Scope of the review

The theoretical study of any chemical problem which falls within the domain of the Bom-Oppenheimer approximation involves two basic steps (a) the solution of Schrodinger s electronic equation, equation (5), for one or more electronic states over the range of nuclear configurations demanded by the problem and (b) solving the nuclear equations of motion on the potential energy surface, or surfaces, thus obtained.  

The calculations in part (b) may be of two types the determination of the nuclear energy levels for bound states of the system, i.e. the quantized vibrational and rotational levels of the system, or the study of the dynamics of the chemical changes described by the surface in terms of quantum reactive scattering or classical trajectory calculations. 

It is the purpose of this review to discuss and illustrate the methods presently employed to obtain potential energy surfaces by approximate, but non-empirical solutions to Schrodinger s electronic equation. In addition to discussing the different levels of approximation employed in these ab initio calculations, we emphasize the type of chemical system (in terms of its electronic structure) to which each level of calculation may be expected to yield usable results, i.e. results with acceptable errors or with predictable bounds on the error. Our interest will be primarily in surfaces which have been determined for the prediction and understanding of chemical reactions. This will include a survey of those calculations which have concentrated on determining the reaction path, and the geometry and properties of the system at points on this path, as well as those in which an essentially complete surface has been determined. The latter type of calculation coupled with either classical or quantal treatments of the nuclear motion on such a surface provides a total theoretical prediction of a chemical reaction. This ultimate objective has been achieved in the case of the H + Ha exchange reaction. 

A recent review of the dynamics of bimolecular reactions by Polanyi and Schreiber14 provides a detailed account of the classical trajectory method for treating the motion of a reactive system on a potential energy surface. Such classical motion studies on three-dimensional surfaces are now commonplace and have yielded a great deal of information regarding the microscopic dynamical behaviour 

Polanyi and J. L. Schreiber, Physical Chemistry - An Advanced Treatise, ed. H. Eyring, W. Jost, and D. Henderson, Academic Press, New York, 1974, vol. 6. 

In view of the Remark in Section 10.1.5.2, we find it convenient to consider the communal entropy rather than the total or configurational entropy to study the glass transition. The configurational entropy can be broken into a sum of three terms (10.19), each of which must be independently nonnegative. As soon as one of 

2004PHC431, 2005PHC389) discussions. The specialized review (1993H601) surveyed the synthesis of 1,5-benzodiazepines with three-, four- and five-membered rings fused to different positions of the 1,5-benzodiazepine skeleton. Synthesis of DNA-interactive pyrrole[2,l-c][l,4]benzodiazepines (1994CR433) and medicinal chemistry aspects of the novel thieno benzodiazepine antipsychotic Olanzapine (1997MI1743) have been reviewed. 

Current work is focused on the benzoheteropines with the fused pyrrole (or indole), thiophene or furan rings, i.e., ortho-fused 6 + 7 + 5 ring systems with carbons only on the six-membered ring, one heteroatom on the five-membered ring and one or more heteroatoms on the seven-membered ring. The variety of heteroatoms is limited to nitrogen, oxygen and sulfur. Several examples of the related cyclic systems with the other heteroatom distribution or peri-fusion are briefly summarized in Section 4.3. The current first specialized review covers synthetic, reactivity and structural aspects reported from the late 1989 until 2007. 

We confine attention to macrocyclic polythioethers that contain at least three Sulfur atonis within the macrocyclic ring and have at least two methylene units between S atoms (i.e., excluding dithioacetals). The review discusses neither sulfur-containing cyclophanes nor their metal complexes. 

For several reasons we further restrict consideration to those compounds that comprise solely thioethers as donor groups. First, complexes of such compounds most clearly evince the electronic consequences of thioether coordination. Second, homogeneity of donor group simplifies analysis of conformation. Such studies provide the trends and general principles for interpretation of the coordination chemistry of mixed donor macrocycles. Third, the surge of research effort in all-thioether macrocycles has yielded sufficient information to permit detailed comparisons between complexes of closely related Ugands inclusion of mixed-donor macrocycles contributes little to such discussion. 

We name the crown thioethers non-systematically by an extension of the crown nomenclature introduced by Pedersen [1]. Thus 1,4,7,10,13,16-hexathiacyclo-octadecane is called hexathia-18-crown-6. This name is often further abbreviated to 

where the numbers denote the ring size and number of sulfur atoms, respectively. This nomenclature rarely leads to ambiguity since most crown thioethers used as ligands feature the most symmetric possible disposition of donor 

---

With the publication of Vol. 51 we should also like to refer to editorial policy this series publishes invited, critical review articles of new developments in all areas of Polymer Science in English (authors may naturally also include works of their own). The responsible editor, that means the editor who has invited the article, discusses the scope of the review with the author on the basis of a tentative outline which the author is asked to provide. Author and editor are responsible for the scientific quality of the contribution the editor s name appears at the end of it. Manuscripts must be submitted, in content, language and form satisfactory, to Springer-Verlag. Figures and formulas should be reproducible. To meet readers wishes, the publisher adds to each volume a volume index which approximately characterizes the content. 

Over the last decade a number of high oxidation state ruthenium porphyrin complexes containing 0x0 or imido ligands have been reported and have been thoroughly studied for their role in oxidation and atom-transfer chemistry. Although comparisons can be drawn with organometallic species (carbene, imido. and 0x0 ligands are formally isolobal) the chemistry of the 0x0 and imido complexes is beyond the scope of the review and will not be covered here. 

In the sections above, only infinite planar interfaces between air and an aqueous phase or two immiscible liquids like water and DCE were considered. Reducing the question to this class of surfaces only would be a severe limitation in the scope of the review as more reports appear in the literature debating on the SH response from small centro-symmetrical particles [107-110]. It is the purpose of this section to discuss the SHG response from interfaces having a radius of curvature of the order of the wavelength of light. 

With some exceptions (2-4), there have been relatively few recent reviews of microanalysis that have considered applications to plant science. In a previous review of this topic (5), I concentrated almost entirely on methods of specimen preparation for electron probe X-ray microanalysis. Here I highlight further developments in this area, and also broaden the scope of the review to include other microanalytical techniques. This chapter introduces the main types of hardware that are now available for microanalysis, reviews the main techniques used to prepare plant material prior to analysis, and provides protocols for the two major techniques. 

Contents Scope of the Review. Experimental Methods. Glass Transitions. Melting. Crystallization. 

This chapter covers only the chiral compounds that are cited in the literature by virtue of their optical activity. To keep the chapter to an acceptable length, a discussion of the stereochemical properties of sulfenamides showing axial chirality is omitted (17). Similarly, to limit the scope of the review, the chemistry of penicillin, cephalosporin sulfoxides and related compounds (14,18,19), steroidal sulfoxides (15,16), and other naturally occurring chiral sulfur compounds (4) is not discussed. For the same reason, only selected results are discussed and in some cases only references are given to recent papers and review articles on special topics. 

Scope of the Review Paper. - From the above reasoning it is clear that over the past decades a large number of studies have been reported on supported cobalt F-T catalysts. All these studies indicate that the number of available surface cobalt metal atoms determines the catalyst activity and attempts to enhance the catalytic activity have been focusing on two interconnected issues (1) to reduce the cobalt-support oxide interaction and (2) to enhance the number of accessible cobalt atoms available for F-T reaction. It has been shown that the number of catalytically active cobalt atoms as well as their selectivity can be largely enhanced by the addition of small amounts of various elements, called promoters, to the catalyst material. The exact role of these promoters - as is the case for many other heterogeneous catalysts as well -remains often, however, unclear. 

There has been much interest in flow and flow orientation effects with polymer melts containing anisometric particles which may be plate-like or fibrous. Flow-induced orientation of short reinforcing fibres is an area of considerable commercial importance, which is beyond the scope of the review [30]. 

The last two decades of research on high performance rigid-rod polymers and molecular composites have produced a wide variety of material systems for evaluation. The purpose here is not to present a comprehensive review but rather to describe these relatively recent research developments with regard to the synthetic methods and approaches that have been utilized. In doing this some properties of the polymers are discussed as well as some of the problems encountered in conjunction with their synthesis and evaluation. In an effort to limit the scope of the review, we will address only aromatic heterocyclic rigid-rod polymers, extended chain polymers and derived molecular composites. 

The design reviews clearly indicate the scope of the review and actions decided. 

Reference to all the spectra of the numerous phenanthrolines that have been examined is beyond the scope of the review. This section covers studies on the parent phenanthrolines and gives key references to substituted derivatives. Several references to spectral data that are of especial value in particular applications, such as structure elucidation, are mentioned in later sections of the article. 

We would like to apologize to those scientists whose work may not have appeared in this review either due to the limited scope of the review or oversight. We gratefully acknowledge the financial support for our spiro-(3-lactam research programme from Council of Scientific and Industrial Research, New Delhi and Department of Science and Technology (DST), New Delhi, Government of India (Project No. SP/S l/G-50/99 and SR/FTP/CS-135/2006). 

---