Actinide complexes kinetic stability

The primary reason for the thermal stability or instability of the alkyls and aryls of the lanthanides and actinides is kinetic in nature. As in all kinetic processes, the rate of reaction is dependent upon the activation energy between reactants and products. By considering the various decomposition pathways and factors which enhance or inhibit these pathways one can rationalize the observed sta-bihties of the various complexes. 

The extensive chemistry of amido complexes, and, more particularly, of alkylamido complexes, reveals that the planar form is almost invariably found, along with bridging amides (221). Much attention has been paid to the synthesis of metal amido complexes of early transition metals, lanthanides and actinides. The amido group, particularly where it is bulky, confers unusual low coordination numbers on the metals and can also produce materials with considerable kinetic stability toward attack by nucleophiles (42, 67). However, the relevance of this extensive and fascinating chemistry to nitrogen fixation is somewhat problematic. 

Actinide complexes, 1129-1220 coordination numbers, 1131 geometry, 1131 kinetic stability, 1130 steric effects, 1130 Aciinide(III) complexes, 1131-1136 amides, 1133 ammines, 1131 antipyrine, 1134 aqua,1133... 

Carbonate complexes analogous to those found for the various oxidation states of uranium are to be expected for other actinides. Their stabilities certainly depend mainly upon the oxidation state and hence do not differ very much from what has been found for the analogous uranium complexes [248]. Maya [272] and Wester and Sullivan [274] determined the Np(vi)/Np(v) and Pu(vi)/Pu(v) potentials respectively in carbonate media. Electrochemistry, equilibria, and kinetics of actinide carbonate complexes have been critically reviewed [271]. 

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