bluuebunny/crossref_metadata_2025 huggingface dataset:
Metal complexes in solution
Authors: Howard Alan G.
Published: September 2023

This chapter investigates metal complexes in solution. With modern technology, it is possible to find almost every element of the periodic table in a sample of natural water. Which metals are present in significant quantities will, in the case of groundwaters, streams, rivers, and lakes, reflect the geology of the catchment area and the past history of the water. Some of the major factors influencing the concentrations of trace metals in oceanic waters, away from coastal influences, are inputs from bottom sediments and hydrothermal activity; deposition of material from the atmosphere together with removal by chemical adsorption onto surfaces; and precipitation and accumulation by marine organisms. The chapter then describes some of the chemistry underlying the formation of metal complexes and outlines some of the techniques which can be employed to provide an insight into the chemical species which might be present in natural and polluted waters.
Classical mechanics
Authors: Ritchie G.A.D. , Sivia D.S.
Published: September 2023

This chapter begins with a discussion of Isaac Newton's work on forces and motion—in other words, classical or Newtonian mechanics. It explains the dependence on the orientation of the force that determines that it is a vector quantity specified by both a magnitude and direction. The chapter also explains how the statement of Newton's first law of motion can be made more succinct by rephrasing it in terms of a uniform velocity. The chapter paraphrases the first law of motion by saying that a force is required to change an object's velocity. It discusses the central role of statics in working out the strength of the materials needed to prevent a bridge from collapsing or the frictional roughness of a surface required to stop a ladder from slipping.
Quantum mechanics
Authors: Ritchie G.A.D. , Sivia D.S.
Published: September 2023

This chapter considers the birth of quantum theory, which marks another important event in the modernization of physics and chemistry as it facilitates explaining phenomena at an atomic scale. In a first step, the chapter provides an overview of several phenomena that have long been a source of controversies among scientists, namely the nature of light, the nature of matter, and the fact that the colour of solids heated in a furnace is determined by temperature rather than the make-up of the material. None of these could be adequately explained by classical mechanics. The chapter then discusses Planck’s quantum hypothesis, which provided a major breakthrough in this regard. Finally, it traces the formalization of quantum mechanics, which was required to enable its application to a wider range of problems.
Appendix
Authors: Ritchie G.A.D. , Sivia D.S.
Published: September 2023

Solutions to problems

1 Classical mechanics

1.1

(a) v
1 = –3/4u

v
2 = 1/4u

(b) Fraction of original KE lost = 1/8

1.2

Equatorial gravitational field strength = –9.841m s–2

Polar gravitational field strength = –9.906 m s–2...
Sonochemistry
Authors: Mason Timothy J.
Published: September 2023

Sonochemistry starts off asking the questions: what is sonochemistry and why is it important? It has been recognised for many years that power ultrasound has great potential for uses in a wide variety of processes in the chemical and allied industries. Reported applications include cleaning, sterilization, flotation, drying, degassing, defoaming, soldering, plastic welding, drilling, filtration, homogenization, emulsification, dissolution, deaggregation of powder, biological cell disruption, extraction, crystallization and, more recently, as a stimulus for chemical reactions. With the increasing use of power ultrasound in chemistry comes the need for specialist text books covering this emerging discipline. The text also asks: what systems are affected by sonochemistry? It looks at the major applications of this technique, the types of ultrasonic equipment that are available, how the different types of equipment compare, and how the equipment is best configured for chemical applications. Finally, it asks: what parameters can be changed to optimize sonochemical results and what equipment is available for the scale-up of sonochemistry?
Flow systems and scale-up in sonochemistry
Authors: Mason Timothy J.
Published: September 2023

This chapter provides an overview of the available systems that can be used to carry out sonochemical transformations on a scale larger than that used in the research laboratory. There are essentially two types of large-scale chemical plant: batch and flow type. Sometimes, the flow system will form a part of batch processing as a loop attached to the main vat. The first decision to be made when considering how a sonochemical reaction should be scaled up is whether that reaction is in fact truly sonochemical or simply the result of an ultrasonically induced mechanical effect. The chapter then looks at sonochemical efficiency; large-scale ultrasonic systems, including batch reactors, flow systems, and the vibrating tray; and low-frequency high-power processing systems. It also considers the future of sonochemistry in industry.
General principles and historical aspects
Authors: Walton David J. , Lorimer J. Phillip
Published: September 2023

This chapter provides an overview of polymers, which are formed by linking large numbers of small molecules together. Polymers are now ubiquitous in daily life. Not only have polymers found a wide use in structural and textile materials, polymer substitutes have also found a wide application in medicine. Moreover, synthetic polymers have had a sizeable impact in the field of fibres, plastics, and rubbers (elastomers). While the majority of polymers are synthetic polymers, there are natural polymers such as proteins, natural rubber, and cellulose, each of which could be fitted into a similar category. It was as a result of early attempts to modify these natural materials that the important understanding of polymer behaviour arose. The chapter then presents the general principles of polymerization; the statistical nature of polymer chains; and the general principles of industrial polymer synthesis.
Polymer properties and characterization
Authors: Walton David J. , Lorimer J. Phillip
Published: September 2023

This chapter discusses the properties and characterization of polymers. The techniques most commonly used to determine polymer molar mass include end-group analysis, osmometry, light scattering, ultracentrifugation, sedimentation, viscometry, and chromatography. However, most of these involve rather lengthy procedures and in practice molar masses are obtained from high performance gel permeation chromatography (HPGPC) or viscosity measurements. It is important to recognize that the fundamental measurements of molar mass must be performed on dilute solutions so that intermolecular interactions can be ignored. The chapter then looks at polymer stereochemistry; structure-property relationships; and polymer processing. It also considers the thermal methods of polymer analysis, in which some physical property of a substance is measured as a function of temperature or time while the substance is subject to a controlled temperature programme. The most common techniques are differential scanning calorimetry, thermal gravimetry, dynamic mechanical analysis, dilatometry, heat-deflection temperature, and melt index.
Three-dimensional networks
Authors: Walton David J. , Lorimer J. Phillip
Published: September 2023

This chapter focuses on three-dimensional networks, which are the toughest and most rigid materials, since the polymer chains are linked together in all directions to give effectively a single giant molecule. Three-dimensional networks do not melt, although segments may go through phase changes with temperature. They are insoluble, although lightly cross-linked ones can be solvent-swollen. They are therefore prepared in two stages, the first giving a processable intermediate that becomes the intractable final product in the second one. These principles are demonstrated for several systems, including Bakelite (phenol-formaldehyde polymers) and fibre glass (linear unsaturated polyesters), and also the vulcanization of rubber. Polymers which set hard after heating, usually because of a thermal cross-linking reaction, are called thermosets. The chapter then looks at electron beam cross-linking and physical cross-linking.
Functional polymers
Authors: Walton David J. , Lorimer J. Phillip
Published: September 2023

This chapter reviews the recent developments in functional polymers. It begins by looking at high performance polymers, which refers to polymers with extreme mechanical strength and toughness. The strategy to achieve this is instructive, since enhancement of one specific property occurs at the expense of other properties and eventually the best practical system involves a trade-off between desired features and those attainable. The chapter then considers electrically conducting polymers. Polymers are best known for their effectiveness as electrical insulators, and electrical wiring throughout the world is now sheathed in plastic. The chapter also examines polymers with functionalized side chains, as well as polymeric photoresists. It assesses the role of polymers in the ecosystem, addressing key issues such as the bioproduction of useful technological polymers, remediation and biodegradability, and waste treatment and recycling.
Introduction
Authors: Pete Biggs
Published: September 2023

This chapter discusses the use of computers in chemistry for applications that range from control of equipment and data acquisition to accessing databases both locally and on remote systems. It provides basic knowledge of the history of computing, beginning with Charles Babbage, who is the father of mechanical calculating machines. It also reviews the symbiotic relationship between chemistry and computing, as the presence of computers opened up new areas of chemical research while chemistry became a major contributory factor in the development of larger and faster computers. The chapter talks about crystallographers, who were the first significant users of computer power within the chemistry community. It focuses on digital electronics, which is simpler than analogue electronics as it only has two possible states: on or off.
Software for the laboratory
Authors: Pete Biggs
Published: September 2023

This chapter looks at what software does when used in instrumentation. It defines the concept of the master/slave set-up, wherein the master computer, or PC, decides on the general strategy while the slave computer performs the actual tasks. It also mentions that some slave computers are not physically located in the instrument but instead manifest as an interface card in the PC, which is beneficial when transferring large amounts of data between master and slave as it will speed up the process. The chapter refers to modern instruments that have some form of intelligence built into them. These are still capable of working in a master/slave environment, even if they have enough built-in intelligence to be stand-alone machines. The chapter addresses the issues on how to get data from an instrument to a computer and what can be done with them.
Presenting information
Authors: Pete Biggs
Published: September 2023

This chapter highlights some of the techniques for presenting results in a logical and understandable manner using computers. It considers the modern word processor, which will always include a form of rudimentary drawing package and spreadsheet capabilities which can be used for formatting equations. It also mentions Microsoft Word and Word Perfect as the most commonly used word processing packages world-wide. However, these packages are rivalled in the scientific community by the TeX document processing package, which is favoured by mathematicians and theoretical chemists. The chapter outlines some guidelines in scientific writing, such as making sure that the style is not too quirky and being wary of grammatical errors. It explains that the way equations are presented depends on whether they are chemical or mathematical.
Bibliography
Authors: Pete Biggs
Published: September 2023

Reference
Chemical energetics
Authors: Lawrence Nathan , Wadhawan Jay , Compton Richard
Published: September 2023

This chapter includes problems and answers that illustrate Hess's law, enthalpies of formation, bond enthalpies, lattice energies, and the stability of solids. It discusses enthalpy and entropy changes that accompany reactions, and reviews the prediction of direction of chemical change via free energy changes. It also introduces the temperature variation of enthalpy changes and heat changes at constant pressure as compared to constant volume. The chapter highlights the second law of thermodynamics and the prediction of the direction of chemical changes, including the Ellingham diagrams and the Born-Landé equation for the prediction of lattice energies. It emphasizes that the standard enthalpy of formation of a compound is the enthalpy change involved in the formation of one mole of the substance from its elements.
Coordination chemistry
Authors: Kaltsoyannis Nikolas , Scott Peter
Published: September 2023

This chapter evaluates the coordination chemistry of the lanthanides and actinides, which has as much in common with that of groups one and two as it does with that of the d block. At the same time, the unique characteristics of f block complexes have required the development of new techniques for investigation of their chemistry, and have subsequently led to a growing number of technological and scientific application in, for example, medicine and catalysis. Of growing concern to the public at large is what happens to the products of the nuclear power and fuel reprocessing industries after their release into the environment. Coordination chemistry is at the heart of unravelling this issue. The chapter then looks at actinyl ions; chelate and macrocyclic complexes; and alkoxides and dialkylamides. It also considers the role of lanthanides in organic chemistry and catalysis.
From Molecules to Crystallizers
Authors: Davey Roger J. , Garside John
Published: September 2023

From Molecules to Crystallizers begins by stating that crystallization is one of the oldest separation processes used in the chemical industry and is still one of the most important. It is also going through an exciting renaissance, the text argues, with the result that it is becoming yet more central to the needs of the modern chemical industry. As well as its long-standing use in the commodity chemicals business, it is central to the fine and speciality areas. The emphasis on crystallization has thus been changing from the simple production of bulk solid particles to one in which ever higher standards and reproducibility of particle size, size distribution, crystal form and particle morphology are demanded in both product and process development.
Nucleation
Authors: Davey Roger J. , Garside John
Published: September 2023

This chapter discusses nucleation, which is central to all types of crystallization. Nucleation is the process of creating a new solid phase from a supersaturated homogenous mother phase. The chapter derives a kinetic expression for the rate of nucleation and then extends the concepts involved to show simultaneous nucleation of two phases in a polymorphic system and nucleation in constrained volumes. It also considers heterogeneous systems in which nucleation can be catalysed by the presence of an existing surface in the form of ill-defined ‘dust’, seeds of the crystallizing material (secondary nucleation), or pre-ordered molecular species such as monolayers or micelles. Finally, the chapter looks at the techniques for detecting nucleation events.
Characteristics of continuous and batch crystallizers
Authors: Davey Roger J. , Garside John
Published: September 2023

This chapter describes the characteristics of continuous and batch crystallizers. The ‘mixed product removal’ assumption of the MSMPR crystallizer ensures that crystals of all sizes have the same mean residence time, which is also equal to that of the solution. If crystals have mean residence times that depend on their size, considerable extra flexibility of operation is achieved and greater variations in the crystal size distribution are possible. Meanwhile, batch crystallizers are widely used in the production of speciality, agro-, and pharmaceutical chemicals where the production rates are comparatively low. In discussing batch crystallization, the emphasis tends to be on the mode of operation rather than on the design of a specific piece of equipment.
Maxwell distribution of molecular speeds
Authors: Bowley Roger , Sánchez Mariana
Published: September 2023

This chapter starts with ideas from James Clerk Maxwell's publication the distribution of the speeds of particles in a gas, which he obtained by analysing collision processes between the particles. It recounts how Maxwell showed that there could be a distribution of speeds and calculated the distribution, contradicting people's speculation that the particles of the gas moved with the same speed. It also mentions Ludwig Boltzmann, who treated the kinetic theory of gases from a microscopic point of view using the notion of probability. The chapter details how Boltzmann derived Maxwell's distribution of speeds and related it to the temperature of the particles. It examines particles using quantum mechanics and derives the Maxwell distribution of speeds.
Numerical solutions
Authors: de Levie Robert
Published: September 2023

This chapter examines the numerical solutions of pH problems in order of their increasing complexity, and of the sophistication and numerical prowess of the tools needed for their solution. First, it uses the logarithmic concentration diagram to visualize the proton condition. It then considers methods that need no tools beyond a piece of paper and a pencil, before looking at those methods that require a simple calculator capable of computing square roots and taking logarithms. The chapter also describes general methods based on relatively simple iterative methods, such as a Newton-Raphson algorithm. Because iterations are repetitive, such calculations are most readily performed on a computer, using generally available software such as a spreadsheet or scientific calculators. Finally, the chapter explores some even more general approaches used in commercial programs that solve an arbitrary number of equilibrium expressions and the associated mass and charge balance equations.
Activity effects
Authors: de Levie Robert
Published: September 2023

This chapter addresses activity effects. The experimental evidence from almost a century of precise measurements of equilibrium constants shows that, in dilute solutions, they are essentially constant only when compared at constant ionic strength. By excluding the contributions from uncharged species, the ionic strength clearly reflects coulombic interactions. It is important to realize where activity corrections apply, and where they do not. Since interionic attractions can lower the energetics of ions, they can affect the numerical values of the equilibrium constants. However, activity effects have no direct influence on the mass and charge balance equations. Similarly, activity effects do not change the equivalence volume in a titration, but can change the shape of the titration curve. The chapter then looks at ionic interactions and non-ionic interactions.
Potentiometric sensors
Authors: Brett Christopher M. A. , Brett Ana Maria Oliveira
Published: September 2023

This chapter describes the functioning of potentiometric sensors, how they can be usefully employed, and in which experimental situations. Potentiometric sensors work through the measurement of an equilibrium potential, i.e. the potential at zero current, of the sensor versus a suitable reference electrode. These potentials are a function of the activity of the species in solution, not of their concentration. The Debye–Hückel equation relates concentrations to activities and can often be employed; indeed, potentiometric measurements can be used to test the Debye–Hückel theory. For potentiometric sensors to be useful, they must have a sufficiently fast response and be sufficiently selective in media containing various species, besides having a sufficiently good detection limit. The chapter then considers the functioning of ion-selective electrodes; the types of selective electrodes; miniaturisation strategies; and the criteria for choosing a potentiometric sensor.
Defects, impurities, and surfaces
Authors: Cox P. A.
Published: September 2023

This chapter talks about crystals containing defects and impurities, and surfaces which lead to a break in the regular periodicity of the crystal lattice and perturbation in the electronic structure. It cites the application of semiconductors in solid-state devices that depend on the electronic levels of deliberately introduced impurities. It also highlights the electronic consequences of defects and surfaces in a variety of different types of solid. The chapter outlines point defects, which are perturbations of the crystal that involve a single lattice site or a small group of sites. It discusses the charge on an individual defect. This plays an important role in its electrical properties and elementary defects in ionic solids, introducing an imbalance of ions of different types.
Quinolines and isoquinolines
Authors: Davies David T.
Published: September 2023

This chapter assesses quinolines and isoquinolines. Quinoline and isoquinoline are two isomeric heterocyclic systems, which can be envisaged as being constructed from the fusion of a benzene ring at the C2/C3 and C3/C4 positions of pyridine respectively. They are both ten π-electron aromatic heterocycles. Like pyridine, they are moderately basic. Indeed, quinoline is sometimes used as a high boiling-point basic solvent. As with pyridine, the nitrogen atoms of quinoline and isoquinoline each bear a lone pair of electrons not involved in aromatic bonding which can be protonated, alkylated, or complexed to Lewis acids. The chapter then considers the synthesis, electrophilic substitution, nucleophilic substitution, and anion chemistry of quinoline and isoquinoline.
Indoles
Authors: Davies David T.
Published: September 2023

This chapter focuses on indoles. Fusion of a benzene ring onto the C2/C3 positions of pyrrole formally produces the corresponding benzopyrrole known as indole. Indole is a ten π-electron aromatic system. As with pyrrole, delocalization of the lone pair of electrons from the nitrogen atom is necessary for aromaticity. A consequence of this delocalization is that the lone pair is not available for protonation under moderately acidic conditions. Pyrrole is therefore just like indole, another weakly basic heterocycle. Another similarity to pyrrole is that being an ‘electron-rich’ heterocycle indole easily undergoes aromatic electrophilic substitution, and is also rather unstable to oxidative conditions. However, an important difference emerges here, in that whereas pyrrole preferentially reacts with electrophiles at the C2/C5 positions, indole substitutes selectively at the C3 position. The chapter then looks at the synthesis, electrophilic substitution, and anion chemistry of indoles.
Oxidation of activated carbon–hydrogen bonds
Authors: Donohoe Timothy J.
Published: September 2023

This chapter evaluates the oxidation of activated carbon–hydrogen bonds. During the course of an oxidation, hydrogen can be removed in three ways, as either H+, H*, or H-. Normally, it is beneficial to have a functional group which stabilises the carbon left behind by such removal of hydrogen. As such, the chapter considers the hydrogen atom that is lost, activated by the functional group. It begins by looking at oxidation adjacent to oxygen. This is the most useful and widespread area of oxidation, as it encompasses the alcohol-aldehyde-carboxylic acid sequence which is used so often in synthesis. The chapter then studies oxidation adjacent to a carbon–carbon multiple bond, a carbonyl group, and nitrogen, as well as the oxidation of phenols and the formation of quinones.
Reduction of carbon–carbon double and triple bonds
Authors: Donohoe Timothy J.
Published: September 2023

This chapter addresses the reduction of carbon–carbon double and triple bonds. In particular, it examines ways of reducing multiple (π) bonds between carbon atoms by the addition of hydrogen (a process known as hydrogenation). The chapter begins by looking at the reduction of alkenes. Reaction of an alkene with hydrogen gas and one of the transition metal catalysts results in the reduction of the π-bond and formation of an alkene. The mechanism by which heterogeneous hydrogenation proceeds is complex and difficult to study as the reaction takes place on the surface of the metal, and the nature of this surface varies with the different catalysts used. The chapter then considers the reduction of alkynes and aromatic π-systems.
α-Heteroatom-stabilized organometallic reagents
Authors: Jenkins Paul R.
Published: September 2023

This chapter looks at carbanions that form an sp3 carbon atom α to a nitrogen atom, in which the presence of an appropriate electron withdrawing substituent on the nitrogen atom facilitates α-deprotonation. It describes the substituent Z as an electron withdrawing group that has lone pairs that stabilize the deprotonated structure by co-ordination. It also discusses the ideal activating group Z, which is easily attached to the nitrogen and is stable to the strong base required for deprotonation. The chapter reviews amides that are useful activating groups for α-deprotonation but require stringent conditions in order to be removed. It highlights α-deprotonation observed in a wide variety of cases and anions that react with a range of electrophiles.
Electrophilic rearrangements
Authors: Harwood Laurence M.
Published: September 2023

This chapter deals with electrophilic rearrangements in which a group migrates formally as cationic species. It mentions the intramolecular electrophilic rearrangement which has four electrons involved in the transition state, of which one pair is accommodated in an antibonding orbital of the migrating species. It also describes the anionic migration terminus that acts as the nucleophile. The chapter considers the interaction of the highest occupied molecular orbital (HOMO) with the lowest unoccupied molecular orbital (LUMO) of the migrating group. The chapter analyses crossover experiments which demonstrate that the rearrangement is largely intramolecular and is consistent with a tightly bound dissociative pathway. It analyses the conversion of the initial carbanion to the thermodynamically stable alkoxide, which becomes a driving force for a reaction.
Introduction
Authors: Moody Christopher J. , Whitham Gordon H.
Published: September 2023

This chapter analyzes the reaction of organic chemistry which proceeds by way of reactive intermediates according to a schematic equation. It discusses how the intermediate represent an isolable compound or a species in rapid equilibrium with reactants. It also explains how reactive intermediates correspond to a relatively shallow dip in a free energy versus reaction co-ordinate diagram and how they proceed to products faster than returning to starting material. The chapter explains the significance of the reactive intermediate when the depth of the free energy well containing it is sufficient to prevent every molecular vibration along the reaction co-ordinate proceeding back to reactants or forward to products. It describes reactive intermediates of organic chemistry as charged species, such as carbocations or carbanions.
Reactions of arenes
Authors: Sainsbury Malcolm
Published: September 2023

This chapter examines the reactions of arenes. If benzene is reacted with a reagent R, it is reasonable to conclude that should R be positively charged (an electrophile), the process will be easier than when R is negative (a nucleophile). For these reasons, electrophilic substitution is commonplace, whereas nucleophilic substitution only occurs under special circumstances. The energy profile of an electrophilic substitution reaction with benzene as the substrate can be represented diagrammatically. In order that the reaction should progress to the final product, another transition state is traversed in which the sigma bond to the proton of the tetrahedral carbon atom weakens and eventually breaks. There is much evidence for the formation of sigma complexes. The chapter then looks at π complexes.
Common electrophilic reactions
Authors: Sainsbury Malcolm
Published: September 2023

This chapter investigates common electrophilic reactions, including nitration, sulfonation, halogenation, acylation, and alkylation. In nitration reactions, the nitronium ion is the electrophile; this is generated through initial protonation of nitric acid. Any acid stronger than nitric acid will promote the reaction, but concentrated sulfuric acid is the usual choice. Meanwhile, benzene is sulfonated by heating it with concentrated sulfuric acid at ca 80 °C. Chlorine and bromine enter into substitution reactions with benzene, provided a Lewis acid is present. The role of the carrier is to form a complex with the halogen, thereby polarizing the homonuclear bond. Lewis acids are also necessary in alkylation and acylation reactions of benzene with alkyl halides and acyl halides respectively. These are known as Friedel-Crafts reactions. The chapter also looks at electrophilic metallation reactions.
Wider aspects of aromaticity
Authors: Sainsbury Malcolm
Published: September 2023

This chapter explores wider aspects of aromaticity. It begins by looking at aromatic carbocycles and heterocycles. The Hückel rule predicts that certain planar cyclic molecules, built up through the union of sp2 hybridized carbon atoms, should show aromatic character. In principle, however, other atoms can replace carbon, provided that they contribute an appropriate number of p electrons to the π system. Six atoms in a ring are not always required, and the five membered heterocycles pyrrole, furan, and thiophene are also aromatic molecules. More than one heteroatom can be incorporated into the ring and these atoms do not necessarily need to be identical. As a result, there are many aromatic heterocycles, both monocyclic and polycyclic. The chapter then considers the annulenes.
The shikimic acid pathway: biosynthesis of phenols, lignans, flavonoids, etc.
Authors: Mann John
Published: September 2023

This chapter emphasizes the pivotal importance of shikimic acid in metabolism as it is the progenitor of the aromatic amino acids phenylalanine, tyrosine, and tryptophan. The chapter reviews the discovery of the importance of the shikimic acid which arose from the studies of mutants of the bacterium Escherichia coli. It also mentions certain mutant strains which were obtained following the exposure of the parent bacterium to ionizing radiation that grow in the presence of amino acids, para-aminobenzoic acid, and para-hydroxybenzoic acid. The chapter analyszes the bacteria possessing modified genes which could not code for the production of the enzymes needed to convert glucose into key acids. It explores the biosynthetic pathway to shikimic acid, which begins with the reaction of phosphoenol pyruvate with the four-carbon sugar erythrose-4-phosphate.
Foundations of Organic Chemistry
Authors: Hornby Michael , Peach Josephine
Published: September 2023

Foundations of Organic Chemistry offers an introduction to this subject which is at the core of chemistry. The first three chapters introduce some basic physical chemistry, and lay the groundwork for the mechanistic organic chemistry covered later in the book. The importance of bonding and mechanism are stressed throughout, and readers are encouraged to apply their chemical knowledge in new and unfamiliar situations in order to develop and sustain their interest. A wide range of examples including natural products and pharmaceuticals is included, with the final chapter exploring some new developments and providing an introduction to current research.
Molecules
Authors: Hornby Michael , Peach Josephine
Published: September 2023

This chapter provides an overview of organic chemistry. Organic chemistry began as the chemistry of living things, like yeast, moulds, mushrooms, willow trees, and whales. It is based on the compounds of carbon, the molecules of which are the essence of organic chemistry. The chapter then looks at the ways in which atoms join together to form molecules. It considers how electrons are distributed in separate atoms. It focuses on carbon atoms. Chemical reactions are the result of bond breaking and bond making, involving the most energetic, outer shell electrons of atoms. Two factors influencing the strength of a bond are its type and the sizes of the atoms involved. The chapter also examines stereochemistry, intermolecular attractions, and solubility.
Mechanisms
Authors: Hornby Michael , Peach Josephine
Published: September 2023

This chapter discusses organic reaction mechanisms, which are shorthand descriptions of how starting compounds are made into products. Molecules with the same functional groups usually react using similar mechanisms, and we can use mechanisms for known reactions to predict how other molecules will behave under similar conditions. Mechanisms are thus a connecting thread between similar reactions and allow us to rationalize the products of a known reaction and to predict the reactivity of other organic molecules. The chapter considers the mechanisms of three types of reaction: substitution, addition, and elimination. It then looks at nucleophiles, electrophiles, and radicals. The chapter also studies the process of drawing mechanisms using dot diagrams and curly arrows.
Taking it further
Authors: Hornby Michael , Peach Josephine
Published: September 2023

This chapter explores new developments in organic chemistry. There is a need for theories, but all good theories are firmly based on facts. ‘How do you know that?’ and ‘How do you show that this statement is true?’ are questions we will be asking more often in the future. It is in answering these questions that the armoury of techniques of the modern organic chemist comes into play, from chemical kinetics to nuclear magnetic resonance (NMR) spectroscopy and X-ray crystallography. The chapter then looks at mechanisms and molecular orbitals, before considering functional group chemistry. It also highlights some current research projects in organic chemistry, including the biosynthesis of ethane; the synthesis of new anti-cancer agents; and fluorescent indicators for calcium ions.
Getting started
Authors: Compton Richard G , Sanders Giles H W
Published: September 2023

This chapter traces the origin of electrode potentials, showing their relationship with chemical thermodynamics and indicating why their measurement is important in chemistry. It analyses the consequence of electrons moving from the metal into the solution phase. It also describes how the metal becomes positively charged while the solution become negative, wherein the charge transfer is the fundamental reason for the potential difference predicted by the Nernst equation. The chapter talks about how the energy level both in the metal and solution must change as the electron transfer proceeds and the solution and metal become charged. It discusses the positive charge that evolves on the electrode wherein the energy of an electron in the metal must be lowered.
Allowing for non-ideality: activity coefficients
Authors: Compton Richard G , Sanders Giles H W
Published: September 2023

This chapter reviews the development of the relationship between activity and concentration, illustrating the chemical potential of an ideal solution that depends on whether it deals with the concentrations or mole fractions. It shows how the enthalpy of mixing is zero for ideal solutions, which can be interpreted in the terms that the intermolecular forces between the molecules in the mixture are equal to those in the pure liquids. It also points out that the equality of interaction forces is considered as an alternative way of describing an ideal solution. The chapter emphasizes that non-ideality must arise from grossly dissimilar inter-particular forces. It considers that electrodes and their potentials must use activities rather concentrations when opting for the Nernst equation.
Spectroscopic techniques for probing solid surfaces
Authors: Attard Gary , Barnes Colin
Published: September 2023

This chapter examines a range of surface-sensitive spectroscopies which are capable of providing detailed information concerning the geometric structure, chemical composition, and electronic properties of a solid surface. Although selective, a basic discussion of the physicochemical principles involved and the type of information they provide is possible. The chapter begins by looking at the two major techniques utilized to gain information on surface chemical composition: X-ray photoelectron spectroscopy and Auger electron spectroscopy. This is followed by a consideration of methods suitable for elucidating surface structure, including both a diffraction-based approach (low-energy electron diffraction) and more direct probes based on electron tunnelling (scanning probe microscopies). Finally, the chapter studies spectroscopies to investigate surface chemical bond formation and reactivity, such as ultra violet photoemission, vibrational spectroscopies (reflection-absorption infra red and high resolution electron energy loss), the strength of surface bonding (thermal desorption spectroscopy), and surface reaction rates (molecular beam spectroscopies).
Worked examples and problems
Authors: Attard Gary , Barnes Colin
Published: September 2023

This chapter presents some worked examples and problems to further illustrate the topics discussed in the previous chapters. A problem concerns the deposition of a metal film on to a Cu substrate, which leads to a decrease in intensity of the Cu 60 eV kinetic energy Auger peak. We should determine graphically the value of the inelastic mean free path for 60 eV Auger electrons. This example provides an expression for the decrease in substrate Auger intensity as a function of film thickness d at normal emission. Ultimately, inelastic mean free paths are determined by measuring the decrease in substrate XPS or Auger peaks as a function of film thickness. The analysis relies on the fact that growth occurs in a layer by layer fashion, which is often not strictly true, leading to a degree of scatter in experimental values.
Structure of the electrode/ solution interface
Authors: Fisher A. C.
Published: September 2023

This chapter discusses the forces that govern the behaviour of electrolytes in bulk solution, which are disrupted by the discontinuity at the interface. It describes the nature of the electrode/electrolyte interface and the phase boundary between the solid electrode and the electrolyte solution that interrupt the nature of the electrolyte solution. It also mentions the electrode which possesses a charge that can be controlled by the potential applied to the electrode and the electrode that has interactions with dipole moments of the solvent molecules. The chapter looks at models that have been developed to establish the nature of the processes at the solid or liquid interface. It refers to Hermann von Helmholtz, who proposed a simple model that describes the electrode/electrolyte interface in 1853.
Spectroelectrochemistry
Authors: Fisher A. C.
Published: September 2023

This chapter deals with the molecular identity of the species, particularly intermediates, that must be indirectly inferred. It discusses the employment of electrochemical studies in combination with spectroscopic measurements in order to provide more direct characterization. It also explains the additional information obtained from spectroelectrochemical measurements that open the door to the investigation of a wide range of complex surface and homogeneous processes occurring in electrochemical systems. The chapter highlights the structure characterization of the electrode surface, the identification of homogeneous phase molecules, and the study of species absorbed at the electrode/electrolyte interface. It cites the ideal characterization of electrode surfaces that requires information on atomic resolution.
Reactivity of macrocyclic complexes
Authors: Constable Edwin C.
Published: September 2023

This chapter assesses the reactivity of macrocyclic complexes. It looks at axial substitution reactions and reactions of the coordinated macrocyclic ligand. The chapter also considers demetallation and metal exchange reactions, as well as metal-centred oxidation and reduction reactions. Finally, the chapter covers ligand-centred redox processes. Numerous examples are known in which macrocyclic ligands undergo this type of redox process. Direct hydrogenation reactions of both free ligands and metal complexes are possible, although reactions of the free ligands are perhaps more common. Oxidation of a coordinated macrocyclic ligand is also a more commonly observed process, and it is convenient to distinguish between oxidation processes which involve the addition of oxygen atoms and those which involve the loss of hydrogen atoms.
Modelling biomolecules
Authors: Guy H. Grant , W. Graham Richards
Published: September 2023

This chapter focuses on methods for modelling protein structures. In many circumstances it is now possible to make a reasonable prediction of the structure of a protein from its sequence. Multiple sequence data also allow the identification of the most likely mutations at particular positions across a family of homologous proteins. Extension of this information to include different structural classes provides excellent tools to approach the inverse folding problem. Once a sequence of unknown structure has been matched with a known structure, homology modelling methods can be used to effect the transformation of one structure into the other. Theoretical investigations of enzyme mechanisms are now also a possibility. Such methods are proving to be useful in understanding the molecular basis of enzyme activity.
Two-phase liquid-liquid reactions
Authors: B.G. Cox
Published: September 2023

This chapter assesses the reactions that occur across phase boundaries or involve transport of reactants between phases. These are important in laboratory chemical reactions, industrial processes, biochemistry, and physiology. It mentions transport processes in cells. These are required to maintain and regulate the ionic balance across cell membranes. It also discusses two-phase conditions in industrial processes which result from the requirement of high productivity in systems which are normally studied under homogeneous conditions. The chapter reviews cases wherein heterogeneous conditions are dictated by the low mutual solubility of the reactants. It clarifies chemical reactions which occur within one phase, but where the reagent concentrations and reaction rates are influenced by the presence of the second phase.
Substitution at four- coordinate sites
Authors: Henderson Richard A.
Published: September 2023

This chapter refers to transition metal sites associated with a coordination number of four, focusing on substitution mechanism by looking at tetrahedral metal sites. It explains that the reactions of the coordinately saturated, tetrahedral complexes exhibit very simple kinetics—a first order dependence on the concentration of the metal complex and independence of the concentration and nature of the reacting nucleophile. The chapter reviews the interpretation of these simple kinetics in terms of a dissociative mechanism, which is further substantiated by extra kinetic parameters. The chapter mentions the rates of reaction of nitrosyl systems that are sensitive to both the concentration and nature of the nucleophile, which is a characteristic of associative mechanisms.
Activation of ligands
Authors: Henderson Richard A.
Published: September 2023

This chapter analyses the general reactivity of the ligand, which defines elementary reactions in catalysis that involve metal sites and action of metalloenzymes at the atomic level. It looks at factors controlling the attack of hydroxide at organic carbonyl compounds which are of direct relevance to the action of the zinc-containing enzymes carboxypeptidase and carbonic anhydrase. It also mentions the factors that favour the protonation and reduction of coordinated dinitrogen, which are important to the understanding of the action of the nitrogenases. The chapter considers the interaction between a metal and a ligand that reveal several types of bonding. It outlines how the ligand is more susceptible to attack by nucleophiles and bonds within the ligand that may be prone to cleavage.
Alkylidene and alkylidyne complexes
Authors: Bochmann Manfred
Published: September 2023

This chapter studies alkylidene and alkylidyne complexes. Whereas metal alkyl complexes have a long history, the first examples of compounds with metal–carbon double bonds were not discovered until 1964 by E. O. Fischer. These compounds have become known as carbene complexes. The metal is in a low oxidation state, and the bonding of the carbene ligand is reminiscent to that of carbon monoxide (CO). A second group of M=C compounds, with a highly oxidized metal centre, was subsequently discovered by R. R. Schrock and these are called alkylidene complexes. The chapter then considers complexes with metal–carbon triple bonds, as well as the reactivity of alkylidene and alkylidyne complexes and it also looks at dinuclear alkylidene and alkylidyne complexes.
Dioxygen management—storage and transport
Authors: Fenton David E.
Published: September 2023

This chapter evaluates the storage and transport of dioxygen. When we breathe, dioxygen enters our bloodstream through interaction with the iron atoms present in our oxygen-carrier haemoglobin and then is carried to the tissues where it is stored by myoglobin until it is required for metabolic processes. The dioxygen carriage and storage proteins are called respiratory pigments and are required by all animals and many other species. Not all species, however, use haem proteins. Molluscs and arthropods such as lobsters, squid, cuttlefish, and octopi use haemocyanin, a dinuclear copper protein which absorbs one molecule of dioxygen per two metal atoms and gives the blood a blue colour. Certain marine worms use haemerythrin, a diiron non-haem protein which gives their blood a violet colour.
Dioxygen management-involvement in enzymes
Authors: Fenton David E.
Published: September 2023

This chapter assesses the involvement of dioxygen in enzymes. Enzymes are large proteins which catalyze biochemical reactions. Like all proteins, they are essentially polypeptides. One requirement for life is the maintenance of molecules in a reduced state even though they are exposed to an oxidizing atmosphere. A further requirement is the production of energy which is accomplished by respiration in which dioxygen is reduced to water. The superoxide and peroxide anions are powerful oxidizing agents and present a threat to life. Therefore, it is necessary to remove them. Two main methods are available for removing hydrogen peroxide: disproportionation and reduction. The former is catalyzed by catalases and the latter by peroxidases — both species are haemprotein enzymes. The chapter then looks at superoxide dismutases; oxidases and oxygenases; and ribonucleotide reductase.
Amines
Authors: Bailey Patrick D. , Morgan Keith M.
Published: September 2023

This chapter introduces the features of nitrogen. It recognises nitrogen as the most abundantly gas in the world despite its lack of reactivity. Next, the chapter highlights the flexible organic compounds which can be combined with the presence of nitrogen. It looks into neutral nitrogen, trivalent nitrogen, and common organonitrogen functional groups. The chapter also discusses the components of saturated nitrogen compounds. It highlights the importance of nitrogen in organic chemistry and the significance of organonitrogen chemistry in the evolution of life. In terms of modern life, organonitrogen chemistry is linked to natural products such as DNA, peptides, proteins, alkaloids, man-made pharmaceuticals, fibres, and dyes.