Parahydrogen induced polarization

Duckett381 reported on the use of parahydrogen-induced polarization (PHIP) to delineate the pathways involved in the catalytic hydrogenation of alkenes and alkynes by [Ru3(CO)12 x(PPh3)x] (x = 1 or 2) and showed that the mechanism is highly dependent on the solvent. Bassett and... 

Parahydrogen-Induced Polarization Applications to Detect Intermediates of Catalytic Hydrogenations... 

The nmr measurement of dipolar relaxation (Tx) can give data that can be correlated with M—H bond distances, however, and has been useful in distinguishing between MH and M(H2) species as discussed later. Enhancement of nmr signals by parahydrogen induced polarization can allow detection of isomers in low concentrations.58... 

The mechanism of H2 addition to Cp 2Ta(=CH2)H has been studied using parahydrogen-induced polarization (PHIP), C labeling, and comparison to the related complex Cp 2Ta(=CH2)Me. The reaction of />ara-enriched H2 with labeled Cp 2Ta(= CH2)H leads to polarized resonances for both Cp 2TaH3 and Cp 2Ta(CH3)H2, where the polarized resonances correspond to the two hydride hgands. The results thus support a pathway of H2 addition to a Ta(lll) intermediate Cp 2TaCH3, rather than addition directly across the Ta=C bond. ... 

Lanthanide chelates have been used as aids in studying the products of hydrogenation reactions monitored through parahydrogen-induced polarization (PHIP). Carrying out... 

ALTADENA (Adiabatic Longitudinal Transport after Dissociation Engenders Net Alignment) [56]. All variants are nowadays known under the more generally acronym of PHIP (Parahydrogen Induced Polarization) [52]. The basic theory ofthe PHIP effect in an AX-spin system was given in the review paper of Bowers and Weitekamp [56]. 

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