| Abstract
| - Complexes of the type[Ru(η5-C5H5)(η4-C5H4O)(L)]CF3SO3(L = CH3CN (1a), benzonitrile(1b), pyridine (2),thiourea (3)) react with tertiary phosphines to give either1,1‘- or 1,2-disubstituted ruthenocenes depending on thebasicity of the entering phosphine and the nature of L. For1a and 1b, only phosphines with apKa value above5 substitute on the C5H5 ring while otherssubstitute on the C5H4O ring. Forcompounds 2 and 3, the two ringsare deactivated such that only the most basic phosphines react, andthey attack only the C5H4O ring. Insomecases of the reactions of 2 and 3, anintermediate is observed in which the monodentate ligand has migratedtothe C5H5 ring while the entering nucleophilecoordinates to the metal center. The mechanism by whichphosphinesattack a coordinated C5H4O ring has beenestablished, and detailed kinetic parameters have been obtained.Forthe reaction of 1a with PPh3,PPh2Me, and P(p-PhOMe)3 inacetone, the kinetics give a rate law indicating thereversible formation of an intermediate which goes irreversibly to the1,2-disubstituted ruthenocene product. Allthree rate constants and their thermal activation parameters have beenobtained for each of these reactions. Forthe P(p-PhOMe)3 reaction, the volume of activation for eachstep has also been determined. The reaction of2and 3 with PBun3, PCy3,PPhMe2, and PMe3 in CD3CN givea long-lived intermediate which also goes to the1,2-disubstituted ruthenocene product. For the intermediatesformed from 3, the kinetics of this last stephavebeen studied to determine the rate constants and their thermalactivation parameters. In the case ofPBun3, theintermediate formed from 3 has been isolated and an X-raystructure determined, establishing that phosphineattack has occurred at the C5H4Oring.
- Complexes of the type[Ru(η5-C5H5)(η4-C5H4O)(L)]+(L = acetonitrile (1a), benzonitrile (1b),pyridine (2), or thiourea (3)) react withtertiary phosphines to give either 1,1‘- or 1,2-disubstitutedruthenocenes depending on the basicity of the entering phosphine andthe nature of L. For 1a and 1b, onlyphosphines with a pKa value above 5 substituteon the C5H5 ring. The kinetics andmechanism of the phosphine attack on a coordinatedC5H4O ring have beenestablished.
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