Rhodium complexes mercury

When ethylene was passed into a basic solution of Hg(OAc)2 containing a catalytic amount of [Rh2(OH)3(C5Me5)2]+, ethanol was formed.617 It appears that mercury salts of the type HOCH2CH2HgOAc are formed in a stoichiometric reaction so that this is not strictly a catalytic activation of ethylene by the rhodium complex. 

Alternatively, alkenyl- or alkynyl-mercurials can be methylated in high yield by a stoicheiometric quantity of the readily-available bis(triphenylphos-phine)methyldi-iodorhodium(lll), e.g. (40)->(41). Attempts to perform the methylation with methyl iodide and catalytic amounts of the rhodium complex were less successful because of competing dimerization processes. ... 

Hydrogenation using the rhodium complex may involve the formation of colloid particles, as it was shown that the reaction is inhibited by metallic mercury [167]. Selective hydrogenation of the carbonyl group in a,P-unsatu-rated carbonyl compounds can be done with immobilized ruthenium or iridium complexes by using either the supported aqueous phase technique... 

Complex [(CXI )Ir(/j,-pz)(/i,-SBu )(/j,-Ph2PCH2PPh2)Ir(CO)] reacts with iodine to form 202 (X = I) as the typical iridium(II)-iridium(II) symmetrical species [90ICA(178)179]. The terminal iodide ligands can be readily displaced in reactions with silversalts. Thus, 202 (X = I), upon reaction with silver nitrate, produces 202 (X = ONO2). Complex [(OC)Ir(/i,-pz )(/z-SBu )(/i-Ph2PCH2PPh2)Ir(CO)] reacts with mercury dichloride to form 203, traditionally interpreted as the product of oxidative addition to one iridium atom and simultaneous Lewis acid-base interaction with the other. The rhodium /i-pyrazolato derivative is prepared in a similar way. Unexpectedly, the iridium /z-pyrazolato analog in similar conditions produces mercury(I) chloride and forms the dinuclear complex 204. 

Indirect electroreduction with Ni, Co, and Fe complexes has been well studied, and will be discussed first. Furthermore, the synthetic use of palladium, rhodium, and ruthenium complexes as mediators in the electroreduction of organic compounds are finding increasing apphcations. Metallic complexes derived from chromium, manganese, molybdenum, tungsten, and rhenium have also been used as mediators for special conversions. Recently, tin, zinc, and mercury... 

The substantially larger values of M-p for phosphorus trans to chlorine compared with phosphorus trans to phosphorus correlate with shorter M-P bonds trans to chlorine for a number of metals and oxidation states tungsten(IV), rhodium(I) and (III), platinum(II) and (IV), and linear mercury(II) (15). By analogy with the discussion of the results for the platinum(II) complexes, this indicates the dominance of the (P sMSp)2 term in Equation 1 for couplings with a variety of M, but as discussed earlier it is difficult to determine the extent of variation of... 

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