Inert metal complexes trans effects

Similarity with cobalt is also apparent in the affinity of Rh and iH for ammonia and amines. The kinetic inertness of the ammines of Rh has led to the use of several of them in studies of the trans effect (p. 1163) in octahedral complexes, while the ammines of Ir are so stable as to withstand boiling in aqueous alkali. Stable complexes such as [M(C204)3], [M(acac)3] and [M(CN)5] are formed by all three metals. Force constants obtained from the infrared spectra of the hexacyano complexes indicate that the M--C bond strength increases in the order Co < Rh < [r. Like cobalt, rhodium too forms bridged superoxides such as the blue, paramagnetic, fCl(py)4Rh-02-Rh(py)4Cll produced by aerial oxidation of aqueous ethanolic solutions of RhCL and pyridine.In fact it seems likely that many of the species produced by oxidation of aqueous solutions of Rh and presumed to contain the metal in higher oxidation states, are actually superoxides of Rh . ... 

Although in this chapter many aspects of stability have been discussed, there are many others that have not. It is now accepted that for some ligands, metal-ligand double bonding occurs. Just how are bond order and stability related Is the distinction between inert and labile transition metal complexes related in any way to the d-electron configuration of the transition metal (we shall have more to say about this in Chapter 14)7 In addition to the kinetic trans effect, discussed at the end of Chapter 4, there is a static trans effect, sometimes called the trans influence. In this, a metal-ligand bond... 

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