In this chapter we provide several basic 1D pulse sequences where more than one rf.

pulse is applied. These pulses have to be calibrated for both the transmitter and decou- pler channels. Due to error propagation these sequences are sensitive to miscalibration of the r.f. pulses and you will only succeed if these are correct.

Since a knowledge of both spin-lattice and spin-spin relaxation times is very im- portant in multipulse NMR spectroscopy, this chapter begins with the two basic ex- periments for 7, and 7, measurements. A large part (Exps. 6.3-6.12) is then devoted to techniques for multiplicity determination with and without polarization transfer.

There have been numerous discussions in the literature on the relative performance of these techniques. We give the basic descriptions of the most often used methods, SEFT, APT, INEPT, DEPT, as well as the recent DEPTQ and PENDANT techniques, and leave it to the reader to decide which variety best serves his or her own particular After an introduction to 1D-INADEQUATE (Exp. 6.13), four purely educational sequences are described: the use of BIRD, TANGO, the double quantum filter, and purging with a spin-lock. Together with the basic INEPT and reverse INEPT se- quences, these six experiments are shown for the simple case of the CHCI,; molecule.

However, we feel that a lot can be learned about modern multipulse NMR techniques from performing these experiments as shown.

Two methods for suppressing the huge solvent signal of water conclude the chapter.

It should also be mentioned that other water suppression techniques using pulsed field gradients are described in Experiments 11.16–-11.18.

Literature

[1] C.1. Turner, Prog. NMR Spectrosc. 1984, 16, 311-370.

[2] T. D. W. Claridge, High-Resolution NMR Techniques in Organic Chemistry, Per- gamon, Oxford, 1999, Chapter 4.