Scope of the Article

Perhaps the most striking applications are in the interactions of biological molecules, where biological recognition of one biomolecule by another, or set of others, is highly specific as to chirality as well as to composition. Discrimination here appears in extreme form. Examples are discussed in 1.12, after a review of the results in more conventional systems. 

A molecule is chiral or handed if it is not superposable on its mirror image. The general criterion for chirality is that a molecule must not possess an improper axis of rotation In particular it must not possess either a centre of inversion (improper rotation axis with zero angle) or a plane of symmetry (improper rotation by 7t). 

Discriminatory interactions of chiral molecules, whidi are the subject of this review, manifest themselves under many different circumstances among assemblies of molecules of different chirality such interactions are general. The first section of this review will be devoted mainly to a survey of the phenomena arising from chiral discrimination the second to a detailed theoretical treatment of the origin and nature of the discriminating interactions. 

We have suggested the former because of its explicit reference to chirality. The possible chirodiastaltic interactions classified under (a) and (b) may be represented schematically as follows  

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This article is an attempt to provide a guide to the nomenclature of heterocyclic compounds. The various systems available will be described, and problems associated with their use will be discussed. Where appropriate, the advantages and disadvantages of particular systems will be mentioned. In the interests of precision and conciseness, nomenclature rules themselves are not framed in a readily digestible form they are meant not for reading, but for reference. It is hoped that the following text will be more readily assimilable, and, in conjunction with the original rules (the most relevant of which are provided here as an Appendix), will enable the reader to name the majority of heterocyclic molecules. However, it is beyond the scope of the article to cover all possible heterocyclic structures in cases where the text proves inadequate, reference to the rules themselves will be necessary. 

Routes to monomeric , mononuclear , monolanthanide alkoxides, enolates, siloxides and aryloxides - an expanded title which will put the scope of the article in a more concrete form. The synthesis of mononuclear alkoxides, in particularly homoleptic derivatives [1], was decisively stimulated by the discovery of high temperature superconducting ceramics based on YBa2Cu307<, where yttrium represents the lanthanide elements [2]. The support of volatile and highly soluble molecular precursors is a prerequisite for synthesizing thin films of these materials by means of MOCVD [3] and sol gel processes [4], respectively. More recently, lanthanide alkoxide reagents became established in... 

Bimetallic and trimetallic compounds with bridging ligands encompass a general theme in chemistry, which is far too wide to be justifiably dealt with in a single article. The range of complexes, which qualifies for inclusions, is very diverse and often unrelated. For this reason we have decided to limit artificially the scope of the article by excluding certain areas which have been reviewed extensively. Therefore, the following selection criteria were enforced when material was collected. 

The scope of the article requires, first, a brief summary of the nature of DMSO as a ligand in coordination compounds. The discussion is then divided into simple complexes containing DMSO as the only donor ligand and the recently-developed mixed amine-sulfoxide complexes, where DMSO plays the role of the leaving group. 

The fundamental role that the interactions with the solvent as well as with the counterion play in determining the rate of anion-promoted reactions is well known. This class of reactions is of primary importance in organic and industrial chemistry. The effect of the medium can be quantified by comparing the reactivity in the condensed phase with that in the gas phase, where in the absence of any solvation, the "intrinsic" reactivity of the "naked" anion is observed. The goals of this entry are to briefly summarize the research on anion activators and activation. The scope of the article is necessarily limited and readers are urged to use the citations for more information. 

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