Carbon monoxide complexes

Conditions of high pressure and low temperature favor the formation of the complex, whereas low pressure and high temperature tend to release the complexed carbon monoxide from solution. These conditions typify the operation of the absorber-stripper shown in Figure 2. Specific design conditions for the process are given in references 86—88, and an excellent summary of processing considerations is presented in reference 85. 

The key steps in the reaction are addition of hydridorhodium to the double bond of the alkene and migration of the alkyl group to the complexed carbon monoxide. Hydrogenolysis then leads to the aldehyde. 

Aluminium chloride-nitromethane complex, Carbon monoxide See Aluminium chloride-nitromethane Carbon monoxide, etc. 

It appears that the metal-ligand bonds in carbonyl and dinitrogen complexes are similar but somewhat weaker in the dinitrogen complexes. Carbon monoxide is no only a better cr donor but also a better ir acceptor. This is 10 be expected on the basis of whatever polarity exists in the CO molecule (see Fig. 5.18) and the fact that the ir antibonding orbital is concentrated on the carbon atom (see Fig. 5.20), which favors overlap with the metal orbital. The superior r accepting ability of CO also accounts for the instability of carbonyl dinitrogen complexes. Both Cr(CO)sN2 and cis-... 

Organom etallic Compounds. Organometallic complexes of platinum are usually more stable than palladium complexes. Carbon monoxide complexes of platinum are formed more readily than with palladium. Mononuclear and polynuclear complexes in oxidation states 0 to +2 exist such as... 

In the presence of catalytic amounts of palladium complexes, carbon monoxide with ylides of the general formula PhI=NS02Ar afforded arylsulphonyl isocyanates (isolated as N-aryl-N -2-chlorophenylureas, on reaction with 2-chloroaniline) [53] ... 

Step (1) involves the formation of methyl iodide, which then reacts with the rhodium complex Rh(I)L by oxidative addition in a rate-determining step (2) to form a methylrhodium(III) complex. Carbon monoxide is incorporated into the coordination sphere in step (3) and via an insertion reaction a rhodium acyl complex is formed in step (4). The final step involves hydrolysis of the acyl complex to form acetic acid and regeneration of the original rhodium complex Rh(I)L and HI. Typical rhodium compounds which are active precursors for this reaction include RhCl3, Rh203, RhCl(CO)(PPh3)2, and Rh(CO)2Cl2. 

In further investigations it was possible to show that -butyl lithium is also able to complex carbon monoxide On warming to -30°C the CO molecule inserts into the lithium-carbon bond in contrast to the silicocene case and even this pentoyl lithium intermediate decomposes at -20°C ... 

Tran PD, Le Goff A, Heidkamp J, Jousselme B, Guillet N, Palacin S, Dau H, Fontecave M, Artero V (2011) Noncovalent modification of carbon nanotubes with pyrene-functionalized nickel complexes carbon monoxide tolerant catalysts for hydrogen evolution and uptake. Angew Chem Int Ed 50(6) 1371-1374. doi 10.1002/anie.201005427... 

Reductive coupling reactions, titanium complexes Carbon monoxide insertion, titanium complexes Acetylene insertion, titanium complexes Carbon dioxide insertion, titanium complexes Isocyanide insertion, titanium complexes Carbonylatlon, titanium alkyls... 

Figure 5.5. Diagram of energy profile (dotted line) as molecular oxygen reacts with a surface of carbon to form surface oxygen complexes, carbon monoxide, and carbon dioxide. describes activation energies of intermediate stage reactions.

In this region are found triple bonds (X=Y) and cumulated double bonds (X= Y=Z). The bands of the latter tend to have considerably more intensity than the former. A combination band in primary amine salts occurs here. Metal carbonyl complexes (carbon monoxide complexes) absorb strongly in the lower part of the region. 

A related version of great economic interest is the Fischer-Tropsch process for reductive conversion of carbon monoxide to hydrocarbons. This reaction is catalyzed by a number of metals but cobalt and iron have been most closely studied. The key reaction steps are reduction of metal-complexed carbon monoxide and carbonyl insertion reactions. The hydrocarbon chain is built up by a series of successive carbonyl insertion and reduction steps. 

Metal carbonyls are particularly convenient starting materials for the preparation of n bonded hydrocarbon complexes. Carbon monoxide is replaced by the unsaturated hydrocarbon ligand. The volatility of the displaced carbon monoxide, which allows it to be removed readily from the reaction mixture, must assist the reaction. 

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