Osmium dodecacarbonyl

HjNiOcjOsjCuHs, Osmium, nonacarbonyl-( tl -cyclopentadienyl )tri- x-hydridonickeltri-, 26 362 H,NiO,Ru,C14H5, Ruthenium, nonacar-bonyl-f-rf-cyclopentadienyl)-tri-p.-hydridonickeltri-, 26 363 H4N, Hydrazine ruthenium(II) complexes, 26 72 H40 20sjCi , Osmium, dodecacarbonyl-tetra- x-hydrido-te/rahedro-tetra-,... 

All three Group 8 metals form trinuclear clusters M3(CO)i2. However, while all carbonyl ligands in ruthenium and osmium dodecacarbonyl complexes coordinate to the metal center as terminal carbonyls, there are two bridged carbonyl groups in iron dodecacarbonyl. This may be due to the smaller van der Waals radius of the iron atom. In this section, Fe(CO)5, Fe2(CO)9and Na2[Fe(CO)4] are reviewed. 

H40,20s4C 2, Osmium, dodecacarbonyl-tetra-p-hydrido-r ra/iedTO tetra-, 26 293, 28 240... 

Os40,2C,2H4, Osmium, dodecacarbonyl-tetra- i-hydrido-tetni6eiiro-tetra>, 26 293 OS4O12S2C12, Osmium, dodecacarbonyldi-/<3-thio-tetni-, 26 307... 

Two significant surveys are published in the sane edition of Coordination Chemistry Reviews. Oxygen donor-ligand derivatives of tri-osmium dodecacarbonyl are covered by Frauenhoff and the reactions of transition metal dihydrogen complexes (of which many are carbonyl-containing) are outlined by Jessop and Morris. The crucial role of matrix Isolation studies is well covered in this article. A shorter review of interest here has been published on the role of the phosphorus d-orbitals in M-P bonding. ... 

Triosmium dodecacarbonyl reacts with the simple ligand vp in an atypical manner 37) the trimeric osmium nucleus is retained and the olefin attacked to give a complex of formula Os3(CO)8(vp), which has two hydrides attached to osmium atoms. These are possibly a and one / -hydrogen of the olefin, the remainder being r-bonded to the trimeric osmium core. 

Ruthenium and Osmium Phthalocyaninates - By cyclization of phthalodinitrile with RuC13(H20)3 or Os04 in the presence of carbon monoxide or with the corresponding trimetal dodecacarbonyls, the pure complexes RuCO(Pc) Py and OsCO(Pc) Py have been obtained in good yields [108]. o-Cyanobenzamide and RuC13(H20)3 [109] produced so-called crude Ru(Pc) and, after extraction with pyridines, complexes like Ru(Pc)Py2. 

Osmium tetraoxide (2 g.) and methyl alcohol (30 ml.) are treated with carbon monoxide (75 atmospheres) at 125° for 12 hours. On cooling, the yellow crystals of dodecacarbonyl-triosmium, Os3(CO)i2, are separated by filtration, washed with acetone, and dried in vacuo (20°, 10-1 mm. Hg). The sample thus obtained is usually sufficiently pure for most purposes. Further purification may be carried out either by sublimation at 130° in vacuo (10 2 mm. Hg) or by recrystallization from hot benzene. The yield of the decacarbonyl is usually in the range 70-80% (1.63 g.). 

H40 20s4C,2, Osmium, dodecacarbonylte-tra-p-hydrido-t ra/ierfro-tetra-, 26 293 H40 2Ru4C,2, Ruthenium, dodecacarbonyl-tetra-p-hydrido-tetra-, 26 262 H40 3P2Ru4Cj<,H.i2, Ruthenium, decacar-bonyl(dimethylphenylphosphine)-tetrahydrido[tris(4-methylphenyl) phos-phitejtetra-, 26 278... 

Bridges between trinuclear metal clusters [of Ru, Os] Synthesis of ruthenium and osmium carbonyl clusters with unsaturated organic rings Oxyligand derivatives of triosmium dodecacarbonyl... 

Among the complexes studied, the rathenium carbonyls were found to be significantly more active than their iridium, osmium, and platinum analogs. The activity reached for triruthenium dodecacarbonyl [Ru3(CO)j2] is stiU one of the highest ever reported in homogeneous WGS. Based on infrared studies of the less reactive iron carbonyl systems, they postulated a mechanism for the WGS reaction that involves addition of a hydroxide anion as the rate-determining step (RDS), as depicted in Figure 16.3. 

Treatment of 5,8-bis(trimethylsilyl)cyclo-octa-l,3,6-triene or 3,5,8-tris(trimethyl-silyl)cyclo-octa-l,3,6-triene with triruthenium dodecacarbonyl gave the pentalene complexes (352 X = H or SiMe ). Tricarbonyl(Ti-cyclo-octa-l,5-diene)ruthenium and tricarbonyl(T)-cyclo-octa-l,3-diene)osmium have been prepared. They react with trityl fluoroborate to give cyclo-octadienylium complexes [(CgHn)M(CO)3] which react with anionic nucleophiles to give neutral compounds, some of which... 

In Table 2.28, the activation parameters observed for the reaction of Os3(CO)io(NCMe) with PPha as well as those obtained for substitution reactions of the trimetal dodecacarbonyls of iron, osmium, and ruthenium are shown. The relatively high activation enthalpies and positive AS values observed in this Table agree with the dissociative mechanism described above. The features in Table 2.28 also reflect the much greater liability of Os3(CO)ii(NCMe) compared with Os3(CO)i2. This probably arises from a weaker bond strength of osmium with acetonitrile than with carbon monoxide. 

In crystalline trinuclear dodecacarbonyls of ruthenium and osmium, the metal atoms form an equilateral triangle by metal-metal bonds. Each metal atom is bound to four terminal carbonyl groups, as shown in Figure 23. Two carbonyl groups are nearly perpendicular to (and the other two are parallel to) the plane of the triangle. 

Os3(GO)ii(NGMe) reacts with thiols, forming (/x-H)Os3(GO)io(/x-SR) clusters through the intermediacy of Os3(GO)ii(HSR) complexes where the thiol is bound to one osmium atom through the S-H bond. " Thioureas also react with triosmium dodecacarbonyl ... 

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