4. Acquisition

Time requirement: 10 min Sample: Commercial 1.4 M n-butyllithium in n-hexane; add 10% dry [D,]THF for locking purposes. Seal the sample with Parafilm®. The measurement can be done at room temperature.

Record normal ¹H and ⁷Li NMR spectra, change to the 2D mode of the spectrometer, and load the gs-HOESY pulse program. You have to set:

td2: 2048 data points in F2 td1: 32 data points in F;

sw2: 5 ppm swl: 2.5 ppm offset of ¹H frequency: middle of ' H NMR spectrum offset of ⁷Li frequency: middle of Li NMR spectrum p1, p2: 90° 7Li decoupler pulse p3: 180° ⁷Li decoupler pulse p4: 180° ¹H transmitter pulse p5: 90° ¹H transmitter pulse dl:2s d2: 1 ms, set equal to gradient duration d3: 400 ms mixing time g1, g2, g3: sinusoidal-shaped field gradients of 1 ms duration and ca. 0.2 T/m strength for the largest gradient, with gradient loop counters, ring-down delays (100 pis), lock blanking and gradient coil blanking switches accord- ing to actual instrumentation used. Gradient strength ratio: 36 : 50 : 14.

initial value for ¢; evolution: 3 μs increment for ¢; evolution = 1/[2-sw1] decoupler attenuation and 90° pulse for CPD

5. Processing

Apply zero-filling in F to 64 real data points. Use exponential windows with lb = 5 Hz in F, and a n/2-shifted squared sinusoidal window in F;. Apply complex Fourier transformation corresponding to the N-type signal selection using the quadrature-off mode in F\. Phase correction is not necessary since the data are displayed in magni-