NMR magnetization transfer

Magnetization transfer NMR experiments on the two isomers (24) and (25) of [Fe(T -C8H8)(CO)2(CNPr )] have been used to demonstrate a specific transfer of the iron about the cyclooctatetraene ring in a way... 

Magnetization transfer via proton-driven-spin-diffusion (PDSD) in MAS NMR is not by any means a new experiment. It was introduced in the early 1980s by Maciel and coworkers [136] and later used, described, and analyzed by numerous groups in relation to, e.g., biological solid-state NMR. In its original form, the experiment consists of a couple of oppositely phase n/2 pulses bringing the low-y... 

In the isoelectronic series (butadiene)M( j8 — CgHg) (M = Ti, Zr, Hf), the Hf complex exhibits an NMR spectrum at > 30 °C consistent with an envelope flip (AG = 17.6 kcalmol-1). The same process can be detected for the Zr complex at > 40 °C only via magnetization transfer experiments (AG > 20 kcalmol-1). The Ti complex exhibits a static structure by NMR spectroscopy16. 

Pulse sequence for MAS NMR. A) CFMAS. B) CPNAS with TOSS. T is magnetization transfer A, acquisition X,Y, -X are pulse phases and represents a delay. 

---