Time requirement: 6 h Sample: 10% triphenylphosphine in CDCl₃ This experiment requires a three-channel spectrometer and a probe-head that is tunable to ¹H, ¹³C, and *'P. Use appropriate r.f. pass and stop filters in all three channels. Record normal 1D ¹H, ¹³C and *'P NMR spectra, optimize the spectral widths (¹H, ¹³C) for the aromatic region only, and note the offsets. Switch to the 3D mode of the spectrometer software and load the H,C,P correlation pulse program. You have to set:

td3: 256 data points in F; (¹H) td2: 16 data points in F, C 'p) td: 64 data points in F; (¹³C) sw3: 0.6 ppm sw2: 0.5 ppm swl: 12 ppm o1: middle of selected ¹H NMR region [7.5 ppm] o2: middle of selected ¹³C NMR region [133 ppm] 03: middle of selected *'P NMR region [–6 ppm] p1, p3, p5, p7, p8: 90° ¹H transmitter pulse p2, p4, p6, p9: 180° ¹H transmitter pulse pil, p13: 90° ¹³C decoupler pulse p10, p12, pi4: 180° ¹³C decoupler pulse 3C decoupler attenuation and 90° pulse for GARP p16, p17: 90° *'P pulse in third channel of the spectrometer p15: 180° *'P pulse in third channel of the spectrometer dl:2s d2: 1/[4(C,H)] = 1.56 ms, calculated from 'J(C,H) = 160 Hz d3: 1/[2.(C,P)] = 38 ms, calculated from "J(C,P) = 13 Hz (average) initial values for ¢; and f, evolution: 3 μs increment for ¢, evolution: 1/[4-sw1]; increment for #, evolution: 1/[4-sw2] pre-acquisition delay: as small as possible

5. Processing

Apply zero-filling to 32 real data points in F, and to 128 real data points in F) to ob- tain a matrix of 12832128 real points. This will result in 1 MB of processed data.

Use an exponential window with lb = 3 Hz line-broadening in F; and 7/2-shifted squared sinusoidal windows in the other two dimensions. Apply the correct acquisition order parameter (3–1–2) before FT in all three dimensions. Phase correction is best performed after the FT of each dimension. Further details are very dependent on the particular software you use to process such a 3D data file.