Varian 400 MHz
This instrument is mainly used in direct hands-on operation by trained students. The AutoX DB probe is used mainly for direct observation of heteronuclei, although it is capable of proton and fluorine-19 also. This machine is also used for VT studies, both above and below ambient.
- Console
- Varian DirectDrive NMR Systems, 2 Channel
- Magnet
- Varian / Magnex 9.4 Tesla (400 MHz)
Premium Shielded 54 mm Narrow Bore - Probes
- 5mm 1H-19F/15N-31P with z-gradient (AutoX DB probe)
- Sample Changer
- None
Available Nuclei
The following heteronuclear experiments are available for use on this machine. If you need another nucleus, with resonance frequency between 31P and 15N, just let me know.
| Nucleus | Spin (I) | Comments |
|---|---|---|
| 19F | 1/2 | Very sensitive to molecular environment. |
| 31P | 1/2 | |
| 7Li | 3/2 | More sensitive than 6Li but often had broader lines due to larger quadrupole moment. |
| 119Sn | 1/2 | Negative-γ, easy to observe. |
| 117Sn | 1/2 | Negative-γ, easy to observe, 119Sn is generally preferred. |
| 11B | 3/2 | Generally the preferred isotope. |
| 23Na | 3/2 | Easily observed, but little use for high resolution NMR in the solution state. |
| 13C | 1/2 | |
| 195Pt | 1/2 | |
| 207Pb | 1/2 | Usually quite straightforward. |
| 29Si | 1/2 | Negative-γ, long relaxation times often an issue. Broad signal usually seen at approximately -100ppm due to the NMR tube. |
| 77Se | 1/2 | Fairly easy to observe. |
| 199Hg | 1/2 | |
| 171Yb | 1/2 | Generally only observable in the +II oxidation state. |
| 6Li | 1 | Has very sharp lines due to low quadrupole moment. |
| 10B | 3 | Generally low sensitivity, 11B is generally preferred. |
| 15N | 3 | Negative-γ, generally low sensitivity and long relaxation times. Inverse detection is usually preferred. |