4. Acquisition

Time requirement: 15h Sample: 80% 1-hexanol in [De]acetone.

Tune the probe-head to the actual sample, record a normal ¹³C NMR Spectrum and optimize the spectral width. Determine the ¹³C observe pulse-length for this sample. For this experiment the instrument must be set so as to obtain optimum performance. Change to the 2D mode of the spectrometer and load the 2D-INADEQUATE pulse program. You have to set:

td2: 2 k data points in F, td1: 128 data points in F, sw2: 60 ppm sw1: 120 ppm (double-quantum frequency) o1: middle of "*C NMR spectrum p1, p3, p4: 90° ¹³C transmitter pulse p2: 180° ¹³C transmitter pulse dl:3s d2: 1/[44(C,C)] = 7.6 ms, calculated from 'J (C,C) = 33 Hz decoupler attenuation and 90° pulse for CPD initial value for ¢; evolution: 3 μs increment for ¢, evolution = 1/swl ds: 4

5. Processing

Apply zero-filling in F; to 1k real data points to obtain a matrix of 1024x512 real data points. Use 7/2-shifted sinusoidal windows in both dimensions. Apply complex Fourier transformation corresponding to the N-type signal selection using the quadratureoff mode in F\. Phase correction is not. necessary, since the data are processed in the

6. Result

The figure shows an expansion of the 2D-INADEQUATE spectrum obtained on an DRX-600 spectrometer. Some breakthrough of axial signals at d) = 78 can be observed. Each pair of connected ¹³C nuclei forms an AX or AB spin system, which is found in the same row of the data matrix; the pairs of doublets are symmetrical with respect to the diagonal (dotted line), and spin coupling constants can be obtained from such a row. If one carbon is connected to more than one other carbon, the corresponding doublets are found at the same chemical shift in F, but at another double-quantum frequency in F;. Thus the molecular carbon skeleton can be obtained by a criss-cross progression through the 2D spectrum.