The University of Southampton
University of Southampton Institutional Repository

New methods for nitrogen-14 solid state NMR

New methods for nitrogen-14 solid state NMR
New methods for nitrogen-14 solid state NMR
Nitrogen is one of the most abundant elements. It plays a significant role in different scientific disciplines, like materials science, chemistry, biochemistry and pharmaceutical chemistry. Most NMR studies of nitrogen have been performed on samples enriched with 15N. To avoid enrichment and overcome the problem of using NMR where isotopic enrichment is not feasible, NMR of 14N that has 99.6% natural abundance is a viable alternative. However, the 14N spin quantum number 1 and high quadrupolar interactions lead to a few challenges for NMR investigation. Recently, two approaches appeared which overcome the complications associated to the first order quadrupolar line broadening, namely indirect detection using vicinal nuclei and overtone transition. Paper 1 describes a novel version of HMQC experiments, which requires the application of a moderate RF field to the 14N nucleus to correlate the 14N with a 13C ‘spy’ nucleus, which provides good sensitivity on natural abundance and labelled materials. In addition, overtone 14N NMR spectroscopy is a promising route for the direct detection of 14N signals with good spectral resolution. Overtone NMR is the main topic of my research. To overcome the poor efficiency of the overtone transition, polarization transfer techniques have been implemented. Papers 2 and 4 present respectively polarization transfer methods from 1H to the 14N overtone using symmetry-based R-sequences and cross polarization methods. Signal enhancements of 6.7 and 2 have been obtained when cross polarization methods and symmetry-based R-sequences are used respectively. Paper 3 shows results obtained with the DOR (double rotation) technique to reduce 14N overtone linewidth, with 14N overtone spectra with linewidth reduced by nearly one order of magnitude. Analysis of the results has been facilitated through the use of a new simulation strategy for 14N overtone NMR spectroscopy of spinning samples, using Spinach library.
Haies, Ibraheem
f27584b7-74d7-4d07-af1d-3cd9333cf101
Haies, Ibraheem
f27584b7-74d7-4d07-af1d-3cd9333cf101
Carravetta, Marina
1b12fa96-4a6a-4689-ab3b-ccc68f1d7691

(2015) New methods for nitrogen-14 solid state NMR. University of Southampton, Chemistry, Doctoral Thesis, 143pp.

Record type: Thesis (Doctoral)

Abstract

Nitrogen is one of the most abundant elements. It plays a significant role in different scientific disciplines, like materials science, chemistry, biochemistry and pharmaceutical chemistry. Most NMR studies of nitrogen have been performed on samples enriched with 15N. To avoid enrichment and overcome the problem of using NMR where isotopic enrichment is not feasible, NMR of 14N that has 99.6% natural abundance is a viable alternative. However, the 14N spin quantum number 1 and high quadrupolar interactions lead to a few challenges for NMR investigation. Recently, two approaches appeared which overcome the complications associated to the first order quadrupolar line broadening, namely indirect detection using vicinal nuclei and overtone transition. Paper 1 describes a novel version of HMQC experiments, which requires the application of a moderate RF field to the 14N nucleus to correlate the 14N with a 13C ‘spy’ nucleus, which provides good sensitivity on natural abundance and labelled materials. In addition, overtone 14N NMR spectroscopy is a promising route for the direct detection of 14N signals with good spectral resolution. Overtone NMR is the main topic of my research. To overcome the poor efficiency of the overtone transition, polarization transfer techniques have been implemented. Papers 2 and 4 present respectively polarization transfer methods from 1H to the 14N overtone using symmetry-based R-sequences and cross polarization methods. Signal enhancements of 6.7 and 2 have been obtained when cross polarization methods and symmetry-based R-sequences are used respectively. Paper 3 shows results obtained with the DOR (double rotation) technique to reduce 14N overtone linewidth, with 14N overtone spectra with linewidth reduced by nearly one order of magnitude. Analysis of the results has been facilitated through the use of a new simulation strategy for 14N overtone NMR spectroscopy of spinning samples, using Spinach library.

PDF
imh_thesis_31Aug.pdf - Other
Download (30MB)

More information

Published date: 31 July 2015
Organisations: University of Southampton, Chemistry

Identifiers

Local EPrints ID: 382902
URI: http://eprints.soton.ac.uk/id/eprint/382902
PURE UUID: c0d5c47e-c506-4a27-97ac-cde1ca14b17b
ORCID for Marina Carravetta: ORCID iD orcid.org/0000-0002-6296-2104

Catalogue record

Date deposited: 05 Nov 2015 14:37
Last modified: 19 Sep 2018 04:01

Export record

Download statistics

Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.

View more statistics

Atom RSS 1.0 RSS 2.0

Contact ePrints Soton: eprints@soton.ac.uk

ePrints Soton supports OAI 2.0 with a base URL of http://eprints.soton.ac.uk/cgi/oai2

This repository has been built using EPrints software, developed at the University of Southampton, but available to everyone to use.

We use cookies to ensure that we give you the best experience on our website. If you continue without changing your settings, we will assume that you are happy to receive cookies on the University of Southampton website.

×