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Research was conducted to examine the inner-sphere cluster formation by (Ru(NH3)5H2O)3+ or (Os(NH3)5H2O)3+ in combination with (M(CN)6)4- (M = Fe, Ru, or Os). The electrochemical behavior of the multinuclear centers in close proximity was also investigated. Results demonstrate that when acid is present to eliminate the adverse effect of internal proton transfer, the rate increase is only a factor of 1.5 or so while in the case of protonated anion about cation, the rate increase is a factor of 3.3. Findings provide insight into the stabilization of (M(CN)6)4- relative to (M(CN)6)3- by (M'(NH3)5)3+ and the stabilization by (M(CN)6)4- of (M'(NH3)5)3+ relative to (M'(NH3)5)2+.

Trans-(Os(en)2 (eta(super 2)-H(2)) H(2)O) (super 2+) in water has high affinity for Fe (CN)(6) (super 4-) and four other cyano complexes. Colorless trans-(Os-(en)(2) (eta (super 2)-H(2)) Fe(CN)(6))(super 2-) undergoes oxidation with FeCp(2) (super +) and other reagents to produce a deep blue color. Mixed valence species formation is responsible for this blue color. Cyclic voltagram and NMR are used to characterize these products which exhibit metal-to-metal charge-transfer absorption.

The complexes RuIIICp(CPD)(CH3CN)+ and RuIICp(CPD)2(super 2+), where CPD = 2,4-cyclopentadiene-1-one were prepared and used as precursors to nucleophilic attack reactions. These complexes react with nucleophiles such as nitriles, pyridine, halides, thiourea, 4, 4-bipyridine, isocyanides and thioethers to yield mononuclear products of the form, RuIIICp(CPD)(nucleophile). The 1H and 13C NMR spectra of the products showed similar patterns for all the RuCp(CPD)+ moieties. The structure of the PF6- crystals of the Ru complexes are also discussed.

The synthesis of osmahexatriene provides more insight into the chemistry of metal carbene complexes. Heating the triflate salt of the osmacyclopentatriene complex Os(en)2(C4Me4) (en = ethylenediamine) in tetrabutylamine yields, upon evaporation of t-BuNH2, a new complex in which the cyclic carbene ligand has isomerized into a conjugated hexatriene. Treatment with hydrochloric acid yields a crystallizable form of the complex. The reaction mechanism involves deprotonation of an alpha-methyl moiety in a 1,2-hydrogen shift that eventually protonates the Os-C single bond.