Samples are also substantially larger than in Bruker W-Band, so that spectra are often better than those obtained on the Bruker machine if enough sample is available. Thin Teflon vessels with an outer diameter of up to 9 mm and a depth of up ca. 10 mm are used as sample containers. Standard X-Band 3 mm and 4 mm quartz tubes can also be used for samples requiring sealing. Gelatin capsules up to the size ‘00’ (8 mm diameter) as well as polyethylene vials were also successfully employed. The sample temperature can be controlled over the range of 3K to 309K.
The samples are most often powders or frozen solutions in organic solvents or in water. Single crystals can be measured, but no crystal rotator is available.
The instrument does not employ resonance cavity. The superconducting magnet has been factory-calibrated, but for accurate measurements usage of g standards is recommended (for example DPPH or phosphorus doped into silicon).
Transition metal complexes, some compounds of the f-electron metals (gadolinium) as well as organic radicals have been studied on this spectrometer. The sensitivity is sufficient for studies on some enzymes (the manganese-containing oxalate decarboxylase, for example).
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Details
- Frequency: 24 – 660 GHz
- Field: Up to 17 tesla
- Temperature: 3 K – 309 K
- Crystal Rotation: No
- Pressure: Ambient
- Sensitivity: Absolute: 1013 spin/mT, concentration: 5·1013 spin/(cm3·mT)
- Sample Size: 5-300 mg (powder), 0.2-1 mL (solution)
- Optical Excitation: Yes
- The microwave source of this instrument can be also used with the resistive magnets of the DC facility
- The BWO microwave source can be used with this instrument
- Air-sensitive or reactive sample
- Frozen solutions, including aqueous
- Powders & polycrystals
- Single crystal
- Thin films
Images & Sample Data
Click on images for details.
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The transmission spectrometer.
The transmission spectrometer.
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Sample holders.
Sample holders.
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Sample holder.
Sample holder.
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The system's superconducting magnet reaches 17 tesla.
The system's superconducting magnet reaches 17 tesla.
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The microwave detector for the transmission spectrometer.
The microwave detector for the transmission spectrometer.
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The microwave source for the transmission spectrometer
The microwave source for the transmission spectrometer
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High-Field EPR of Copper Acetate.
High-Field EPR of Copper Acetate.
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High-Field Spectra of a Cr3+-Cr3+ System.
High-Field Spectra of a Cr3+-Cr3+ System.
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DPPH in Toluene: X-Band.
DPPH in Toluene: X-Band.
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DPPH in Toluene: HF EPR.
DPPH in Toluene: HF EPR.
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Trinuclear Cr2+ complex with an S=2 ground state.
Trinuclear Cr2+ complex with an S=2 ground state.
https://nationalmaglab.org/user-facilities/emr/instruments-emr/transmission#sigProId202af45cd3
Related Publications
Stoll, S., et al, Hydrogen bonding of tryptophan radicals revealed by EPR at 700 GHz, J. Am. Chem. Soc., 133 (2011) Read online
Tran, B.L., et al, Reactivity studies of a masked three-coordinate vanadium(II) complex, Angew. Chem. Int. Ed., 49 (2010) Read online
Krzystek, J., et al, Cobalt(II) “scorpionate” complexes as models for cobalt-substituted zinc enzymes: Electronic structure investigation by high-frequency and -field Electron Paramagnetic Resonance spectroscopy, J. Am. Chem. Soc., 132 (2010) Read online
Ozarowski, A., et al, High-Field EPR and Magnetic Susceptibility Studies on Binuclear and Tetranuclear Copper Trifluoroacetate Complexes. X-ray Structure Determination of Three Tetranuclear Quinoline Adducts of Copper(II) Trifluoroacetate, J. Am. Chem. Soc., 131 (2009) Read online
Ozarowski, A., et al, High-Frequency and -Field EPR of a Pseudo-octahedral Complex of High-Spin Fe(II): Bis(2,2'-bi-2-thiazoline)bis(isothiocyanato)iron(II), J. Am. Chem. Soc., 126 (2004) Read online