Solid State Nuclear Magnetic Resonance

Spectrometers    Probes & Capabilities

Spectrometers

Solid state NMR facilities at the Magnet Lab can offer user a variety of superconducting magnets with fields strengths as high as 900 MHz. The MagLab is home to the world’s largest 900 MHz superconducting magnet built in 2004 by our own Magnet Science and Technology department.

In Tallahassee 900 MHz 830 MHz 720 MHz 6001 MHz 6002 MHz 400 MHz 300 MHz

In Gainesville 750 MHz 600 MHz 500 MHz

Bruker spectrometers are used with all systems above, with the exception of the Varian spectrometer at 720 MHz system.

In addition, 25 tesla resistive and 45 tesla hybrid magnets are also available for selected solid state experiments.

Probes and Capabilities

Biological Solids MAS NMR

Triple-resonance Low-E 3.2 mm ¹H–X–Y MAS probes are available at 900 and 600 MHz. The low-E technology was developed at the MagLab to provide maximum sensitivity of detection with minimum heating of biological samples. A suite of 2D and 3D MAS experiments allow for spectral assignment and structural elucidation of ¹³C/¹⁵N labeled proteins.

900 MHz Low-E 3.2 mm MAS 1H–X–Y probe 600 MHz Low-E 3.2 mm MAS 1H–X–Y probe 750 MHz Low-E 4.0 mm MAS 1H–X probe

sample:  Pencil 3.2  (25 kHz) sample:  Pencil 3.2  (25 kHz) sample:  Pencil 4.0  (18 kHz)

Aligned Membrane Protein NMR

Double- and triple-resonance static Low-E probes with sample coils for both flat and bicelle sample preparations are available at 900, 720, 600, and 400 MHz, as indicated below. Observations of orientational constraints from PISEMA or similar non-spinning experiments are used for structure determination in membrane proteins. X and Y channels on the probes below can be re-configured to desired nuclei.

900 MHz Low-E static 1H–X probe 720 MHz Low-E static 1H–X probe 600 MHz Low-E static 1H–X–Y probe 600 MHz Low-E static 1H–X probe 600 MHz Low-E static 19F–1H probe 400 MHz Low-E static 1H–X probe

sample:  F4x6 flat and B5-2 bicelle sample:  F4x6 flat and B5-2 bicelle sample:  F4x6 flat and B5-2 bicelle sample:  F4x6 flat and B5-2 bicelle sample:  F4x6 flat sample:  F4x6 flat and B5-2 bicelle

Ultrafast MAS

The ultrafast 1.3 mm ¹H–X–Y triple-resonance MAS probe from Bruker is available on the 600 MHz wide bore magnets. This probe reaches speeds of 70 kHz and is particularly suited for the ¹H high-resolution NMR of solids.

600 MHz Bruker 1.3 mm 1H–X–Y fast MAS probe

sample:  Bruker 1.3  (70 kHz)

Quadrupolar and Low-γ NMR

MAS probes are available on the ultra narrow bore (31mm) 830MHz magnet for quadrupolar and insensitive low-_γ nuclei. Three rotor diameters (1.8, 2.75, 4 and 7mm) can be selected from for either maximum sensitivity or spinning speed. The 4mm MAS probe is optimized with a balanced rf circuit with strong rf for MQMAS and STMAS experiments. The probes are for room temperature due to the small bore size.

830 MHz 7.0 mm MAS probe for low-γ nuclei 830 MHz 4.0 mm MAS probe for low-γ nuclei 830 MHz 1.8 mm MAS probe for low-γ nuclei

sample:  Tallinn 7.0  (8 kHz) sample:  Bruker 4.0  (10 kHz) sample:  Tallinn 1.8  (40 kHz)

19F NMR

Two probes for fluorine NMR are available on the 600 MHz wide bore magnet:

600 MHz Bruker 4.0 mm 1H–19F–X MAS probe 600 MHz Low-E static 19F–1H probe

sample:  Bruker 4.0 sample:  F4x6 flat

NMR in Resistive Magnets

The 25 Tesla resistive and the 45 Tesla hybrid magnets allow to perform NMR experiments at ultra-high magnetic fields. Access time is rather limited and is scheduled through the DC Field Facility. These powered magnets have short term temporal stabilities of ~5 ppm. A more stable 36 T series-connected hybid (SCH) magnet will be dedicated to solid-state NMR experiments upon its completion in 2015. It will have field homogeneity and stability within 1 ppm. A Tecmag Discovery NMR console is available for NMR on the 45 T Hybrid and 25 T Keck magnets. A flux stabilization system, ferromagnetic and active shims are being optimized for the 25 T system.

1.065 GHz high-res 4 mm 1H–{13C, 2H} MAS probe 1.8 mm, 40 kHz fast MAS probe

sample:  Bruker 4.0 sample:  Tallinn 1.8  (40 kHz)

Low Temperature MAS NMR

The 3.2 mm ¹H/X broadband MAS probe with low variable-temperature range is available on the 900 MHz system. The temperature range of -138 to +127°C allows for studies of molecular dynamics and phase transitions.

900 MHz 3.2 mm MAS 1H–X low temp. probe

sample:  Pencil 3.2

Double Rotation

The double rotation (DOR) technique can directly obtain isotropic high-resolution spectra of half-integer quadrupolar nuclei. A double rotation probe is available to users of the 720 MHz NB magnet. Its 4 mm inner rotor spins inside the slower 9 mm outer rotor with 6 kHz and 1.5 kHz maximum speeds, respectively.

Stray Field Imaging (STRAFI)

A STRAFI probe is available at the 830 MHz (19.6 T) spectrometer. It operates outside of sweet spot at the field of 11.7 T corresponding to location of maximum 75 T/m stray field gradient produced by this magnet. The STRAFI probe can achieve spatial resolution of ~10 μm in layered samples such as battery cells.

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Address inquiries to Zhehong Gan (both 600s and the 830 MHz) or Riqiang Fu (900, 400, 300 MHz). Availability of 25 and 45 tesla systems is rather limited; please contact William Brey first.