Osmium carbonyl clusters synthesis

Fig.1 Surface-mediated synthesis of osmium carbonyl clusters on the surface of MgO...

Roberto, D., Cariati, E., Ugo, R., and Psaro, R., Surface-mediated organometallic synthesis High-yield preparations of neutral and anionic osmium carbonyl clusters by controlled reduction of silica-supported [Os(CO)3Cl2]2 and OsClj in the presence of Na2C03 or K2C03. Inorg. Chem. 35,2311 (1996). 

Synthesis of poly-aurated high nuclearity osmium carbonyl clusters... 

The Surface of Inorganic Oxides an Unusual Reaction Medium for the High-yield and Selective Synthesis of Various Osmium Carbonyl Clusters... 

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

Quantitative characterization of the formation of [OsjCCCO) from a smaller precursor on MgO was characterized by NMR spectroscopy. The multistep synthesis from Os3(CO)i2 gave [Os5C(CO)iJ2- in a yield of about 65% other products included tri- and tetra-osmium carbonyl clusters (Figure 10.4). The clusters on MgO have been observed by high-resolution transmission electron microscopy (Figure 10.5). ... 

FIGURE 10,4 Synthesis of osmium carbonyl clusters on the surface of MgO the basic properties of the support are essential for the synthesis. A yield of 65% of [Os5C(CO) 4] was obtained, as indicated by NMR spectroscopy. 

Castellanos, R.H., Ocampo, A.L., Moreira-Acosta, J., Sebastian, P.J. 2001. Synthesis and characterization of osmium carbonyl cluster compounds with molecular oxygen electroreduction capacity. International Journal of Hydrogen Energy, 26,1301-1306. 

Rearrangements of clusters, i.e. changes of cluster shape and increase and decrease of the number of cluster metal atoms, have already been mentioned with pyrolysis reactions and heterometallic cluster synthesis in chapter 2.4. Furthermore, cluster rearrangements can occur under conditions which are similar to those used to form simple clusters, e.g. simple redox reactions interconvert four to fifteen atom rhodium clusters (12,14, 280). Hard-base-induced disproportionation reactions lead to many atom clusters of rhenium (17), ruthenium and osmium (233), iron (108), rhodium (22, 88, 277), and iridium (28). And the interaction of metal carbonyl anions and clusters produces bigger clusters of iron (102, 367), ruthenium, and osmium (249). 

The first mixed-metal cluster of Os-Pd, [Os6Pd(bipy)(CO)i8], was reported in 1994, and since then a variety of mixed-metal cluster that contain various Os Pd ratios have been created. Palladium-pyridine complexes appear to be useful reagents in the synthesis of mixed-metal clusters with osmium carbonyl compounds. " The reaction of the coordinately unsaturated cluster [Os3(yu-H)2(CO)io] with [Pd(NH3)2l2] afforded a number of Os-Pd clusters with a high hydride content. " Both palladium phosphine and bidentate phosphine complexes are useful in the preparation of high-nuclearity mixed-metal clusters. The reaction of [Os3(/i-H)2(CO)io] with [Pd2(/i-dppm)2Cl2] gave 258 and 259, in addition to 260, with the same metal core, " in which the molecule contains a twofold symmetry axis. " " ... 

Many carbonyl and carbonyl metallate complexes of the second and third row, in low oxidation states, are basic in nature and, for this reason, adequate intermediates for the formation of metal— metal bonds of a donor-acceptor nature. Furthermore, the structural similarity and isolobal relationship between the proton and group 11 cations has lead to the synthesis of a high number of cluster complexes with silver—metal bonds.1534"1535 Thus, silver(I) binds to ruthenium,15 1556 osmium,1557-1560 rhodium,1561,1562 iron,1563-1572 cobalt,1573 chromium, molybdenum, or tungsten,1574-1576 rhe-nium, niobium or tantalum, or nickel. Some examples are shown in Figure 17. 

Heterometal alkoxide precursors, for ceramics, 12, 60-61 Heterometal chalcogenides, synthesis, 12, 62 Heterometal cubanes, as metal-organic precursor, 12, 39 Heterometallic alkenes, with platinum, 8, 639 Heterometallic alkynes, with platinum, models, 8, 650 Heterometallic clusters as heterogeneous catalyst precursors, 12, 767 in homogeneous catalysis, 12, 761 with Ni—M and Ni-C cr-bonded complexes, 8, 115 Heterometallic complexes with arene chromium carbonyls, 5, 259 bridged chromium isonitriles, 5, 274 with cyclopentadienyl hydride niobium moieties, 5, 72 with ruthenium—osmium, overview, 6, 1045—1116 with tungsten carbonyls, 5, 702 Heterometallic dimers, palladium complexes, 8, 210 Heterometallic iron-containing compounds cluster compounds, 6, 331 dinuclear compounds, 6, 319 overview, 6, 319-352... 

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