Three-dimensional structures inorganic compounds

Because the number of protein three-dimensional structures completed is relatively small, much of our understanding of the metal center structures comes from studies on inorganic model compounds. Although it is beyond the scope of this chapter to discuss these compounds separately, we have integrated some of the results in our discussion of the relevant protein structures. 

This chapter reviews the literature up to approximately January 1984. Previous comprehensive reviews of the chemistry of zirconium and hafnium are available, and annual surveys of the inorganic and coordination chemistry of these elements have been published since 1981 The present treatment emphasizes the chemistry of discrete, isolable complexes, although some attention has been given to the extremely complex aqueous solution chemistry of Zr and Hf. In general, zirconium forms slightly more stable complexes in solution than does hafnium stability constants may be found in standard compilations.In cases where the structural chemistry of discrete complexes is closely related to that of chain, layer or extended three-dimensional structures, the discussion of the discrete complexes has been set in the broader context the section on fluorometallate complexes is a case in point. Organometallic compounds of zirconium and hafnium have been excluded almost entirely. 

The process of ion-exchange was first discovered and studied in natural inorganic compounds, of which the most abundant are the clay minerals, especially zeolites. The latter are microporous, crystalline aluminosilicate minerals. Numerous naturally occurring and synthetic zeolites exist, each with a unique three-dimensional structure that can host cations, water, or other molecules in its void space (cavities or channels). 

Cambridge Structural Database Chemical Abstracts Service Information System Factual Information Databases Inorganic Compound Representation Inorganic Three-dimensional Structure uiatabases Online Databases in Chemistry. 

Chemical Attracts Service Information System Combinatorial Chemistry Factual Information Databases Grtqth Theory in Chemistry Inorganic Compound Representation Reaction Databases Ring Perception Stereochemistry Representation and Manipulation Structural Similarity Measures for Database Searching Structure Databases Structure Representation Three-dimensional Structure Searching. 

In contrast to applications in structural biology where X/Y correlations are nowadays normally executed as H detected, three-dimensional experiments because of sensitivity reasons,14 many studies on inorganic or organometallic compounds are still performed as two-dimensional experiments with direct detection of one heteronucleus and under -decoupling. As compared to these two categories, one-dimensional polarisation transfer methods such as (semi) selective X/Y-INEPT or INDOR-type techniques, which had in the past been shown to be particularly useful for the characterisation of substrates with only one or two heteronuclei,11 have recently received less attention.15 NOE-based correlations, which are frequently employed for the structure elucidation of bio-molecules, remain rare, and apart from an earlier report of a 13C/6Li HOESY experiment,16 have not been further investigated. 

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