| Abstract
| - The preparation, immobilization, and structure of “second-generation” ruthenium benzylidene metathesis catalysts bearing hydroxyalkyl chains on their N-heterocyclic carbene ligands are described. Compounds of this type show a previously unknown bias to rearrange their ligand sphere such that the neutral ligands are cis-disposed to one another.
- The preparation, immobilization, and structure of “second-generation” ruthenium benzylidene metathesis catalysts bearing hydroxyalkyl chains on their N-heterocyclic carbeneligands are described. Complexes of this type are prone to rearrange their ligand spheresuch that the neutral ligands get cis- rather than trans-disposed. Moreover, treatment ofcomplex 7d with pyridine results in an unprecedented ionization by loss of one of its chlorideligands. The resulting cationic species 13, though devoid of catalytic activity, is the firstmember of a new type of ruthenium carbene complexes characterized by an octahedralcoordination geometry and a donor/acceptor interaction between the metal center and thetethered hydroxyl group. The trans-configured hydroxyalkyl-functionalized complexes 8aand 8b, the cis-configured compound 10, and the ion pair 13 have been structurallycharacterized by X-ray crystallography.
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