TEDOR transferred echo double

The REDOR experiment has formed the basis for a large number of ideal pulse type recoupling experiments, and later finite pulse variants, for heteronuclear dipolar recoupling. These include experiments such as frequency selective REDOR (FS-REDOR) [80], TEDOR (Transferred Echo DOuble Resonance) [25], and 3D variants of TEDOR [81, 82], which have found important applications, e.g., for measurement of intemuclear 13C-15N distances in biological solids. We should also mention that rotor-encoded variants of TEDOR, such as REPT, HDOR [83], and REREDOR [84], have been proposed for 1H13C dipolar recoupling under high-speed MAS conditions. 

At the qualitative level, NMR studies devoted to this issue exploit heteronuclear dipolar recoupling to correlate resolved MAS NMR signals of the nuclear species associated with different network formers. This information comes from the dephasing of the observe nuclei in REDOR, TRAPDOR, or REAPDOR experiments, or from one- or two-dimensional correlation spectroscopy involving coherence transfer via TEDOR (transferred echo double resonance) or... 

The main problem is that the SEDOR experiment is carried out imder static conditions, i.e., without magic angle spinning. Therefore, SEDOR measurements only yield average values for the internuclear distance if a sample contains two or more different types of 7-S-spin pairs with different internuclear distances, r/j. Typical double resonance experiments for the measurement of internuclear distances under magic angle spinning conditions are the REDOR (rotational-echo double resonance [50]) and the TEDOR (transferred-echo double resonance [51]) techniques. 

To be exhaustive about ID double resonance NMR experiments, we have to mention the TEDOR (transferred echo double resonance) experiment, which involves transferring magnetization between two heteronuclear spins [45]. Nevertheless, this experiment has been applied only once to Al-based fluoride, on AIPO4-CJ2, a microporous... 

Another useful technique which is closely related to fsREDOR is the band-selective transferred echo double resonance (BASE TEDOR) [102]. As shown in Fig. 6, the... 

Many multiple resonance methods such as cross-polarisation (CP), Rotational Echo Double Resonance (REDOR), and Transferred Echo Double Resonance (TEDOR) are available. Their application can be differentiated between systems involving exclusively spin- /2 nuclei and those containing quadrupolar nuclei. The presence of quadrupolar nuclei may prohibit straightforward application of these experiments and can affect the interpretation of the results. There are, however, benefits arising from the presence of quadrupolar nuclei, as illustrated by the Transfer of Populations by Double Resonance (TRAPDOR) experiment which will only work for quadrupolar nuclei. 

From the success of the cross-polarization experiments, one may predict success for a variety of related experiments that depend on the dipolar interaction (such as those of Veeman [951, where spin echoes are observed under magic-angle spinning and double resonance conditions). Further experiments that allow determination of internuclear distances should also be possible, including rotational-echo double-resonance (REDOR) NMR [96], and transferred-echo double-resonance (TEDOR) NMR [97], the latter being related to INEPT experiments in liquids. 

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