Carbonyl complexes cobalt-platinum

In the early work on the thermolysis of metal complexes for the synthesis of metal nanoparticles, the precursor carbonyl complex of transition metals, e.g., Co2(CO)8, in organic solvent functions as a metal source of nanoparticles and thermally decomposes in the presence of various polymers to afford polymer-protected metal nanoparticles under relatively mild conditions [1-3]. Particle sizes depend on the kind of polymers, ranging from 5 to >100 nm. The particle size distribution sometimes became wide. Other cobalt, iron [4], nickel [5], rhodium, iridium, rutheniuim, osmium, palladium, and platinum nanoparticles stabilized by polymers have been prepared by similar thermolysis procedures. Besides carbonyl complexes, palladium acetate, palladium acetylacetonate, and platinum acetylac-etonate were also used as a precursor complex in organic solvents like methyl-wo-butylketone [6-9]. These results proposed facile preparative method of metal nanoparticles. However, it may be considered that the size-regulated preparation of metal nanoparticles by thermolysis procedure should be conducted under the limited condition. 

As has been described, the parent monocarbollide-metal carbonyl piano-stool species 2-(CO)n-closo-2,1 -MCB,0II n] are now known for all of the metals M = Mo (12), W (13), Re (14), Fe (11), Ru (6), Os (8), and Ni (18). Evidence also exists for a dicarbonyl-platinum analogue of compound 18,20 and as mentioned earlier, the manganese analogue of 14 has also briefly been reported.3a A notable absence from this list, however, is any representative of the Group 9 metals. The carbonyl nitrosyl-cobalt complex 21 is very closely related to the hitherto unknown dicarbonyl-cobalt dianion [2,2-(CO)2-< 7<9.v<9-2,1 -CoCB10H 11]2 and this species remains an attractive synthetic target. 

The metal hydride mechanism was first described for the cobalt-carbonyl-catalyzed ester formation by analogy with hydroformylation.152 It was later adapted to carboxylation processes catalyzed by palladium136 153 154 and platinum complexes.137 As in the hydroformylation mechanism, the olefin inserts itself into the... 

FT-ICR, see Fourier-transform ion cyclotron resonance Fullerene[60], germanium-germanium addition, 10, 748 Fullerenes with cobalt, 7, 51 on cobalt Cp rings, 7, 73 inside metallodendrimers, 12, 401 microwave applications, 1, 334 Pd rc-complexes, 8, 348 Ru—Os complexes, 6, 830 with tungsten carbonyls, 5, 687 )2-Fullerenes, with platinum, 8, 634 Fulvalene actinide complex, synthesis, 4, 232 Fulvalene chromium carbonyls, synthesis and characteristics, 5, 264... 

While platinum and rhodium are predominantly used as efficient catalysts in the hydrosilylation and cobalt group complexes are used in the reactions of silicon compounds with carbon monooxide, in the last couple of years the chemistry of ruthenium complexes has progressed significantly and plays a crucial role in catalysis of these types of processes (e.g., dehydrogenative silylation, hydrosilylation and silylformylation of alkynes, carbonylation and carbocyclisation of silicon substrates). 

The peptide bond that is cleaved is the bond between Leu-189 and Asp-190. There are two peptide bonds in close proximity to the iron chelate on Cys-212. The other peptide bond is between He-144 and Gly-145. The Cys-212 sulfur is 5.1 A from the carbonyl carbon of Gly-145, and 5.3 A from the carbonyl carbon of Leu-189. However, the main difference is that the peptide bond of Leu-189-Asp-190 is oriented parallel to Cys-212, while the peptide bond of lie-144-Gly-145 is oriented away for Cys-212. As was seen with cobalt(lll) hydrolysis of peptide bonds, the proximity and orientation of the carbonyl carbon is important for hydrolysis. This approach has been extended to the cleavage of multisubunit proteins. Palladium(n) and platinum(ll) complexes as synthetic peptidases have been reviewed elsewhere. ... 

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