Deuterium Decoupled Proton Spectra on AMX-400

Deuterium decoupled spectra must be run un-locked, it is not possible to lock an deuterium and decouple it at the same time.
The AM-500 drifts about 1 Hz/hr (deuterium), so you probably want to use one of the 400 MHz spectrometers.

We have tested the decoupling on the VBAMX on 5/12/95.

Remember to change all the cables and filters back after the experiment, please.
Please Fill In the LOG book now, stating that you changed cables for 2H NMR!
For deuterium decoupling, we can use the D-Lock coil while observing protons. Observing other nuclei is possible, but requires some custom rf filters.

  • First, run a proton and a deuterium spectrum.
  • Write down SFO1 for the Proton Spectrum.
  • Determine the frequency in the middle of the deuterium spectrum. To do this, set the X-axis units to Hz. Enter the Calibrate routine. The cursor will now display the absolute frequency in MHz. Note the frequency at the center.
  • Then, with the system configured for deuterium observe, use 'edsp' to set up 1H Observe, 2H Decouple. Type SFO1, enter the previously noted Proton SFO1.
  • Type SFO2, and enter the previously noted Deuterium center frequency.
  • Select the zgdclo pulse program. The decoupling parameters are dl0 for the decoupler power, P31 for the 90 deg CPD pulse width and cpdprg for the CPD sequence (normally waltz16).
    • We have run a spectrum with dl0 set to 20 and P31 set to 2 milliseconds.

    The sample, synthesized by Tom Petersen (Prof. R.G. Bergman's group), is
    Cp*(PMe3) Ir (CHD-CHD tBU)(Cl).

    The parameters are probably not completely optimized, but the spectrum showed us what we needed to know.
    Depending on the range to be decoupled, and the coupling constants, better optimization might be required.

    Questions, comments to: Rudi Nunlist rnunlist@bloch.cchem.berkeley.edu

    Last Update: 5/12//95. RN