Organic guest molecules, stabilization

The high thermal stability of zeolites and related micro-porous solids is one of their most attractive features. Whilst it Is clear that materials with organic components cannot withstand ultra-high temperatures, quite respectable compositional stability can be achieved. Thus the [Er(TMA)] polymer mentioned above shows no weight loss in its TGA curve before 550°C. However for porous solids another key issue is that of structural stability. Many open framework coordination polymers lose their crystalline structure upon mild heating, or even evacuation, through loss of guest molecules. 

The properties of zeotype host-guest composites described above - i e, spatial organization, protection and stabilization of guest species - will become more important as molecules exhibit further properties that are essential for their use as materials. The well-developed synthetic methods for molecular compounds allow the preparation of designed molecular entities that possess predictable properties. However, no such thoroughly elaborated synthetic methods are available for the construction of organized arrays of functional molecules in their solid structures [36]. This is cumbersome since often the arrangement of the molecules in their solid compounds is detrimental to the effects (e g. non-linear optical, ferroelectric, electro-optical) that are to be exploited in materials. For example, many structures of molecules in the solid state are centrosymmetric. Also, molecular... 

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