| Summary: | The isomerization of 1-penten-3-ol into 3-pentanone
catalyzed by [RuCp(H2O-κO)(PTA)2](CF3SO3) (1CF3SO3) (PTA
= 1,3,5-triaza-7-phosphaadamantane) was studied and two watersoluble
ruthenium catalyst reaction intermediates were characterized.
The main intermediate, the complex [RuCp(exo-η2-1-penten-3-
ol)(PTA)2](CF3SO3)·2H2O (exo-2CF3SO3·2H2O), was isolated
and characterized by NMR in solution and by single-crystal X-ray
diffraction in the solid state, constituting the first example of a fully
characterized complex containing a coordinated η2-allylic alcohol and
the first crystal structure for a water-soluble metal complex
containing a η2-allyl ligand. NMR and Eyring analysis show the
crucial involvement of water molecules both in the transformation of
allylic alcohol into a ketone as well as in the concomitant
isomerization of the exo-coordinated substrate into the endo-conformer. DFT structure and bonding analyses are used to assess
the relative stabilities of the isomers and how the metal drives the electronic distribution on the substrate.
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