bluuebunny/crossref_metadata_2025 huggingface dataset:
Nematoida
Authors: Brusca Richard C. , Giribet Gonzalo , Moore Wendy
Published: September 2023

This chapter discusses the phylum of Nematoida. Nematoida is one of the main lineages of Ecdysozoa, the others being Panarthropoda and Scalidophora, although the latter may also be a grade. Adults in both phyla Nematoda and Nematomorpha share a special cuticle, mostly without chitin and neither phylum has protonephridia, and both lack circular musculature in the body wall. The chapter then explores the classification, life cycles, and body plan of phylum Nematoda and Nematomorpha. The field of nematology is in urgent need of a new phylogenetic system, given the conflict between the traditional taxonomy of the group and the phylogenetic history of the clade.
Turtles
Authors: Harvey Pough F. , Bemis William E. , Mcguire Betty , Janis Christine M.
Published: September 2023

This chapter notes the unique structure of turtles. The unique body form of turtles makes them immediately recognizable, but their anatomical rearrangements have obscured morphological characteristics which are used to determine evolutionary affinities among other vertebrates. The shells of different turtle species reveal their habitat and lifestyle of living in terrestrial, freshwater and marine environments. The chapter discusses the form, diversity, social behavior, reproduction, and migration of turtles. It then acknowledges how more than half of the extant species of turtles are facing extinction as they are not safe from humans even though they are relatively safe from natural predators.
Crocodylians
Authors: Harvey Pough F. , Bemis William E. , Mcguire Betty , Janis Christine M.
Published: September 2023

This chapter provides an overview of extant crocodylians. The group of crocodylians include the largest extant species of reptiles and the only ones that sometimes regard humans as prey. Moreover, all extant crocodylians are semiaquatic predators and nearly all live in the tropics or subtropics. Contrary to the impression that comes from seeing well-fed captive alligators and crocodiles resting inert for hours, free-living crocodylians have extensive and complex repertoires of predatory, social, and parental behaviors. The chapter then cites habitat loss, alteration and alien species, and unregulated exploitation of wild populations as some of the threats to the crocodylian species.
Extant Birds
Authors: Harvey Pough F. , Bemis William E. , Mcguire Betty , Janis Christine M.
Published: September 2023

This chapter focuses on the taxonomic diversity of extant birds. It shows how extant birds are divided into Paleognathae and Neognathae, in accordance with their palatal anatomy. The main characteristics of birds include flight at a structural level and diurnality and this has played a significant role in their lives. The chapter details the myriad structural specializations for flight, bipedalism, and feeding that have produced this diversity before considering sensory systems, reproduction, and behavior. It also looks into how declines in abundance can influence species-typical songs of birds, citing how declines in abundance occurred across all biomes aside from the wetlands.
Therians
Authors: Harvey Pough F. , Bemis William E. , Mcguire Betty , Janis Christine M.
Published: September 2023

This chapter tackles the evolutionary history of Theria and its two clades, Marsupalia and Eutheria. Therians are viviparous amniotes which give birth to young after a period of internal gestation. Although most therians are terrestrial, there are also therians with burrowing, aquatic, and flying forms. Thus, the evolution of these different ways of life led to corresponding diversity in anatomy, body size, and ecology, as well as many striking cases of convergent evolution. The chapter considers the diversity of Metatheria and Eutheria in relation to the key elements of therian reproductive biology and specializations for feeding and locomotion. It notes how mammals front extinction risk at the hands of humans, which includes habitat loss and the introduction of alien species.
The Making of a Body and a Field
Authors: Barresi Michael J. F. , Gilbert Scott F.
Published: September 2023

This chapter considers the life cycle as a central unit in biology. It explains the basic animal life cycle, which consists of fertilization, cleavage, gastrulation, germ layer formation, organogenesis, metamorphosis, adulthood, and senescence. It also outlines three germ layers that give rise to specific organ systems: the ectoderm that gives rise to the epidermis, nervous system, and pigment cells; the mesoderm that generates the kidneys, gonads, muscles, bones, heart, and blood cells; and the endoderm that forms the lining of the digestive tube and the respiratory system. The chapter describes the similarity of homologous structures in different species, which is the result of sharing a common ancestral structure. It traces the evolutionary history of life on Earth that reveals adaptations that occurred in the developmental processes governing plant and animal traits.
Stem Cells
Authors: Barresi Michael J. F. , Gilbert Scott F.
Published: September 2023

This chapter discusses the stem cell, which maintains the ability to divide and produce a copy of itself and generate progenitor cells capable of maturing into different cell types. It explains how the niche employs a variety of mechanisms of cell-to-cell communication to regulate the quiescent, proliferative, and differentiative states of the resident stem cell. It also explores columnar cells located at the base of the intestinal crypt that serve as clonogenic stem cells for the gut epithelium, which generates transit-amplifying epithelial cells that slowly differentiate as they are pushed farther up the villus. The chapter looks at mesenchymal stem cells that are found in a variety of tissues, including connective tissue, muscle, cornea, dental pulp, and bone. It covers pluripotent stem cells that can be used in regenerative medicine to rebuild tissues and to make structures called organoids.
The Web of Life
Authors: Bowman William D. , Hacker Sally D.
Published: September 2023

Key Concepts

CONCEPT 1.1 Events in the natural world are interconnected.

CONCEPT 1.2 Ecology is the scientific study of interactions between organisms and their environment.

CONCEPT 1.3 Ecologists evaluate competing hypotheses about natural systems with observations, experiments, and models.
The Physical Environment
Authors: Bowman William D. , Hacker Sally D.
Published: September 2023

Key Concepts

CONCEPT 2.1 Climate is the most fundamental component of the physical environment.

CONCEPT 2.2 Winds and ocean currents result from differences in solar radiation across Earth’s surface.

CONCEPT 2.3 Large-scale atmospheric and oceanic circulation patterns establish global patterns of temperature and precipitation....

CONCEPT...
Coping with Environmental Variation: Temperature and Water
Authors: Bowman William D. , Hacker Sally D.
Published: September 2023

Key Concepts

CONCEPT 4.1 Each species has a range of environmental tolerances that determines its potential geographic distribution.

CONCEPT 4.2 The temperature of an organism is determined by exchanges of energy with the external environment.

CONCEPT 4.3 The water balance of an organism is...
Population Dynamics
Authors: Bowman William D. , Hacker Sally D.
Published: September 2023

Key Concepts

CONCEPT 10.1 Populations are dynamic entities that vary in size over time.

CONCEPT 10.2 The risk of extinction increases in populations that fluctuate in size and/or are small.
Population Growth and Regulation
Authors: Bowman William D. , Hacker Sally D.
Published: September 2023

Key Concepts

CONCEPT 11.1 Populations can grow exponentially when conditions are favorable, but exponential growth cannot continue indefinitely.

CONCEPT 11.2 Population size is determined by a combination of density-dependent and density-independent factors.

CONCEPT 11.3 The logistic equation incorporates limits to growth and shows how...
Predation
Authors: Bowman William D. , Hacker Sally D.
Published: September 2023

Key Concepts

CONCEPT 12.1 Most carnivores have broad diets, whereas a majority of herbivores have relatively narrow diets.

CONCEPT 12.2 Predation results in a wide range of capture and avoidance mechanisms.

CONCEPT 12.3 Predator populations can cycle with their prey populations.

CONCEPT 12.4 Predation...
Mutualism and Commensalism
Authors: Bowman William D. , Hacker Sally D.
Published: September 2023

Key Concepts

CONCEPT 15.1 In positive interactions, no species is harmed, and the benefits are greater than the costs for at least one species.

CONCEPT 15.2 Each partner in a mutualistic interaction acts in ways that serve its own ecological and evolutionary interests.

CONCEPT 15.3...
Change in Communities
Authors: Bowman William D. , Hacker Sally D.
Published: September 2023

Key Concepts

CONCEPT 17.1 Agents of change act on communities across all temporal and spatial scales.

CONCEPT 17.2 Succession is the process of change in species composition over time as a result of abiotic and biotic agents of change.

CONCEPT 17.3 Experimental work on...
Species Diversity in Communities
Authors: Bowman William D. , Hacker Sally D.
Published: September 2023

Key Concepts

CONCEPT 19.1 Species diversity differs among communities as a consequence of regional species pools, abiotic conditions, and species interactions.

CONCEPT 19.2 Resource partitioning is theorized to reduce competition and increase species diversity.

CONCEPT 19.3 Processes such as disturbance, stress, predation, and positive...
Energy Flow and Food Webs
Authors: Bowman William D. , Hacker Sally D.
Published: September 2023

Key Concepts

CONCEPT 21.1 Trophic levels describe the feeding positions of groups of organisms in ecosystems.

CONCEPT 21.2 The amount of energy transferred from one trophic level to the next depends on food quality and on consumer abundance and physiology.

CONCEPT 21.3 Changes in...
The Heavier d-Block Metals
Authors: Housecroft Catherine E.
Published: September 2023

The Heavier d-Block Metals addresses the chemistry of the second- and third-row d-block metals. Chapter 1 looks at the metals and summarizes occurrence, physical properties, and uses. Chapter 2 considers periodic trends in properties. Chapter 3 considers aqueous solution chemistry, species present (with comparisons of the first-row metal ions), and redox properties. Chapter 4 surveys structure. Chapter 5 looks at electronic spectra and magnetic properties, making comparisons with the first row the main objective of the chapter. Chapter 6 considers metal-metal bonding, and the classes of compound that contain triple and quadruple bonds, and the role of bridging ligands is introduced. Chapter 7 looks at selected clusters with a pi donor ligands (e.g. metal halo species) in which metal-metal bonding is important. Chapter 8 introduces the area of polyoxometalates, closing with a short discussion of the wide range of applications.
Chemistry of the First-row Transition Metals
Authors: McCleverty Jon
Published: September 2023

Chemistry of the First Row Transition Metals introduces this field of chemistry. The reactivity and structural properties of first-row transition metals and their compounds depend on the electronic configuration of the d electrons of the metal. The book describes the most significant structures, reactions, and other important properties of co-ordination, organometallic and solid-state compounds, and also sketches the role of first-row transition metals in biology.
Metals in solution
Authors: McCleverty Jon
Published: September 2023

This chapter examines the occurrence of the dissociation of ligands, which may have a reaction between the ligands or the metal and the solvent and aggregation in order to give di- or oligo-nuclear species. It describes the thermodynamic stability of a complex that can be revealed by an equilibrium constant and relates its concentration to the concentration of all other related species when the system has reached equilibrium. It also analyses the kinetic stability of a species that refers to the speed at which transformation leads to the attainment of equilibrium. The chapter reviews the metal complexes of chelating ligands that have significantly higher stability than their analogues containing only mono- or uni-dentate ligands. It traces the origin of the chelate effect that lies in enthalpic and entropic factors.
Compounds in higher oxidation states
Authors: McCleverty Jon
Published: September 2023

This chapter deals with oxo, nitride, imido, and amido species, some organometallic species, reactions of coordinated ligands, and metal complexes where the ligand is oxidized. It discusses the highest oxidation states from Ti to Mn which can only be stabilized by oxo, fluoro or chloro ligands. It also explains how the molecular oxygen reacts reversibly with some metal complexes and is involved in the transport and storage of dioxygen by haemoglobin and other metalloproteins. The chapter describes alkoxides which are hydrolyzed but are thermally stable, distillable liquids or volatile solids. It talks about important organometallic compounds of the first-row transition metals. These are known in oxidation states III, IV, and V, and titanium organometallics and are extremely important in polymerization catalysis. It highlights oxidation or disproportionation that accompanies some metals in the formation of the alkyl compound.
Acid-labile protecting groups
Authors: Robertson Jeremy
Published: September 2023

This chapter discusses acid-labile protecting groups. In the protected forms of potentially nucleophilic functional groupsalcohols, amines, and thiolsthe original heteroatom is usually present and capable of reacting with electrophiles unless steric encumbrance or conjugation is completely effective. Whether or not this leads to deprotection depends on the groups attached to the heteroatom. Reversible protonation or activation with a Lewis acid polarises the electrons in the attached bonds leading to electron deficiency at adjacent centres. If one of the attached groups is capable of supporting a full positive charge then rapid cleavage is likely to follow. This behaviour forms the basis of a large range of acid-labile protecting groups that cleave by forming a stabilised cationic intermediate on addition of either a protic or Lewis acid reagent. The chapter then considers SN1-like deprotection, nucleophile-assisted deprotection, and deprotection following activation by alkylation.
Nucleophile/base-labile protecting groups
Authors: Robertson Jeremy
Published: September 2023

This chapter examines nucleophile/base-labile protecting groups. The majority of the functional groups described in this book are based on heteroatoms that, by virtue of higher electronegativity or more diffuse orbitals, can support a negative charge more effectively than carbon. Consequently, some protecting groups can be cleaved by expulsion of the functional group as an anion either by elimination or by nucleophilic substitution. Whether or not activation is necessary depends upon the leaving group ability of the protected functional group, the nucleophilicity of the attacking species, the solvent, and the steric availability at the electrophilic site. The chapter then looks at protecting group cleavage by SN2 chemistry and by nucleophilic addition, as well as deprotection by β-elimination. It also considers allylic protecting groups.
Introduction
Authors: McCash Elaine M.
Published: September 2023

This introductory chapter provides an overview of solid surfaces, which are of particular importance in everyday life. Some of the most important areas in which they play a vital role include heterogeneous catalysis and corrosion. The behaviour of surfaces is also crucial in the fields of electrochemistry, photography, colloids, optics, data storage, and, increasingly, in biological applications such as the use of membranes and biosensors. Thus, the study of surfaces and their behaviour requires a wide range of chemical knowledge and understanding. This books assumes a knowledge of the basic principles of physical chemistry, especially kinetics, dynamics, and thermodynamics. The chapter then looks at the single crystal surface, before outlining the techniques for studying surfaces.
Foundations of Physics for Chemists
Authors: Ritchie G.A.D. , Sivia D.S.
Published: September 2023

Foundations of Physics for Chemists presents the fundamental physics required for a full understanding of a diverse range of chemical phenomena and techniques such as diffraction, reaction rates, and nuclear magnetic resonance. The text begins with a discussion of classical and wave mechanics, which allows quantum mechanics to be introduced at an early stage. The ideas presented in these early chapters are subsequently developed to deal with the traditional physics topics of kinetic theory, electrostatics, magnetism, and optics. However, the text maintains a distinct chemical perspective by focusing on relevant chemical examples rather than hypothetical examples.
An introduction to the uses of power ultrasound in chemistry
Authors: Mason Timothy J.
Published: September 2023

This chapter provides an overview of sonochemistry, a term primarily used to describe the effect of ultrasonic sound waves on chemical reactions, but also applied to processes involving power ultrasound. It begins by assessing the power of sound and the importance of power ultrasound in industry. It has been recognised for many years that power ultrasound has great potential for use in a wide variety of processes in the chemical and allied industries. Two of these applications have provided the direct antecedents of the types of equipment now commonly used for sonochemistry: ultrasonic welders and cleaning baths. The chapter then looks at cavitation — the origin of sonochemical effects — and the parameters which affect sonochemistry. It also considers the types of chemical systems affected by power ultrasound; the generation of ultrasound; the cavitation threshold; ultrasonic power measurement; and the types of sonochemistry equipment.
General principles and historical aspects
Authors: Walton David J. , Lorimer J. Phillip
Published: September 2023

This chapter examines chain polymerization. This class of polymer accounts for a large proportion of the synthetic polymer industry and includes the large-tonnage materials such as polyethene, polystyrene, polyvinylchloride (PVC), and acrylics. The reaction mechanisms, which affect the build-up of polymer molar mass (RMM), and other factors are different for alkene polymers and polyurethanes. The alkene systems involve chain reaction mechanisms and the class of materials is called chain polymers. Chain polymers can be prepared in one of three ways. In free-radical polymerization, the alkene double bond opens homolytically. In cationic polymerization, an electron-deficient species removes both electrons from the electron-rich double bond. In anionic polymerization, a species more electron-rich than the double bond increases electron density of the π bonds such that heterolytic fission gives a negatively charged propagating chain end-group. The chapter then considers commercial chain polymer syntheses; the synthesis of monomers; and the properties of chain-growth polymers.
Conclusions and further reading
Authors: Walton David J. , Lorimer J. Phillip
Published: September 2023

This concluding chapter explains how polymers provide a convenient opportunity to study industrial aspects of chemical science. Indeed, considerations of economics, availability of feedstocks, use of specialized catalytic reactions, and similar matters are found throughout the chemical industry. However, polymers provide particularly instructive examples. It is an appropriate time to review polymers since there are many new aspects and applications in prospect. This is a very wide subject to cover and readers are encouraged to investigate more specialized bibliography for areas of interest. The chapter then offers some recommendations of reference books on all aspects of polymer science and technology, including series of volumes extensively filled with data.
Computers in Chemistry
Authors: Pete Biggs
Published: September 2023

Computers in Chemistry introduces the use of computer technology in the chemical sciences. Computers have become an integral part of chemistry. Virtually all modern scientific instrumentation contains some form of computer and, indeed, the operation of many instruments has become so complex that it is impossible without some degree of computer control. It is very important for the modern student of chemistry to have at least a basic knowledge of computers, and the deeper that knowledge is, the better use will be made of the techniques available.
Computational chemistry
Authors: Pete Biggs
Published: September 2023

This chapter focuses on computational chemistry, which is explained as using computers to calculate chemistry, such as molecular properties, reaction rate, fundamental properties of a system, or theoretical models as basis for calculating other properties. It stresses how computational chemistry has become an important branch of chemistry as the power of computers increases with faster and more complex calculations. The chapter also discusses program packages which have been developed to allow non-programmers to perform complex calculations. The chapter describes two different forms of packages: ones that are designed for a particular application and others which are more general in nature. It discusses the Gaussian commercial package, which is used to calculate molecular parameters from a theoretical basis, as an example of the former.
Phase equilibria and crystallization techniques
Authors: Davey Roger J. , Garside John
Published: September 2023

This chapter begins by looking at the use of the information available in phase diagrams to define the nature of the crystalline phase that will appear under a given set of conditions of temperature, pressure, and composition. The phase rule tells us under which conditions certain systems can be in equilibrium. The chapter then examines the nature of the driving force for crystallization processes and outlines some typical techniques used for preparing crystalline materials, including suspension crystallization and the solidification of melts. Crystallization is a kinetic process and, traditionally, chemists are familiar with the use of reagent concentration to describe the driving force for the chemical rate process. However, in the case of crystallization, the concentration range over which the process can occur is limited by the equilibrium composition of the system corresponding to the conditions chosen.
Identical particles
Authors: Bowley Roger , Sánchez Mariana
Published: September 2023

This chapter introduces the partition function that involves a sum over independent quantum states of the N-particle system. It outlines the problem of distinguishability, that is, how to distinguish one electron from another when they are replicas of each other and are all the same. It also emphasizes that electrons have no feature or label based on which they can be told apart, and they repeat the same attributes endlessly. The chapter explains that identical particles lead to complications in the quantum mechanical description of the microscopic state of the system as there are no observable changes in the system when any two particles are exchanged. It analyses the uncertainty principle, wherein the position of a particle cannot be accurately specified at each stage, nor can the precise trajectory of a particle be followed.
Fermi and Bose particles
Authors: Bowley Roger , Sánchez Mariana
Published: September 2023

This chapter reviews the techniques of the grand canonical ensemble to give an exact treatment for both Bose and Fermi particles. It looks at the results of Maxwell-Boltzmann statistics for the average number of particles in sufficiently high temperatures and in a single-particle state for both fermions and bosons. It also examines the exclusion principle in Fermi particles, which means that there cannot be two particles in the same single-particle state, while there is no such restriction for Bose particles. The chapter clarifies that the resulting formulae for the average number of particles in a single-particle state are different at low temperatures. It describes Fermi particles at low temperatures that have a large kinetic energy, an energy which can be much larger than the interaction between particles.
Titrations
Authors: de Levie Robert
Published: September 2023

This chapter evaluates titrations. The primary purpose of titrations is to measure an unknown amount of a substance in a sample through a chemical reaction with a known amount of a suitable reagent, in such a way that we can observe when an equivalent amount of reagent has been added to the sample. From a knowledge of that equivalence point, we can then determine the unknown amount. When the equivalence point is reached after a reaction of a volume of titrant of concentration, the two amounts are related to each other through the appropriate stoichiometric factor. While this relation only yields the unknown concentration, a more complete analysis shows that a titration can provide additional information about the sample. In the case of acid-base titrations, such additional information consists of the acid dissociation constants of the sample. The chapter then looks at titration curves and titration errors.
Electroanalysis
Authors: Brett Christopher M. A. , Brett Ana Maria Oliveira
Published: September 2023

Electroanalysis introduces the techniques and areas of application of modern electroanalysis, which has a particularly important role within current environmental concerns, both in the laboratory and in the field. The text begins by describing the basic principles of the necessary electrochemistry and then moves on to electrochemical sensors and their mode of functioning. Potentiometric sensors are described, including many types of selective electrode. Following this, amperometric and voltametric sensors are discussed together with the various instrumentation and electrode modification strategies to enhance sensitivity and selectivity. A final chapter shows the range of applications of modern electroanalysis, with particular emphasis on trace species, and indicates future trends.
Oxidation of carbon-carbon double and triple bonds
Authors: Donohoe Timothy J.
Published: September 2023

This chapter examines the oxidation of carbon–carbon double and triple bonds. The oxidation of carbon–carbon π-bonds can yield several useful functional groups. Many oxidising agents have been developed for this purpose. In fact, one of the main advantages of oxidising alkenes is that the product distribution can be controlled, and a particular functional group formed, simply by the choice of oxidant. The chapter begins by looking at the oxidation of alkenes to form epoxides. Epoxides are the cyclic ethers that may be formed from the reaction of an alkene with an oxidising agent. They are electrophiles and they react with nucleophiles such as water. The chapter then considers the addition to alkenes via epi-ions; the oxidation of alkenes to syn diols; the formation of ketones from alkenes and the Wacker process; and the oxidation of alkynes to 1,2-diketones.
Oxidative cleavage reactions
Authors: Donohoe Timothy J.
Published: September 2023

This chapter focuses on reactions which lead to the cleavage of carbon–carbon single (and multiple) bonds and the introduction of new bonds between carbon and an electronegative element, such as oxygen. It also considers the similar process which leads to the cleavage of bonds between carbon and other electropositive elements such as boron or silicon. The chapter begins by looking at the oxidative cleavage of carbon–carbon double bonds. Clipping an alkene to furnish two carbonyl compounds is most readily carried out with ozone (O3): the four substituents that were attached to the alkene end up as substituents on the two new carbonyl containing compounds. The chapter then studies the oxidative cleavage of carbon–carbon sigma bonds; of carbon–boron and carbon–silicon bonds; and of carbon–halogen bonds.
Reduction of heteroatoms attached to carbon
Authors: Donohoe Timothy J.
Published: September 2023

This chapter assesses the reduction of heteroatoms attached to carbon. It begins by looking at the reduction of nitrogen-containing functional groups. Aromatic nitro compounds (such as nitrobenzene) play a vital role in the synthesis of substituted arenes partly because they direct electrophilic aromatic substitution so powerfully. In general terms, both aromatic and aliphatic nitro groups are easy to reduce, often without affecting other functionality. The chapter then considers the reduction of phosphorus–oxygen bonds. Reduction of a phosphorus–oxygen double bond is not a particularly common reaction, and there is not a great deal of work in this area. As such, the chapter turns to reduction of sulfur- and selenium-containing functional groups.
Reduction of carbon–heteroatom double and triple bonds
Authors: Donohoe Timothy J.
Published: September 2023

This chapter explores the reduction of carbon–heteroatom double and triple bonds. There are many functional groups based on multiple bonds between carbon and either oxygen or nitrogen. The chapter demonstrates some of the corresponding reduction reactions of these functional groups. It begins by looking at the reduction of carbon–nitrogen π-bonds. Nitriles contain a strong triple bond between carbon and nitrogen. In terms of reactivity, nitriles are susceptible to nucleophilic attack and therefore reduction of these groups is easily effected by 'hydride' reducing agents. The chapter then considers the reduction of carbon–oxygen π-bonds. The reduction of aldehydes to primary alcohols and ketones to secondary alcohols is normally easy to accomplish using sodium borohydride or lithium aluminium hydride.
Metallated saturated hydrocarbons
Authors: Jenkins Paul R.
Published: September 2023

This chapter reviews the most important method for the preparation of the reagents, which is the reaction of a metal with an alkyl halide. It analyzes how a reagent is produced as a complex with lithium bromide in ether solution, noting that the butyllithium solution is available commercially and is not normally prepared. It also considers butyllithium solutions as one of the most significant events in modern organic synthesis, as the actual structure butyllithium is more complicated than Bu-reagent. The chapter looks at the extensive studies based on X-ray crystal structures and nuclear magnetic resonance experiments which indicate that what is actually present in a solution of methyl- or butyllithium is not monomeric species. It discusses the metalated alkanes which exist as clearly defined aggregates in which the metal atoms make up a regular framework with each carbanionic carbon atom.
Metallated aromatic compounds
Authors: Jenkins Paul R.
Published: September 2023

This chapter discusses the generation of metalated aromatic compounds from aromatic halides, which is considered an efficient route for reagents. It mentions phenyl Grignard and phenyllithium prepared from bromobenzene and the metal in ether, including the regiospecific production of aryllithium compounds that occurs when aromatic halides react with butyllithium. It also examines bromide when it is converted into a lithium reagent. The chapter examines reactions of simple aryl Grignard and lithium compounds that are the same as their alkyl counterparts. The chapter covers topics that are essential to aromatic compounds. These are explained with illustrations of the reactions of the metalated species. It cites substituents that exert a profound effect on the reaction of a benzene ring with butyllithium in both deprotonation and lithium-halogen exchange reactions.
Nucleophilic aromatic substitution
Authors: Sainsbury Malcolm
Published: September 2023

This chapter focuses on nucleophilic aromatic substitution. In the case of alkyl halides, two main modes of nucleophilic substitution are possible. For those halides which can dissociate to give a stable carbocation this is the rate determining step. The slow step only depends upon the alkyl halide and the overall reaction is called a SN1 process. Simple primary carbocations are too unstable to be formed in this way, and here the nucleophile approaches the alkyl halide so that the angle between it and the departing halogen is 180°. The reaction is thus bimolecular and the rate depends on the concentrations of both the nucleophile and the alkyl halide: it is designated a SN2 process. The chapter then considers aryne formation.
Aromatic compounds
Authors: Sainsbury Malcolm
Published: September 2023

This chapter assesses aromatic compounds. Alkenylbenzenes are normally synthesized through the dehydration of arylalkanols, or by the dehydrohalogenation of arylalkyl halides. The best known alkenylarene, ethenylbenzene (styrene), is obtained commercially from benzene in two steps: first, alkylation with ethene in the presence of an acid or a Lewis acid, and second, dehydrogenation of the product, ethylbenzene, by heating over a catalyst at 600°C. Styrene undergoes radical initiated polymerization with itself, to form polystyrene, or with other molecules to form copolymers; both processes have important commercial applications. The chapter then looks at aromatic halides; aromatic alcohols; aromatic carbonyl compounds; and aromatic acids, esters, and amides. It also considers aromatic sulfonic acids, nitro compounds and reduction products, aromatic amines, and phenols.
Surfaces
Authors: Attard Gary , Barnes Colin
Published: September 2023

This book provides an introduction to the subject of surfaces. The first chapter concerns basic thermodynamic material used to understand the properties of surfaces including; surface tension, Gibbs adsorption, surface pressure and surface phase equilibria, surfactants and micelles, wetting, detergency, and contact angle. The second chapter concentrates on gas adsorption at solid surfaces and covers topics including adsorption, Langmuir isotherms, heats of adsorption, BET isotherms, physisorption, chemisorption, precursor adsorption kinetics, well-defined surfaces, UHV, surface sensitivity and selectivity, surface diffusion and electrons interacting with matter. The final chapter contains a series of worked examples and problems, bringing together the various strands developed in Chapters 1-3 in order to elucidate surface phenomena.
Coordination Chemistry of Macrocyclic Compounds
Authors: Constable Edwin C.
Published: September 2023

Coordination Chemistry of Macrocyclic Compounds describes the coordination chemistry of macrocyclic ligands. Common types of ligands are introduced and strategies for the synthesis of the free ligands and their metal complexes are discussed. The unique thermodynamic and kinetic properties of macrocyclic complexes are discussed and applications of the ligands presented.
Artificial neural networks
Authors: M Hugh
Published: September 2023

This chapter covers artificial neural networks, which are an example of a connectionist model with many logical units that are connected in a network. It reviews the way in which the brain is believed to function, as the design of the artificial neural networks is inspired by the structure of that organ. It also explains that the neuron is the fundamental processing unit in a typical human brain. The chapter talks about the behaviour of the neuron as a threshold device that has a step-like shape known as a step function or Heaviside function. The chapter points out the crucial feature of the behaviour of the brain, which is that it does not need to be taught how to learn. It observes that artificial neural network programs are multi-purpose as they can solve problems by using spectral interpretation, propositional logic, image analysis, or fingerprint interpretation.
Concluding remarks
Authors: Guy H. Grant , W. Graham Richards
Published: September 2023

The object of the preceding chapters was to provide an introduction to many of the methods currently used by practising computational chemists; in no way was it intended as a ‘how to do it’ manual. Although the emphasis has been on computer modelling of biological...
Catalysed substitution reactions
Authors: Henderson Richard A.
Published: September 2023

This chapter shows how the rates of substitution reactions at a variety of metal sites can be accelerated by base, acid, or electron transfer. It mentions Werner-type complexes of cobalt(III), chromium(III), ruthenium(III), rhodium (III), and iridium(III), which are the most extensively studied system showing base catalysis. What generated interest in these reactions was the apparent anomaly in the reaction of hydroxide that appears to be an exception to the general rule that the rate of substitution at cobalt(III) complexes show the characteristics of a dissociative mechanism. In addition, reactions with hydroxide were faster than the corresponding rates of solvolysis typically studied in acidic solution. The chapter explains that the main feature of this mechanism is the deprotonation of an anime ligand which generates the conjugate base of the complex.
Introduction to Organic Spectroscopy
Authors: Harwood Laurence M. , Claridge Timothy D.W.
Published: September 2023

Introduction to Organic Spectroscopy aims to provide an understanding of spectroscopic techniques in the analysis of chemical structures. The book starts with an introduction to the theory. It then looks at ultra violet-visible spectroscopy. Next it considers infrared spectroscopy. Then it considers nuclear magnetic resonance spectroscopy in basic terms and then in more detail. The last chapter is about mass spectrometry.
Organic Synthesis
Authors: Willis Christine L. , Wills Martin
Published: September 2023

Organic Synthesis uses a wide range of examples to teach students of chemistry how to adopt a logical and versatile approach to the design of synthetic routes. The ability to design effective syntheses is an important skill for organic chemists. The concept of retrosynthetic analysis—a means for identifying simple starting materials for a synthesis—is first introduced with emphasis on the importance of bond polarity and functional group interconversions. The next section describes how an effective route to a target molecule containing more than one functional group can be elucidated, and gives useful strategies to adopt when designing syntheses. Later chapters review methods for the control of chemo-, regio-, and stereoselectivity, and include a discussion of protecting groups. Finally, four syntheses of the pyrrolidine alkaloids are compared and contrasted using the principles described in the book.
Fundamental ideas
Authors: Wayne Richard R
Published: September 2023

This chapter provides a background on experiments in chemistry that explain the nature of interactions that lead to chemical change. It identifies chemical species of great complexity present at minute concentrations, which depended on the development of sensitive and precise instrumentation. It discusses the black-box approach to chemical instrumentation which is considered effective so long as nothing more is asked than the performance that the manufacturers intended. It also introduces building blocks and devices used in industry research. The chapter gives a basic understanding of how instrumentation works, and knowledge that devises novel ways of using existing instrumentation and new tools by which chemistry may be studied. It points out how scientific instruments encode the information of interest in some form of electrical signal to be manipulated and decoded into a useful form.
Simple measuring instruments
Authors: Wayne Richard R
Published: September 2023

This chapter reviews the objective of instrumentation, which is to convert some phenomenon of chemical interest to an electrical signal, manipulate it, and turn the processed result into something useable by the experimenter. It examines output and input interfaces that provide transducers as they convert a non-electrical phenomenon to or from an electrical one. It also talks about modern instrumentation which uses a computer and its associated memory wherein the interface with the investigator is the screen display, printed results, or similar output. It also discusses the final link or output transducer, which are familiar electrical measuring instruments, such as meters, pen coders, and oscilloscopes. The chapter reviews the use of hearing in the detection of an audiofrequency a.c. signal. It considers the types of electrical signal that are converted for interpretation by the experimenter.
Input transducers
Authors: Wayne Richard R
Published: September 2023

This chapter examines important ways in which non-electrical variables which are measured in experiments may be converted into electrical phenomena for the processing and conditioning of the signals. It focuses on the measurement of the most basic physical quantities, such as spatial position, temperature, or light intensity, and explains how non-electrical phenomenon may be converted to another non-electrical phenomenon that is interfaced to an electrical transducer. It also cites the measurement of pressure as an example, emphasizing that the pressure of a gas might be used to distort a capsule in a type of barometer. The chapter discusses electrochemical measurements wherein the electrical signal is produced directly by the chemical phenomenon of interest. It talks about the electrode or similar device which is used as the input transducer that probes the chemical system.
Noise and its reduction
Authors: Wayne Richard R
Published: September 2023

This chapter highlights the term noise, which means there are voltages or currents present which are not related to the quantity of being investigated in terms of electrical systems. It explains how the noise detracts from the information which can be gathered from a material to which the hearer is listening. It also discusses the signal-to-noise (S/N) ratio, which is the measure of the relative magnitudes of the wanted signal and the unwanted noise. It emphasizes that the smaller the S/N ratio, the more difficult it is to make the required measurement. The chapter outlines the sources of noise and extent to which the noise may be reduced. It illustrates methods for making the best of the initial S/N ratio and enhancing the precision of the measurements.
Energy Levels in Atoms and Molecules
Authors: Richards W.G. , Scott P.R.
Published: September 2023

Energy Levels in Atoms and Molecules provides an introduction to the energy levels present in atoms and molecules. It presents useful information within the field of electronic structure and quantized mechanics and spectroscopy. The first chapter concentrates specifically on atoms. The next chapters covers diatomic molecules. The chapter that follows that is about polyatomic molecules. Next, there is a chapter that explains energy levels at nuclear magnetic resonance (NMR). The text then concludes.
Diatomic molecules
Authors: Richards W.G. , Scott P.R.
Published: September 2023

This chapter talks about orbital approximation, which carries over directly to molecules and is useful in understanding the electronic structure of atoms. It points out that the wave function for a molecule is expressed approximately as a product of one-electron wave functions and analyses aspects of the atomic notation which carry over to the molecular situation. It also mentions the Pauli principle. This applies to electrons in molecules and atoms, which in its simplest form prevents any pair of electrons in a molecule having identical quantum numbers. The chapter cites the added complicated possessed by molecules wherein the energy of a molecule depends on the relative position of its nuclei. It reviews the Born-Oppenheimer approximation. This treats nuclear and electronic motion as independent.
Enamines, enol ethers, and enolates
Authors: Ward Robert S.
Published: September 2023

This chapter deals with enamines, enol ethers, and enolates. Enamines are nucleophilic reagents that undergo alkylation, acylation, and conjugation addition reactions. The chapter elaborates how enamines afford an indirect route for preparing substituted carbonyl compounds, noting that they are prepared from aldehydes and ketones and their salts are hydrolysed by aqueous acid to regenerate the carbonyl group. It explains that for aldehydes and ketones, the enol tautomer is less stable than the keto form and only very little enol is present. The chapter highlights that the enol tautomer predominates for some carbonyl compounds due to extra stabilization afforded by intramolecular hydrogen bonding. It explains that the interconversion of the keto and enol forms is catalysed by acid or base.
Structure and Reactivity in Organic Chemistry
Authors: Maskill Howard
Published: September 2023

Structure and Reactivity in Organic Chemistry starts with a consideration of molecular vibrations and intermolecular interactions, and introduces the use of potential energy profiles and reaction maps to describe organic chemical transformations. The relationship between kinetics and organic reaction mechanisms is then explored with special emphasis on the interpretation of activation parameters. The relationship between molecular structure and chemical reactivity, i.e. correlation analysis, is then covered, followed by a chapter on catalysis of organic chemical reactions in solution by small molecules. The treatment of catalysis explores how the molecular structure of compounds determines their reactivity either as substrates or as catalysts. The final chapter is devoted to isotope effects in mechanistic organic chemistry, concentrating on deuterium kinetic isotope effects.
Thromboxane antagonists
Authors: Lee Stan , Robinson Graham
Published: September 2023

This chapter defines thromboxane A2 as a naturally occurring substance that has the undesirable effects of bronchoconstriction, aggregation of the blood platelets, and constriction of the blood vessels whenever it is released in the body. The inhibition of the effects of thromboxane A2 could lead to a potential treatment for circulatory or respiratory disorders. The chapter discusses a series of thromboxane antagonists that have been developed in ICI. These have similar structures to thromboxane A2 and are therefore able to block the relevant receptor site in the body. The chapter highlights that the synthetic challenge for a compound to be viable as a pharmaceutical agent is achieving stereochemical control using methods that can be operated on a larger scale. The chapter covers different compounds that were synthesized in small quantities using a route that enabled the synthesis of many analogues for biological evaluation.
H2 blockers
Authors: Lee Stan , Robinson Graham
Published: September 2023

This chapter focuses on H2 blockers, which are a class of pharmaceutical compounds that block the H2 receptors in the stomach lining and lower the secretion of HCI. It explains that excessive activity of the secretory glands leads to strongly acidic conditions and a tendency towards the formation of stomach ulcers. It also highlights how H2 blockers can help heal ulcers naturally without the necessity for surgery in the case of mild conditions. They can also minimize their recurrence under more alkaline conditions. The chapter illustrates the research process for an H2-blocking compound developed by ICI. It covers how the compound was synthesized from three fragments, the manufacturing difficulties, and how these had to be addressed by the manufacturing route.