My research group specializes in methods for designing and applying solid-state NMR experiments for unreceptive nuclei across the periodic table. Unreceptive NMR nuclei are classified as such due to:
- low gyromagnetic ratio (i.e., low Larmor frequency)
- low natural abundance
- large quadrupolar interactions (NQM, EFG tensor)
- large chemical shift anisotropy (CSA)
- paramagnetic broadening
- long relaxation times (long T1 constants!)
- dilution of the nuclide of interest
- any combination of the above factors
Here is a periodic table giving a qualitative picture of spin-1/2 nuclei that are classified as receptive or unreceptive. Gradient colours indicate that these nuclei can be classified in multiple categories.
Here is a similar periodic table for quadrupolar nuclei (i.e., nuclear spins > 1/2). Note, that all integer-spin nuclei are considered to be unreceptive.
We have had a lot of success acquiring SSNMR spectra of isotopes of a variety of elements from across the periodic table. In the picture below, the elements in green indicate that we've run experiments on one or more isotopes, yellow indicates that we could do these but the right project has not come along yet, and the garnet boxes indicate future target elements/isotopes that we hope to study at the MagLab over the next few years. In particular, the 35.2 T (1500 MHz) Series Connected Hybrid system will be one of the tools we use to conduct these studies.
For an interactive frequency map and listing of a lot of NMR-active nuclei, check out Alexej Jerschow's excellent page.
Here are some examples of ultra-wideline solid-state NMR (UW NMR) spectra acquired at the MagLab on our high-field instruments:
Field-stepped 35Cl WURST-CPMG NMR of N-chlorosuccinimide acquired on the 36T SCH
1H-103Rh SSNMR of Rh(acac)3 at 21.1 T (900 MHz)
55Mn WURST-CPMG NMR of CpMn(CO)3 at 18.8 T (800 MHz)
1H-59Co BRAIN-CP/WURST-CPMG NMR of [Co(NH3)5Cl][Cl2]
Check out the publications page for papers on many nuclei from across the Periodic Table!