aaron J. Rossini, Martin M ThuoAbstract:The Solid-State NMR spectra of many NMR active elements are often extremely broad due to the presence of chemical shift anisotropy (CSA) and/or the quadrupolar interaction (for nuclei with spin I > 1/2). These NMR interactions often give rise to wideline Solid-State NMR spectra which can span hundreds of kHz or several MHz. Here we demonstrate that by using fast MAS, proton detection and dipolar hetero-nuclear multiple-quantum (D-HMQC) pulse sequences, it is possible to rapidly acquire 2D spectra which correlate 1H chemical shifts to the indirectly detected wideline MAS powder patterns of dipolar coupled hetero-nuclei. The D-HMQC pulse sequence enables broadband excitation of the wideline hetero-nuclear NMR spectrum and provides higher sensitivity by detecting the narrower and more sensitive 1H NMR signal. This approach is demonstrated for the rapid acquisition of 2D 1H detected 195Pt Solid-State NMR spectra of cisplatin and transplatin and the 71Ga Solid-State NMR spectrum of a self-assembled Ga coordination polymer of unconfirmed structure. This approach should be broadly applicable for the rapid acquisition of wideline MAS Solid-State NMR spectra of moderately abundant NMR nuclei.
Aaron J. Rossini - One of the best experts on this subject based on the ideXlab platform.
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sensitivity enhanced 207pb solid state NMR spectroscopy for the rapid non destructive characterization of organolead halide perovskites
Chemistry of Materials, 2018Co-Authors: Michael P Hanrahan, Aaron J. Rossini, Long Men, Bryan A. Rosales, Javier VelaAbstract:Organolead halide and mixed halide perovskites (CH3NH3PbX3, CH3NH3PbX3–nYn, X and Y = Cl–, Br–, or I–) are promising materials for photovoltaics and optoelectronic devices. 207Pb Solid-State NMR spectroscopy has previously been applied to characterize phase segregation and halide ion speciation in mixed halide perovskites. However, NMR spectroscopy is an insensitive technique that often requires large sample volumes and long signal averaging periods. This is especially true for mixed halide perovskites, which give rise to extremely broad 207Pb Solid-State NMR spectra. Here, we quantitatively compare the sensitivity of the various Solid-State NMR techniques on pure and mixed halide organolead perovskites and demonstrate that both fast MAS and DNP can provide substantial gains in NMR sensitivity for these materials. With fast MAS and proton detection, high signal-to-noise ratio two-dimensional (2D) 207Pb–1H heteronuclear correlation (HETCOR) NMR spectra can be acquired in less than half an hour from only ca...
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Sensitivity-Enhanced 207Pb Solid-State NMR Spectroscopy for the Rapid, Non-Destructive Characterization of Organolead Halide Perovskites
2018Co-Authors: Michael P. Hanrahan, Long Men, Bryan A. Rosales, Javier Vela, Aaron J. RossiniAbstract:Organolead halide and mixed halide perovskites (CH3NH3PbX3, CH3NH3PbX3–nYn, X and Y = Cl–, Br–, or I–) are promising materials for photovoltaics and optoelectronic devices. 207Pb Solid-State NMR spectroscopy has previously been applied to characterize phase segregation and halide ion speciation in mixed halide perovskites. However, NMR spectroscopy is an insensitive technique that often requires large sample volumes and long signal averaging periods. This is especially true for mixed halide perovskites, which give rise to extremely broad 207Pb Solid-State NMR spectra. Here, we quantitatively compare the sensitivity of the various Solid-State NMR techniques on pure and mixed halide organolead perovskites and demonstrate that both fast MAS and DNP can provide substantial gains in NMR sensitivity for these materials. With fast MAS and proton detection, high signal-to-noise ratio two-dimensional (2D) 207Pb–1H heteronuclear correlation (HETCOR) NMR spectra can be acquired in less than half an hour from only ca. 4 μL of perovskite material. Modest relayed DNP enhancements on the order of 1 to 20 were obtained for perovskites. The cryogenic temperatures (110 K) used for DNP experiments also provide a significant boost in sensitivity. Consequently, it was possible to obtain the 207Pb Solid-State NMR spectrum of a 300 nm thick model thin film of CH3NH3PbI3 in 34 h by performing Solid-State NMR experiments with a sample temperature of 110 K. This result demonstrates the possibility of using NMR spectroscopy for characterization of perovskite thin films
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proton detection of mas solid state NMR spectra of half integer quadrupolar nuclei
Solid State Nuclear Magnetic Resonance, 2017Co-Authors: Amrit Venkatesh, Michael P Hanrahan, Aaron J. RossiniAbstract:Fast magic angle spinning (MAS) and proton detection has found widespread application to enhance the sensitivity of Solid-State NMR experiments with spin-1/2 nuclei such as 13C, 15N and 29Si, however, this approach is not yet routinely applied to half-integer quadrupolar nuclei. Here we have investigated the feasibility of using fast MAS and proton detection to enhance the sensitivity of Solid-State NMR experiments with half-integer quadrupolar nuclei. The previously described dipolar hetero-nuclear multiple quantum correlation (D-HMQC) and dipolar refocused insensitive nuclei enhanced by polarization transfer (D-RINEPT) pulse sequences were used for proton detection of half-integer quadrupolar nuclei. Quantitative comparisons of signal-to-noise ratios and the sensitivity of proton detected D-HMQC and D-RINEPT and direct detection spin echo and quadrupolar Carr-Purcell Meiboom-Gill (QCPMG) Solid-State NMR spectra, demonstrate that one dimensional proton detected experiments can provide sensitivity similar to or exceeding that obtainable with direct detection QCPMG experiments. 2D D-HMQC and D-RINEPT experiments provide less sensitivity than QCPMG experiments but proton detected 2D hetero-nuclear correlation Solid-State NMR spectra of half-integer nuclei can still be acquired in about the same time as a 1D spin echo spectrum. Notably, the rarely used D-RINEPT pulse sequence is found to provide similar, or better sensitivity than D-HMQC in some cases. Proton detected D-RINEPT benefits from the short longitudinal relaxation times (T1) normally associated with half-integer quadrupolar nuclei, it can be combined with existing signal enhancement methods for quadrupolar nuclei, and t1-noise in the indirect dimension can easily be removed by pre-saturation of the 1H nuclei. The rapid acquisition of proton detected 2D HETCOR Solid-State NMR spectra of a range of half-integer quadrupolar nuclei such as 17O, 27Al, 35Cl and 71Ga is demonstrated.
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rapid acquisition of wideline mas solid state NMR spectra with fast mas proton detection and dipolar hmqc pulse sequences
Physical Chemistry Chemical Physics, 2016Co-Authors: Michael P Hanrahan, Aaron J. Rossini, Martin M ThuoAbstract:The Solid-State NMR spectra of many NMR active elements are often extremely broad due to the presence of chemical shift anisotropy (CSA) and/or the quadrupolar interaction (for nuclei with spin I > 1/2). These NMR interactions often give rise to wideline Solid-State NMR spectra which can span hundreds of kHz or several MHz. Here we demonstrate that by using fast MAS, proton detection and dipolar hetero-nuclear multiple-quantum (D-HMQC) pulse sequences, it is possible to rapidly acquire 2D spectra which correlate 1H chemical shifts to the indirectly detected wideline MAS powder patterns of dipolar coupled hetero-nuclei. The D-HMQC pulse sequence enables broadband excitation of the wideline hetero-nuclear NMR spectrum and provides higher sensitivity by detecting the narrower and more sensitive 1H NMR signal. This approach is demonstrated for the rapid acquisition of 2D 1H detected 195Pt Solid-State NMR spectra of cisplatin and transplatin and the 71Ga Solid-State NMR spectrum of a self-assembled Ga coordination polymer of unconfirmed structure. This approach should be broadly applicable for the rapid acquisition of wideline MAS Solid-State NMR spectra of moderately abundant NMR nuclei.
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dynamic nuclear polarization enhanced solid state NMR spectroscopy of functionalized metal organic frameworks
Angewandte Chemie, 2012Co-Authors: Aaron J. Rossini, Moreno Lelli, Alexandre Zagdoun, Jerome Canivet, Sonia Aguado, Olivier Ouari, Paul Tordo, Melanie Rosay, Werner E Maas, Christophe CopéretAbstract:Dynamic nuclear polarization (DNP) is applied to enhance the signal of Solid-State NMR spectra of metal-organic framework (MOF) materials. The signal enhancement enables the acquisition of high-quality 1D 13C Solid-State NMR spectra, 2D 1H-13C dipolar HETCOR and 1D 15N Solid-State NMR spectra with natural isotopic abundance in experiment times on the order of minutes.
Lyndon Emsley - One of the best experts on this subject based on the ideXlab platform.
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High-resolution H-1 Solid-State NMR spectroscopy using windowed LG4 homonuclear dipolar decoupling
Israel Journal of Chemistry, 2014Co-Authors: Meghan E. Halse, Judith Schlagnitweit, Lyndon EmsleyAbstract:We investigate the optimal implementation of windowed LG4 decoupling for the direct acquisition of high-resolution 1H Solid-State NMR spectra in the moderate magic-angle spinning regime (ωr
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high resolution solid state NMR spectroscopy in surface organometallic chemistry access to molecular understanding of active sites of well defined heterogeneous catalysts
Chemical Society Reviews, 2008Co-Authors: Frederic Blanc, Christophe Copéret, Anne Lesage, Lyndon EmsleyAbstract:Recent advances in solid state NMR spectroscopy have made possible the understanding of surface species and active sites of heterogeneous catalysts at a molecular level. This tutorial review describes solid state NMR spectroscopy, what are the possible techniques to obtain high resolution and 2D spectra (structural information), and what are their applications in the context of well-defined heterogeneous catalysts prepared by surface organometallic chemistry.
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spectral editing in solid state NMR using scalar multiple quantum filters
Journal of Magnetic Resonance, 2001Co-Authors: Dimitris Sakellariou, Anne Lesage, Lyndon EmsleyAbstract:In this paper we describe the use of heteronuclear scalar couplings in Solid-State NMR in order to generate multiple-quantum filtering (MQF) pulse sequences. These sequences can be used to edit CP/MAS spectra according to carbon multiplicity. Analytic expressions for the intensity of the MQF signals are obtained using the standard product operator formalism. Experiments that demonstrate the technique are shown in powder samples of camphor and a tripeptide.
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homonuclear dipolar decoupling in solid state NMR using continuous phase modulation
Chemical Physics Letters, 2000Co-Authors: Dimitris Sakellariou, Anne Lesage, Paul Hodgkinson, Lyndon EmsleyAbstract:Abstract We present a theoretical framework for the use of continuously phase modulated radio-frequency pulses for homonuclear decoupling in Solid-State NMR. Within this framework, we have derived new families of decoupling sequences using numerical optimization. One of these sequences is tested experimentally on an ordinary organic solid, and its performance is compared with standard multiple-pulse sequences.
Scott L Carnahan - One of the best experts on this subject based on the ideXlab platform.
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probing o h bonding through proton detected 1h 17o double resonance solid state NMR spectroscopy
Journal of the American Chemical Society, 2019Co-Authors: Michael P Hanrahan, Scott L Carnahan, Bryan J Lampkin, Pranjali Naik, Igor I Slowing, Brett VanvellerAbstract:The ubiquity of oxygen in organic, inorganic, and biological systems has stimulated the application and development of 17O Solid-State NMR spectroscopy as a probe of molecular structure and dynamics. Unfortunately, 17O Solid-State NMR experiments are often hindered by a combination of broad NMR signals and low sensitivity. Here, it is demonstrated that fast MAS and proton detection with the D-RINEPT pulse sequence can be generally applied to enhance the sensitivity and resolution of 17O Solid-State NMR experiments. Complete 2D 17O → 1H D-RINEPT correlation NMR spectra were typically obtained in less than 10 h from less than 10 mg of material, with low to moderate 17O enrichment (less than 20%). Two-dimensional 1H–17O correlation Solid-State NMR spectra allow overlapping oxygen sites to be resolved on the basis of proton chemical shifts or by varying the mixing time used for 1H–17O magnetization transfer. In addition, J-resolved or separated local field (SLF) blocks can be incorporated into the D-RINEPT pu...
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probing o h bonding through proton detected 1h 17o double resonance solid state NMR spectroscopy
Journal of the American Chemical Society, 2019Co-Authors: Michael P Hanrahan, Scott L Carnahan, Bryan J Lampkin, Pranjali Naik, Igor I Slowing, Brett VanvellerAbstract:The ubiquity of oxygen in organic, inorganic, and biological systems has stimulated the application and development of 17O Solid-State NMR spectroscopy as a probe of molecular structure and dynamic...
Brett Vanveller - One of the best experts on this subject based on the ideXlab platform.
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probing o h bonding through proton detected 1h 17o double resonance solid state NMR spectroscopy
Journal of the American Chemical Society, 2019Co-Authors: Michael P Hanrahan, Scott L Carnahan, Bryan J Lampkin, Pranjali Naik, Igor I Slowing, Brett VanvellerAbstract:The ubiquity of oxygen in organic, inorganic, and biological systems has stimulated the application and development of 17O Solid-State NMR spectroscopy as a probe of molecular structure and dynamics. Unfortunately, 17O Solid-State NMR experiments are often hindered by a combination of broad NMR signals and low sensitivity. Here, it is demonstrated that fast MAS and proton detection with the D-RINEPT pulse sequence can be generally applied to enhance the sensitivity and resolution of 17O Solid-State NMR experiments. Complete 2D 17O → 1H D-RINEPT correlation NMR spectra were typically obtained in less than 10 h from less than 10 mg of material, with low to moderate 17O enrichment (less than 20%). Two-dimensional 1H–17O correlation Solid-State NMR spectra allow overlapping oxygen sites to be resolved on the basis of proton chemical shifts or by varying the mixing time used for 1H–17O magnetization transfer. In addition, J-resolved or separated local field (SLF) blocks can be incorporated into the D-RINEPT pu...
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probing o h bonding through proton detected 1h 17o double resonance solid state NMR spectroscopy
Journal of the American Chemical Society, 2019Co-Authors: Michael P Hanrahan, Scott L Carnahan, Bryan J Lampkin, Pranjali Naik, Igor I Slowing, Brett VanvellerAbstract:The ubiquity of oxygen in organic, inorganic, and biological systems has stimulated the application and development of 17O Solid-State NMR spectroscopy as a probe of molecular structure and dynamic...
