Ruthenium carbonyl clusters carbides

The formation of carbido-carbonyl cluster compounds with ruthenium and osmium appears to be common in pyrolysis reactions the basic reaction may be viewed as the transformation of the coordinated carbon monoxide to carbide and carbon dioxide. Small variations in... 

Exclusive of metal-metal bonding, the six metal atoms in the octahedral cluster metal carbonyls Mg(CO)10 (M = Co, Rh, and Ir) as well as their iso-electronic analogs Me(CO)i52 and Mg (CO) have (6)(9) + (2)(16) = 86 outer valence electrons. The hydride H2Rug(CO)i0 and the carbide Rug(C0)i7C are two types of octahedral cluster ruthenium carbonyl complexes that likewise have 86 outer valence electrons exclusive of metal-metal bonding and thus may be regarded as isoelectronic with Mg(CO) g (M = Co, Rh, and Ir). 

The large number of derivatives of 1 and 2 in which the ruthenium core is preserved indicates that the presence of a carbide atom makes a significant contribution to the stability of the cluster.24 Single crystal X-ray diffraction studies of some derivatives of 1 and 2 reveal that the carbide atom is located slightly closer to the new ligand. This has been attributed to an electronic compensatory effect of the carbide atom when the carbonyl ligands are replaced by poorer 77-acceptor ligands.25... 

Carbide, iron complex, 26 246 Carbido carbonyl ruthenium clusters. 

The recently reported carbide clusters of ruthenium, Rue(CO)i7C and Ru6(CO)i4(arene)C (211), provided a good example of the power of mass spectrometry as an analytical tool. The appearance of the ions Rug(CO) C+ (n = 0-17) provided a clear differentiation between Rue(CO)i7C and another proposed formula Rug(CO)i8 (324). The first carbonyl oxide cluster 0s3(C0)i2 0s04 was characterized by its mass spectrum. The ions 0s404(C0),i+ (n = 0-12) occur in high abundance and the tetranu clear cluster does not rupture until all CO groups are lost (219,220). Other clusters which have been characterized by mass spectrometry include Os3(CO)io(OMe)2 (217), Ru3(CO)i2Xg (X = Cl, Br, I) (212),... 

The octahedral cluster ruthenixnn carbonyl carbide (Ru0(CO)i7C) has been known for a longer time and thus has been studied in somewhat more detail. Pyrolysis of Ru3(CO)i2 about 150°C in hydrocarbon solvents was reported to give a deep red, air-stable solid, first (319) mistakenly called Ru0(CO)i0 but later (357) correctly identified as Ru0(CO)i7C on the basis of its x-ray crystal structure. The single carbon atom in RU0(CO)i7C is imbedded in the center of a ruthenium octahedron with ruthenium-ruthenium bonds along the... 

In contrast to [Fe4H2(CO)i3], the analogous hydrides of ruthenium or osmium are stable. Besides tri- and tetranuclear clusters, also known are clusters containing five or six iron or ruthenium atoms and from five to eight osmium atoms as well as carbonyl carbide clusters in which metal atoms are bonded to the carbon atom (Figure 2.22) [Fe5(CO)i5C], [Fcs CO),CV-, [Ru5(CO)i5C],... 

The same kind of observation was made recently by D. Dombeck [31] of Union Carbide for the same reaction using ruthenium clusters. In the case of ruthenium there is, under catalytic conditions, evidence for the presence of [HRu3(CO)ii] HRu(CO)4 and Ru(CO)3lJ. An almost complete catalytic cycle has been established by Dombeck. It appears that the hydrido anionic cluster [HRu3(CO)ii]" or HRu(CO)7 make a nucleophilic attack at CO coordinated to the mononuclear carbonyl Ru(II) complex to give a formyl species. The reaction, here, would obey a very complex mechanism involving both mononuclear and polynuclear species. This phenomenon seems to be a general rule in many reactions involving CO. 

C, Carbide iron complex, 26 246 ruthenium cluster complexes, 26 281-284 CHF,02, Acetic acid, trifluoro-tungsten complex, 26 222 CHFjOjS, Methanesulfonic acid, trifluoro-iridium, manganese, and rhenium complexes, 26 114, 115, 120 platinum complex, 26 126 CH2O2, Formic acid rhenium complex, 26 112 CH, Methyl iridium complex, 26 118 manganese complex, 26 156 rhenium complexes, 26 107 CHjO, Methanol platinum complexes, 26 135 tungsten complex, 26 45 CNajOuRusCn, Ruthenate(2- )ns-carbido-tetradecacarbonyl-disodium, 26 284 CO, Carbonyls chromium, 26 32, 34, 35 chromium, molybdenum, and tungsten, 26 343... 

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