Solid State NMR capabilities:

  1. Ultra-fast magic-angle spinning (UFMAS) – Technically very challenging — the outer portion of the rotor moves close to the speed of sound — is the ability to spin faster than homogeneous linewidths in the solid-state. UFMAS has been commercially achieved in just the last few years. The benefits are very large, showing numerous and immediate applications in the literature. [1]
  2. Broadband HR-MAS + CP/MAS – The ability to characterize the dramatically varying dynamic environments at the molecular level, as occurs in nanomaterials[2],has only recently been achieved with the unique Doty DSI probe. High-resolution (HR) data can be acquired on portions of the sample that have significant flexibility in solution (even at high molecular weight) while the sample undergoes magic-angle spinning (MAS): HR-MAS. On the same sample, high-power cross-polarization (CP) enhances sensitivity of non-mobile nuclei during MAS: CP/MAS. The probe is broadbanded — enabling observation of all magnetically active nuclei — and provides very strong magic-angle gradients.
  3. Ultra-wideline NMR – Recent improvements in four areas — acquisition, spin echoes, excitation, and signal enhancement — have combined to enable studies previously believed to be impossible.[3] Ultra-wideline 14N, 35Cl, 39K, and 47Ti spectra are a few of the nuclei only recently published. The ultra-wideline spectra are very sensitive to the nucleus’ chemical environment, and thus have the ability to provide completely new information on a very broad range of materials, such as catalyst surfaces.

Catalysis Research


β-SiC is an attractive support material due to its high thermal conductivity, high chemical inertness, high mechanical strength, high stability under an oxidizing atmosphere, moderate surface area, and absence of microporosity. Hermans group treated the surface of β-SiC with oxygen and functionalized with two- and three-dimensional vanadium oxide species, creating a new family of materials with potential catalytic, photo-catalytic, and electrocatalytic applications.[4] See the Figure on right.




The molecular structure of vanadium oxide species on V/β- SiCo was investigated by using solid-state 51V MAS NMR. See the spectra on right. Samples containing ≥4 wt% V feature a single isotropic shift (denoted by an asterisk, *) centered at −616 ppm which can be attributed to the distorted trigonal bipyramidal geometry of crystalline V2O5. On the other hand, no signal is observed for samples containing ≤2 wt% V, although complementary characterization techniques suggest the presence of dispersed V sites. It has been reported that SiC can trap lattice electrons at vacancies or carbon-centered radicals. They hypothesize that paramagnetic relaxation induced by radicals interferes with the detection of resonances originating from isolated 51V nuclei (tetrahedral VO4).


Cartoon showing our hypothesized non-uniform amorphous SiOxCy layer covering β-SiC. These islands represent the effective surface area to anchor V. The vertical arrow illustrates the two steps needed to prepare V/β-SiCo.


                                          51V NMR Spectra

Sustainable Nanotechnology Research


Hamers group focus investigating the surface chemistry of carbon-based nanoparticles such as diamond nanoparticles. Their work has focused on developing methods for preparing diamond nanoparticles with ligands and polymers that confer well-defined different spatial distribution of charges, developing methods for characterizing the spatial distribution and dynamics of the nanoparticle surfaces, and ultimately understanding how the surfaces of a chemically-modified nanoparticle affect their interactions with biological systems (bacterial cells and higher organisms). The ability to confirm attachment of functionalization to high molecular weight surfaces such as nanoparticles is critical to the development of the materials. From the previous research Hamers group has conducted, NMR DOSY spectroscopy provides an excellent tool for such characterization, but nanoparticles push the boundaries of these typical studies. DOSY methods are limited by probe and gradient capabilities, and those limitations are present for larger nanoparticle systems as proven with their current research. To investigate the dynamics of the surface species, they have shown that the nuclear relaxation provides detailed methods for characterizing the dynamic motional behavior within complex materials.[5]

More recently, they extend their research by utilizing solid-state NMR to gain deeper characterization insight and to a broader class of nanomaterial systems. For example, they aim to reveal surface and subsurface chemical structure with quantitative DP 13C NMR. Furthermore, they investigate the surface and subsurface composition of carbon-based nanoparticle with different surface modification via selective 13C NMR spectra. The solid-state NMR provides significant expansion of these methods to more complex systems, and extend to different nuclear investigation.

Steps in covalent functionalization of nanodiamond with poly(allylamine hydrochloride) (PAH). PAH is depicted in red. Molecules and diamond are not drawn to scale.


Schematic illustration depicting mobile and immobile molecular segments of PAH polymer covalently linked to Diamond Nanoparticles. Figure is not drawn to scale.

Nanoparticle Interactions with Gram-Positive Bacterial Cell Surfaces

For the molecular-level understanding of such interactions, solid-state NMR is a prominent tool used by peer researchers. Pedersen group is working to understand changes in nanoparticle associate with alteration in bacterial surface chemistry, e.g., studying wildtype vs no-glucose mutant vs no-alanine mutant of the bacteria Bacillus subtilis, as observed by flow cytometry. 31P CP/MAS provides a sensitive probe into the chemical structures of these materials


[1] Edgar, Mark. “Physical methods and techniques NMR spectroscopy.” Annual Reports Section” B”(Organic Chemistry) 108 (2012): 292-315; and Jeziorna, Agata, et al. “Recent Progress in the Solid-State NMR Studies of Short Peptides: Techniques, Structure and Dynamics.” Annual Reports on NMR Spectroscopy. Vol. 83. Academic Press, 2014. 67-143.

[2] Henoumont, Céline, et al. “HR-MAS NMR Spectroscopy: an innovative tool for the characterization of iron oxide nanoparticles tracers for molecular imaging.” Analytical chemistry 87.3 (2015): 1701-1710. 

[3] Schurko, Robert W. “Ultra-wideline solid-state NMR spectroscopy.” Accounts of chemical research 46.9 (2013): 1985-1995. 

[4] Carrero, Carlos A., et al. “Supported two-and three-dimensional vanadium oxide species on the surface of β-SiC.” Catalysis Science & Technology 7.17 (2017): 3707-3714.

[5] Zhang, Yongqian, et al. “Dynamics and Morphology of Nanoparticle-Linked Polymers Elucidated by Nuclear Magnetic Resonance.” Analytical Chemistry 89.22 (2017): 12399-12407.