Cationic metal carbonyls phosphine derivatives

The metal center in (i9 -C5H5)M(L)(CO)(allyl) can be considered pseudotetrahedral and characterized by the (R) and (5) nomenclature. Neutral chiral complexes of this type have been prepared previously, e.g., phosphine carbonyl derivatives (21, 75) and nitrosyl halide derivatives prepared by carbonyl displacement from nitrosyl cations by iodide (57, 60). Each of the diastereomers produced by the addition of a prochiral allyl moiety to the chiral metal center exhibit endo-exo isomerism. The endo-exo equilibration depends on charge and the neutral nitrosyl iodides rearrange rapidly compared to the cationic nitrosyls. 

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