Osmium hydride anion

Reduction by hydride transfer (H" = H + 2e ) occurs when the osmium cluster [Os3( -H)2(CO)io] is reacted with a whole variety of organoazides the hydride anion is transferred to the terminal nitrogen atom N3 and a monoanionic organoazide fragment is... 

The osmium hydrido-catbonyl H2Os3(CO)]0 has featured in an interesting stucty by Aime et al where its reactions wito sitn(de ligands (CO, NH3 and H2S) were examined. Osmiiim carbotiyl-hydride anions (eg. [H30s4(C0) 2r) 1> l>cen (uepared on silica firom [Os(CO)3Cl2]2 in toe presence of K2CO3 and toe reactions of... 

A ruthenium porphyrin hydride complex was lirst prepared by protonation of the dianion, [Ru(TTP) in THF using benzoic acid or water as the proton source. The diamagnetic complex, formulated as the anionic Ru(If) hydride Ru(TTP)(H )(THF)l , showed by H NMR spectroscopy that the two faces of the porphyrin were not equivalent, and the hydride resonance appeared dramatically shifted upheld to —57.04 ppm. The hydride ligand in the osmium analogue resonates at —66.06 ppm. Reaction of [Ru(TTP)(H)(THF)j with excess benzoic-acid led to loss of the hydride ligand and formation of Ru(TTP)(THF)2. 

The formation of these compounds has been rationalized according to Scheme 6. The reaction of Os (E )-CH=C 11 Ph C1 (C())( P Pr3)2 with n-BuLi involves replacement of the chloride anion by a butyl group to afford the intermediate Os (/i> CH=CHPh ( -Bu)(CO)(P Pr3)2, which by subsequent hydrogen (3 elimination gives OsH ( >CI I=CHPh (CO)( P Pr3)2. The intramolecular reductive elimination of styrene from this compound followed by the C—H activation of the o-aryl proton leads to the hydride-aryl species via the styrene-osmium(O) intermediate Os r 2-CH2=CHPh (CO)(P Pr3)2. In spite of the fact that the hydride-aryl complex is the only species detected in solution, the formation of OsH ( )-CH=CHPh L(CO)(P Pr3)2 and 0s ( )-CH=CHPh (K2-02CH)(C0)(P,Pr3)2 suggests that in solution the hydride-aryl complex is in equilibrium with undetectable concentrations of OsH ( )-CH=CHPh (CO)(P,Pr3)2. This implies that the olehn-osmium(O) intermediate is easily accessible and can give rise to activation reactions at both the olefinic and the ortho phenyl C—H bonds of the... 

Alkylations, osmium(ll), 37 348 Alkyl azides, UV spectra, 26 178 Alkylbarium halides, solvated, 11 390 Alkylbery Ilium alkoxides, 11 395 alkylperoxides, 11 395 amides, 11 401 03 anions, 11 369-370 crystal structure of, 11 369 halides, solvated, 11 389 hydrides, 11 371-373 B-Alkylborolane, 16 241... 

The synthetic methods used involve reaction of a cluster anion with [AuCIL], elimination of methane between a cluster hydride and [AuMeL] or addition of LAu+ units to metal-metal bonds. The emphasis here will be on structure and reactions of the complexes. Some examples of mixed gold clusters are given in Table 15, where it can be seen that most work has been on derivatives of clusters of iron, ruthenium and osmium. 

The molecule with X = S is simply and quantitatively made by passing H2S though a refluxing octane solution of Os3(CO)12 (46). The X-ray and neutron diffraction structures of Os3H2(S)(CO)9 (206) and the X-ray structure of the anion [Os3H(S)(CO)9] (207) are known. In the neutral compound the hydride ligands occupy octahedral sites at osmium so that Os—H—Os... 

As in the case of the [K(QNH)]+ salts, the more basic ruthenium anion makes the stronger hydridic-protonic bonds as evidenced by the NMR and infrared spectral characteristics of the ruthenium and osmium salts. 

Although less fully documented than osmium cluster chemistry, rhenium cluster chemistry has been subjected to many structural studies, including those on approximately 20 neutral or anionic carbonyls, particularly carbonyl hydrides [Rev(CO). H ] of nuclearities x = 2 to 6 (Fig. 7). In addition, some ten or more rhenium carbonyl carbides [Rev(CO)vH C] have been shown to contain a core carbon atom, usually occupying a central octahedral site. These systems offer scope not only to explore for rhenium the trends we have already shown for osmium, but also to study the effect on metal-metal distances (and so enthalpies) of such core carbon atoms, which formally donate all four of their valence shell electrons to the cluster bonding. To our knowledge only one rhenium carbonyl cluster compound, Re2(CO)io, has been subjected to calorimetric study to determine its enthalpy of formation. ... 

The anionic hydride species, [Ru3(/x-H)(GO)n] , has been synthesized in a new one-step reaction of Ru3(GO)i2 with 1,3,5-trimethyl-1,3,5-triazacyclohexane (Me3-TAG). The osmium complex can be synthesized in a comparable fashion by reaction of Mc3-TAG with the more labile Os3(GO)io(NGMe)2. " ... 

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