Solid-State NMR Across the Periodic Table: Methods and Applications

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Solid-state NMR (SSNMR) spectroscopy is the most powerful technique for the characterization of molecular-level structure and dynamics. NMR spectra are more sensitive to structural differences and changes than any other type of spectroscopy, which makes NMR invaluable for use in chemistry, biochemistry, physics and materials science. However, its major shortcoming is its sensitivity: since NMR is a very low energy spectroscopy, it can take a long time to acquire spectra with high signal-to-noise (S/N) ratios. Until recently, it was very difficult (or in some cases impossible) to acquire NMR spectra for many of the nuclides of the elements in the periodic table (about 80%) - these are collectively known as unreceptive NMR nuclides. Indeed, one of the holy grails of NMR is to solve the problem of low sensitivity, which would open NMR experimentation to a much broader range of materials, as well as reducing the time frames of conventional NMR experiments. Recent advances in both NMR hardware and experimental design have opened up much of the periodic table to investigation by SSNMR; our research group has played a major role in the latter respect. We have designed specialized pulse sequences that are capable of sweeping large frequency bandwidths and enhancing signal, which has permitted acquisition of NMR spectra of a wide range of unreceptive nuclides. Over the next five years, we plan to take SSNMR to the next level, and design pulse sequences and acquisition methodologies, in concert with the use of state-of-the-art hardware, to open up the entire periodic table of NMR-active nuclides to study by SSNMR. Our strategy is two-tiered, featuring both fundamental methods development and applied science: 1. New methodologies and pulse sequences will be developed, to push the limits of NMR signal enhancement and to acquire NMR spectra of a variety of unreceptive nuclides. 2. These methods will be used in collaborative projects with synthetic and materials chemists from around the world. In order to rationally design new materials with desirable properties, we must have an intimate understanding of their molecular-level structure and dynamics - our new methods will provide this information. We will investigate an array of systems from the perspective of unreceptive nuclides, including active pharmaceutical ingredients (APIs; including pills, tablets, and other dosage forms), framework and porous solids (including molecular machines and heterogeneous catalysts), and nanoparticles and nanodomains (including optically active NPs used in telecommunications applications and API formulations). Our methods will have major implications for how new materials are designed and characterized; students who train under this program will be well prepared to enter academic, government, or industrial workforces, and make major contributions to the socioeconomic well-being of Canada.