Guests inorganic

Heterogeneous matrices are usually called mixed or hybrid matrices and are prepared by dispersing guest inorganic fillers in host organic films (Fig. 5.1). 

For microporous compounds with special compositions, calcination effects are even more severe. As compared with zeolites, these compounds have lower thermal stability. Strictly speaking, most of them are nonporous since removal of the occluded guest molecules by calcination usually results in collapse. This is due to strong H-bonds with the framework, coordination bonds, and sometimes the templating molecule is shared with the inorganic polyhedra. Relevant examples of low-stability microporous compounds with interesting structural features are zeolitic open-framework phosphates made of Ga [178], In [179], Zn [180], Fe [181],... 

The electrochemical intercalation/insertion is not a special property of graphite. It is apparent also with many other host/guest pairs, provided that the host lattice is a thermodynamically or kinetically stable system of interconnected vacant lattice sites for transport and location of guest species. Particularly useful are host lattices of inorganic oxides and sulphides with layer or chain-type structures. Figure 5.30 presents an example of the cathodic insertion of Li+ into the TiS2 host lattice, which is practically important in lithium batteries. 

Recently, Astruc et al. [189] reported novel amido-ferrocene dendrimers (e.g., 91) which were shown to act as supramolecular redox sensors for the recognition of small inorganic ions (Fig. 41). It was further observed that as the den-drimer generation number increased the sensitivity to the guest molecules also increased as observed by cyclic voltammetry experiments. 

Host-guest interactions. The area of host-guest chemistry encompasses the complexation by organic hosts of a range of both organic and inorganic guests. 

It should be noted that molecular complexes of the cyclodextrins may be isolated as crystalline solids for example, a crystalline complex is obtained with iodine (which resembles the well known blue complex between iodine and starch) as well as with a large number of other inorganic and organic guests. 

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