Dihydridoruthenium complexes

In this section, we will review the nature and chemical reactivities of several kinds of ruthenium complexes under the following headings ruthenium carbonyl complexes, dichlororuthenium complexes, chlorohydrido complexes, dihydridoruthenium complexes, ruthenium complexes with chiral ligands, ruthenium complexes with cyclopentadienyl ligands, and ruthenium arene/diene complexes. 

Several cw-dihydridoruthenium(II) complexes of general formula [R11H2L4] have been claimed to follow the dihydride route merely because of their stoichiometry. Since these complexes are coordinatively saturated, they must lose the neutral hgand trans to a hydrido ligand to allow alkene coordination to take place. This would then allow the formation of an alkyl complex since the alkene would be coordinated cis to the second hydride. Since both alkene isomerization and H/D exchange can be observed in the system, the alkyl complex must have a long lifetime. ... 

Similarly, dihydridoruthenium(II) complex RuH2(PBu3)4 also catalyzes codimerization betv een terminal alkynes and dienes giving enynes [13]. Regioselective codimerization of internal alkynes with alkenes having an electron-withdrawing group also proceeds by Ru(l,5-COD)(l,3,5-COT) (Scheme 14.4) [14]. In this reaction, a mthenacycle complex is considered to be involved as an intermediate. 

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