STRUCTURE, SYNTHESIS, AND CHEMISTRY OF (PME3)4RU(ETA-2-BENZYNE) - REACTIONS WITH ARENES, ALKENES, AND HETEROATOM-CONTAINING ORGANIC-COMPOUNDS - SYNTHESIS AND STRUCTURE OF A MONOMERIC HYDROXIDE COMPLEX

Thermolysis of (PMe3)4Ru(Ph)(Me) or (PMe3)4Ru(Ph)2 leads to the ruthenium benzyne complex (PMe3)4Ru(eta-2-C6H4) (1) by a mechanism that involves initial reversible dissociation of phosphine. In many ways, its chemistry is analogous to that of early rather than late organo-transition-metal complexes. Thus, compound 1 undergoes apparent sigma-bond metathesis reactions with the C-H bonds of benzene or toluene solvent (the reverse of the formation of 1), the N-H bond in aniline, and O-H bonds of p-cresol, 2-propanol, and water. The monomeric hydroxide complex resulting from addition of water has been structurally characterized. Compound 1 also undergoes insertion reactions with a variety of unsaturated organic molecules, including ethylene, di-p-tolylacetylene, benzaldehyde, and benzonitrile. Qualitative mechanistic studies on the O-H addition of p-cresol and the insertion of benzaldehyde and benzonitrile are reported.