Inorganic complex salts, solid-state

Mechanochemically activated reactions between molecular solids and inorganic salts to obtain complexation and ion segregation in the solid state. 

Lanthanide halides, nitrates and triflates are not only common reagents in organic synthesis (Fig. 1) but also represent, in dehydrated form, key precursor compounds for the more reactive organometallics (Scheme 2). As a rule, in compounds of strong monobasic acids or even superacids, cation solvation competes with anion complexation, which is revealed by fully or partially separated anions and solvated cations in their solid state structures. The tendency to form outer sphere complexation in coordinating solvents [47] is used as a criterion of the reactivity of inorganic salt precursors in organometallic transformations. 

There is a wealth of crystal lattice types of interest in this review. We can differentiate between solid CT complexes and ion-radical salts. The former are the solid-state equivalents of the Mulliken solution CT complexes, and are the "two-chain" crystals. The latter are the so-called "one-chain" compounds, or ion-radical salts, where the organic cation (anion) crystallizes with inorganic anions (cations) as counterions. The crystal structure types have been reviewed by Herbstein [61], Tanaka [62], Soos [63-65] and many others. TaWes 1 and 2 update a classification introduced by Soos [63] and modified later by Wiygul et al. [66]. A few examples are shown diagrammatically in Fig. 4. The IS lattices are the ion-radical salts the IM lattices are the CT crystals, the crystal equivalents of the solution CT complexes. The 2S lattices are the first organic metals found (TTF-TCNQ). 

In the past few years there has been a strong demand for thin solid proton conducting films to build all-solid state electrochemical devices. One obvious way to obtain thin films is to use polymers generally, these polymers have to be modified or mixed with inorganic compounds in order to achieve the required proton conductivity, a similar strategy to that successfully applied to obtain alkali ion conductivity in the polyether/ salt complexes ... 

It is possible to prepare composites of nonconducting polymer/inorganic salt by dispersing inorganic salts in the organic matrix via complexation. The electrical conductivity of such materials has been well established in view of their importance as solid polymer electrolytes in solid state batteries (14J5). 

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