Overview of Structures

This description of the various types of organotin compounds must be supplemented by a description of the structures of the compounds, which are seldom as simple as the above formulae might indicate, and which frequently depend on the physical state of the sample. 

The groups X, however, usually carry unshared electron pairs, and can themselves act as Lewis bases, resulting in intermolecular self-association to give dimers, oligomers, or polymers. Some examples are shown in formulae 1-4-1-6. 

This self-association is governed by the nature of the ligands L and also by the steric demands of R, X, and L, and it is common for the degree of association to increase in the sequence gas solution solid. 

If R or X carries a functional substituent Y beyond the a-position, the alternative of intramolecular coordination can occur leading to the formation of monomers with 5-, 6-, 7-, or 8-coordinated tin. Some examples are shown in formulae 1-7-1-10. 

No Sn(III) radicals have yet been isolated (Chapter 20), though some are known which are stable in solution, in equilibrium with their dimers. Evidence regarding their structures comes mainly from ESR spectroscopy, which shows that, in contrast to carbon-centred radicals which are planar, tin-centred radicals are pyramidal even when the tin carries aryl ligands. 

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This book concentrates on synthesis and identification methods for molecular sieves including nonaluminosilicate molecular sieves and gives a good overview of structures and patented materials. 

Enslein, K. An overview of structure-activity relationships as an alternative to testing in animals for carcinogenicity, mutagenicity, dermal and eye irritation, and acute oral toxicity. Toxicol Industrial Health 1988 4 479-98. 

Burley SK. An overview of structural genomics. Nature Struct Biol 2000 7 (Suppl) 9 3 2—934. 

In this chapter, procedures for drawing molecular structures have been illustrated, and a brief overview of structural inorganic chemistry has been presented. The structures shown include a variety of types, but many others could have been included. The objective is to provide an introduction and review to the topics of VSEPR, hybrid orbitals, formal charge, and resonance. The principles discussed and types of structures shown will be seen later to apply to the structures of many other species. 

Overview of Structural Types for Sulfur-Containing Secondary Metabolites... 

Table 8.1 gives an overview of structural and operational measures that affect the type and course of the in-sewer dry-weather processes. The table exemplifies how process design and operation of sewer networks can be implemented. In other words, it is an overview of methods for wastewater design. ... 

Gladysz JA (2004) Overview of structural classes of ponytails. In Gladysz JA, Curran DP, Horvath IT (eds) Handbook of fluorous chemistry. WUey, Weinheim, Chap 5... 

Grasp carbonyl group basics — get an overview of structure, reactivity, and spectroscopy before delving deeper into aldehydes and ketones, enols and enolates, and carboxylic acids and their derivatives... 

A number of chemical reviews of cuprate superconductors have included the bismuth and thallium families (11)-(14). Reviews focussing on the structural chemistry of these two series are also available (15),(16). On the thallium cuprates, an overview of structural studies has appeared (17), and a detailed review of... 

Woo, Y.-T. (1983) Carcinogenicity, mutagenicity and teratogenicity of carbamates, fhiocarbamates and related compounds an overview of structure-activity relationships and environmental concerns. Environ. Carcinog. Ecotoxicol. Rev., Cl (1), 97-133. 

In the overview of structure-property relationships that follows, it should be borne in mind tliat these comparisons are (wherever possible) for those materials where hydrogen has been replaced with fluorine. Cases in the literature where dramatically different monomer structures are used for the fluorinated and unfluorinated polyimides cannot easily be interpreted for effects of fluorine, although such comparisons are often casually made in the literature anyway. For instance, to ascribe die property differences in PMDA-ODA and 6FDA-0DA to fluorine substitution is of little value toward understanding the effect of fluorine, though this is often die extent to which data are available. 

For a recent overview of structure and hydrogen bonding in the organic solid state, see Chem. Materials, Special Issue 1994,6, No. 8. 

Figure 1. Overview of structure-based drug design If the three dimensional structure of the target macromolecule is known by X-ray crystallography, NMR, or even homology modeling [7], this can serve as a starting point for what has been termed direct structure-based drug design [8]. This class of problems is usually referred to as receptor-based...

This chapter presents an overview of structures, properties, synthetic methods and applications in catalysis for highly dispersed metal oxides, with special attention given to recent developments in nano-scale metal oxides. 

Thus, much of the original work on the stmctural chemistry of the actinide (III) and (IV) orthophosphates is presented in the above-mentioned reviews incompletely some of the reviews include only earlier published works. In this chapter, we shall present a general overview of structural information on the known (up to 2005-2006) anhydrous actinide (III) and (IV) orthophosphates (and some of their structural analogues with tetrahedral oxoanions XO4 with X = Si, V, As, V). 

Brief Overview of Structural Features of Selected Classes of Carcinogenic Pesticides... 

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