Pulse sequence building blocks

The inclusion of average Hamiltonian theory derived pulse sequence building blocks specifically designed for the measurement of RDCs is highly desirable. The homonuclear dipolar decoupling sequences used in ref. 190 lead to the less complex multiplet structures observed in isotropic samples with the chemical shift resolution reduced by a factor of 2-3, depending on the multiple pulse... 

This is frosting on the cake, and I only bring it up to show the beautiful things you can accomplish with pulse sequence building blocks. The only protons we are interested in are those bonded to a 13 C, because these are the only ones that can transfer magnetization to 13C. If we consider the other nuclei that have homonuclear coupling to the (13C-bound)... 

The -frmction excitation is not only the simplest case to consider it is the frmdamental building block, m the sense thatv the more complicated pulse sequences can be interpreted as superpositions of 5-frmctions, giving rise to superpositions of M avepackets which can in principle interfere. 

Hyphenated heteronuclear shift correlation methods Many of the experiments described thus far can be used as building blocks to create more sophisticated pulse sequences. The earliest variants of hyphenated NMR experiments, such as HC-RELAY, were heteronuclear detected [56]. More recent hyphenated heteronuclear shift correlation methods are based on proton detection and include... 

The INEPT (Insensitive Nuclei Enhanced by Polarization Transfer) experiment [6, 7] was the first broadband pulsed experiment for polarization transfer between heteronuclei, and has been extensively used for sensitivity enhancement and for spectral editing. For spectral editing purposes in carbon-13 NMR, more recent experiments such as DEPT, SEMUT [8] and their various enhancements [9] are usually preferable, but because of its brevity and simplicity INEPT remains the method of choice for many applications in sensitivity enhancement, and as a building block in complex pulse sequences with multiple polarization transfer steps. The potential utility of INEPT in inverse mode experiments, in which polarization is transferred from a low magnetogyric ratio nucleus to protons, was recognized quite early [10]. The principal advantage of polarization transfer over methods such as heteronuclear spin echo difference spectroscopy is the scope it offers for presaturation of the unwanted proton signals, which allows clean spec-... 

Various NMR pulse sequences contain certain building blocks like BIRD, INEPT, refocusing delay etc., that perform some specific functions. A building block that serves... 

CH2, or CH3) is achieved with a ubiquitous building block of NMR pulse sequences the spin echo. 

Now that we know most of the basic building blocks of NMR pulse sequences, we should be able to use the coherence flow diagram (Fig. 11.9) to design an HSQC pulse sequence. It needs to accomplish the following steps ... 

The COSY pulse sequence can be modified to provide a 2D spectrum that is decoupled in the a)t dimension while retaining coupling in crowded spectra, as the chemical shifts are clearly revealed. Although this experiment is not widely used as such, it serves as a prototype for a building block in other more complex 2D and 3D experiments. 

The CP step is an essential building block for pulse sequences in solid-state NMR. The easiest ID experiments that are routinely used for characterization of organic, organometallic and hybrid solids are total suppression of spinning sidebands (TOSS), nonquatemary suppression, and so on. 

Homonuclear or heteronuclear Hartmann-Hahn mixing periods are versatile experimental building blocks that form the basis of a large number of combination experiments (see Section XIII). In practice, the actual multiple-pulse sequence that creates Hartmann-Hahn mixing conditions can usually be treated as a black box with characteristic properties. In this section, design principles and practical approaches for the development of Hartmann-Hahn mixing sequences are discussed. 

Since the first description of the Hartmann-Hahn transfer in liquids, spectroscopists have been fascinated by this technique. Many theoretical and practical aspects have been thoroughly investigated by several groups. With the development of robust multiple-pulse sequences, homonuclear and heteronuclear Hartmann-Hahn transfer has become one of the most useful experimental building blocks in high-resolution NMR. 

There have been many enhancements of the original TROSY pulse sequence,74 and even more applications that use TROSY as a building block in multi-... 

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