Anation solid state

House, J. E. (1993). "Mechanistic Considerations for Anation Reactions in the Solid State." Coord. Chem. Rev. 128, 175-191. 

The most common reaction exhibited by coordination compounds is ligand substitution. Part of this chapter has been devoted to describing these reactions and the factors that affect their rates. In the solid state, the most common reaction of a coordination compound occurs when the compound is heated and a volatile ligand is driven off. When this occurs, another electron pair donor attaches at the vacant site. The donor may be an anion from outside the coordination sphere or it may be some other ligand that changes bonding mode. When the reaction involves an anion entering the coordination sphere of the metal, the reaction is known as anation. One type of anation reaction that has been extensively studied is illustrated by the equation... 

An anion effect is also reported for the solid-state anations of cis-[Co(en)2(py)X]Y2 (X- = Cl-or Br- Y- = Br" or I"). Experimental conditions affect activation parameters, and the kinetic compensation effect is observed (that is, a is linearly correlated with log A). However, the correlation is different for [Co(en)2(py)X]Br2 than for [Co(en)2(py)X]I2.71 This result suggests that the chemical process of importance is anion-dependent. It is proposed that the Co—py bond strength is affected by polarization effects due to the surrounding ionic halides. 

Dehydration-anation reactions of coordination compounds. House [174] has proposed a general mechanism for the solid state dehydrations and anations of coordination compounds. The generation of point defects, analogous to Schottky or Frenkel defects (Chapter 1), is considered as the transition state. Reactions with low , values may occur by an S l dissociative mechanism and reactivity is influenced by the availability of free space in the crystal structure. Corbella and Ribas [175] found support for such mechanisms [174,176],... 

Substitution reactions of [Ru(NH3)jOH2] have been reported (Table 3). Thermolysis of [Ru(NH3)jOH2]X3 in the solid state takes place via a two step process to give initially [RuX(N-H3)50H2] in a rate-determining step, with subsequent formation of [RuX(NH3)5] " (X = Cl", Br", 1", N03") the activation energies and entropies for these reactions have been asses-sed. In solution, anation of [Ru(NH3)sOH2)] shows second order kinetics.The photolysis of [Ru(NH3)5(OH2)] has been reported. ... 

Dealkylation ligands, 432 Deamination solid state anation, 469... 

A particularly useful synthetic route is the solid-state dehydration-anation process (I5)< 37.i38) ambidentate ligands, then bridging dinuclear... 

Many reactions are known in which a volatile ligand is removed from the coordination sphere and replaced by an anion. The volatile ligands involved in these anation reactions have included water, ammonia, pyridine, ethylenediamine, 2,2 -bipyridine and dimethylformamide. Any complex cation containing one or more volatile ligands might be expected to undergo a solid-state anation reaction. The recent book by Wendlandt and Smith on the thermal properties of transition-metal complexes contains numerous examples. ... 

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