DEPTNOE

DEPTNOE is an in-house written macro that carries DEPT and NOE-enhanced C13 detection (all C13 signals are detected) in one experiment. Refer to the DEPT instruction for details on DEPT. The macro is meant to be used for automated data collection, processing and printing processes (remember to enter au, not go or ga to start experiment). Manual parameter control is possible, as instructed below.

In the {H1}C13 NOE experiment, broadband H1 decoupling is applied during the recycle delay in addition to that during the acquisition period to enhance the H1-attached C13 signals.

Note:

• You are strongly recommended to tune both H1 and C13 channels. DEPT requires accurate 90 degree 1H and to a lesser degree 13C 90 degree pulse width to give a clean editing results.

C13 referencing

• For accurate C13 referencing, add TMS or DSS (in aqueous solution) to your deuterated solvent. Use 1H signal from TMS or DSS for 0.0ppm reference and C13 is indirectly referenced according to IUPAC standard .
• For rough referencing with the lock signal, simply type setref.

Procedure (on NMR500 with SWP probe)

deptnoe macro

• This is a macro written a while ago for the same experiment. After deptnoe is entered, the experiment starts immediately using default parameters. Type stop to abort the experiment if signal is satisfactory. Follow the printing instruction below.
• Please use the new procedure below and tune the H1 (use channel 2) and C13 X-channel (use channel 1) before starting the experiment. For tuning purpose, you can simply type tn='C13' dn='H1' su under any experiment before tuning.

Step 1: Tune, lock and shim

• Turn ON temperature regulation (default on nmr500 at 22C)
• Turn OFF spinning
• Under exp2 (type jexp2 to join exp2):
• Type initshims to reset shim values
• Type setexp('deptnoe') to load parameters.
• Change solvent, lock and shim Z1/Z2 then X1/Y1 and then readjust Z1/Z2. Keep lock level at ~80%.
• Tune both 1H channel and X-channel for 13C. This is critical for clean editing results.
• Type su in exp2 before tuning
• Tune 1H channel (channel 2)
• Tune X-channel (channel 1) to C13. No tuning stick is needed.
• Check 1/4-wavelength cable on broadband preamp. Make sure it is for C13.

Step 2: Start experiment

• Type au to start experiment with default parameters.
• Experiment starts in interleaved mode with bs=16. In the this mode, each of the five elements of the array is run bs scans and then the cycle starts from the 1st element again for another bs scans. Each cycle takes ~ 2.2 mins.
• Stop the experiments by typing stop whenever you feel the sensitivity is sufficient. DO NOT use aa or click the Abort Acquisition button. Doing so may terminate the data acquisition in the middle of the array, making the intensity uneven among array elements.

Step 4: Processing and printing

• Check during data collection:
• Type pldeptnoe2 to process data and display spectra on screen. Note only DEPT (the 1st four elements) is processed and displayed. To display the all-C13 spectrum, simply type wft(5) f full aph.
• Type pldeptnoe to process and print spectra to printer. Processing and printing starts after the current array cycle finishes. Both processed DEPT and all-C13 spectrum are printed.
• After data collection:
• Type pldeptnoe2 page to print to printer. Both processed DEPT and all-C13 spectra are printed.
• Type pldeptnoe2('deptnoe.pdf') or pldeptnoe2('deptnoe.jpg') to print to a .pdf or .jpg file under your current folder. Type pwd to see what is the current folder. See this page, for more on printing.
• Referencing:
• Type setref to reference the C13 spectrum via the lock signal
• For accurate referencing with TMS, see optional step below.

Optional: For accurate C13 referencing with TMS H1 signal

• Under a separate experiment (exp1), collect a quick H1 spectrum. Reference TMS peak to 0.0ppm
• Join deptnoe experiment (exp2), type mref(1,2).

Default parameters

• ss=8 nt=16*1024 bs=16
• d1=1 at=1 gain=34 lb=1
• tpwr=56 pw=12.5 (for 13C)
• pplvl=57 pp=9.0 (for 1H, in cdcl3)
• mult=0.5, 1, 1, 1.5, 0
• 13C center tof: ~ 101ppm, sw ~ 280ppm covering -40ppm to 241ppm.
• 1H center dof: ~ 4.2ppm with 1H decoupling during 13C acquisition

Manual adjustment of parameters

Although this script is meant to used with default parameters, you can still change the parameters before entering au to start experiment. Check or change the following parameters as needed:

• pp (for H1)
• If some imperfection is to be tolerated in the final spectra, use the default pulse widths. Otherwise, for best quality or if you observe excessive poor editing results, calibrate 1H 90 degree pulse width with a precision of 0.5 usec at tpwr=57. The default setting assumes cdcl3 as solvent at 22C, but should also apply to solvents with similar dielectric properties.
• Change pp at tpwr=57 to calibrated value if available
• sw
• Default center is 101ppm and spectral width is 280ppm, good for most samples.
• nt
• Default nt=16*1024. It is large enough for most samples.

Example

Sample: Strychnine at ~ 25mg/mL (~ 100mM) in cdcl3 Data collected October 2010
Spectra further processed with pldeptnoe2 command. From top to bottom: 1: CH3 2: CH2 3: CH 4: All (C+CH+CH2+CH3)

H. Zhou updated Dec 2010