bluuebunny/crossref_metadata_2025 huggingface dataset:
Aromatic Chemistry
Authors: Sainsbury Malcolm
Published: September 2023

Aromatic Chemistry presents all the basic principles of this important topic in an account which takes as its examples many compounds of industrial and biological significance. Consideration is given to the structure, reactions, and properties of benzene and classes of aromatic compounds derived from it, and topics such as thermodynamic versus kinetic control and pericyclic reactions are introduced. The text also covers polycyclic arenes and the small and large ring systems which are embraced by the wider definition of aromaticity.
Aromatic character and the structure of benzene
Authors: Sainsbury Malcolm
Published: September 2023

This chapter discusses the aromatic character and the structure of benzene. Benzene C6H6 is a component of coal tar distillate and an aerial pollutant found in the exhaust gases of automobiles. It is the parent of a group of compounds known as arene, which exhibit different reactions to those shown by other unsaturated hydrocarbons, i.e. alkenes. Arenes are also described as aromatic molecules. The term aromatic is historical and derives from the fact that many naturally occurring fragrant compounds were observed to contain a benzene unit. Nowadays aromaticity has a wider scientific meaning and refers to planar cyclically conjugated structures having (4n+2) π electrons (where n is 0, 1, 2 etc.), Hückel's rule. The chapter discusses resonance and the π electron system of benzene, the representation of benzene, the importance of Hückel's rule, and nomenclature and numbering of benzenes.
Alkaloids
Authors: Mann John
Published: September 2023

This chapter focuses on alkaloids, which are non-peptidic and non-nucleosidic compounds which contain nitrogen and which are abundant in higher plants, insects, amphibians, and fungi. It cites cocaine, nicotine, mescaline, hallucinogenic constituent of the peyote cactus, and strychnine as typical examples of alkaloids. It also talks about alkaloids in the wild. These act as feeding deterrents or mediators of other types of chemical communication between organisms or as mediators of ecological interactions. The chapter recounts how alkaloids first evolved during the time when the organisms had a surplus of amino acids for their primary metabolic requirements. It reviews enzymes that were involved in biosynthetic activities. These initially served as routes for the destruction of the amino acids.
Reactions with nucleophiles
Authors: Hornby Michael , Peach Josephine
Published: September 2023

This chapter focuses on organic reactions with nucleophiles. Nucleophiles are 'electron-rich' and have either non-bonded pairs of electrons or π-bonds; they can be anions or neutral molecules. Nucleophiles can react with species which have either positive charge or low electron density. This is the basis of many reactions, which begin with the transfer of electron density from the more electron-rich atom (in the nucleophile) to the more electron-deficient atom (in the electrophile). The chapter then looks at nucleophilic substitution reactions of haloalkanes; substitution reactions of alcohols; polymerization of cyclic ethers; the carbocation intermediate; and the competition between nucleophilic substitution and elimination. It also considers the reactions of nucleophiles with aldehydes and ketones; the reactions of nucleophiles with esters, carboxylic acids, and derivatives; the comparison of acid derivatives with aldehydes and ketones; and the comparison of the reactivities of the different types of halocompound with nucleophiles.
Reactions with electrophiles
Authors: Hornby Michael , Peach Josephine
Published: September 2023

This chapter assesses organic reactions with electrophiles. Electrophiles have centres of low electron density, which will accept an electron pair to make a covalent bond. There are three types: positively charged cations, neutral molecules, and radicals. We could also include as electrophiles all the organic molecules which react with the nucleophilic reagents in the previous chapter, e.g. the polarized haloalkanes and carbonyl compounds. The chapter then looks at the addition of hydrogen halides to alkenes; the reactions of alkenes with sulfuric acid; the addition of halogens to alkenes; the cationic polymerization of alkenes; and the oxidation of alkenes. It also considers benzene and related compounds, studying the electrophilic substitution of benzene; the oxidation of benzene and related compounds; and the comparison between benzene and alkenes.
Reactions with radical intermediates
Authors: Hornby Michael , Peach Josephine
Published: September 2023

This chapter addresses homolytic reactions which involve radical intermediates. A radical has an odd unpaired electron and is normally uncharged. Radicals are electron-deficient in the sense that the atom carrying the unpaired electron is one electron short of a stable outer shell, such as carbon or chlorine with seven electrons instead of eight. The formation of radicals at the beginning of a reaction is called the initiation. The reaction then continues by the propagation steps, in which a radical reacts with a molecule to give another radical as one of the products. The propagation steps can go on and on to make a chain reaction, until two radicals combine to form a stable compound (termination reaction). The chapter then looks at the halogenation of hydrocarbons; catalytic hydrogenation; and the cracking of hydrocarbons. It also considers the radical polymerization of alkenes; enzyme-catalyzed radical reactions; and radical reactions in the gas phase.
Worked examples and problems
Authors: Compton Richard G , Sanders Giles H W
Published: September 2023

This chapter includes examples of problems based on standard electrode potentials, such as calculating the equilibrium constants for reactions at 25°C in aqueous solutions. It examines the strategy associated with a formal cell reaction with the cell, which includes the potential determining equilibrium at the right-hand electrode. It also explores a reaction that is thermodynamically downhill, which is the process that would occur if the cell was short circuited. The chapter talks about the spontaneous cell reaction which occurs when the cell is short circuited, and which depends on cell concentrations. It analyses the reaction that involves the pure solid metal chlorides and pure elements in their standard states, in which free energies evaluated are standard free energies regardless of the concentration of hydrochloric acid in the cell.
Gas adsorption at solid surfaces
Authors: Attard Gary , Barnes Colin
Published: September 2023

This chapter discusses gas adsorption by solid surfaces. It describes some key ideas relating to the interaction of gases with solids, starting with the Langmuir adsorption isotherm. The Langmuir isotherm has been used successfully to interpret equilibrium adsorption behaviour of a number of systems and in determining the total surface area of solid surfaces, particularly high surface area solids often used as heterogeneous catalysts. Meanwhile, the Brunauer, Emmett and Teller (BET) isotherm provides an extension of the Langmuir monolayer model to multilayer adsorption. The chapter then looks at the types of bonding interactions formed between gas molecules and solid surfaces, as well as the rate at which vacant adsorption sites are filled. Two broad classifications of adsorbate bonding may be distinguished depending on the magnitude of their enthalpies of adsorption: physisorption and chemisorption. The chapter also considers single crystal surfaces, the problem of surface sensitivity, and adsorbate–adsorbate interactions.
The spectra of many-electron atoms
Authors: Softley T. P.
Published: September 2023

This chapter considers the spectra of atoms in which there may be more than one electron with orbital angular momentum. It begins with a discussion on the coupling of orbital angular momentum before turning to Russell–Saunders coupling and jj-coupling. Next, the chapter considers the Zeeman and Stark effects. The Zeeman effect describes what normally happens in a magnetic field, and the Stark effect is concerned with an external electric field. From there, the chapter studies the laser magnetic resonance (LMR), a modern spectroscopic technique which makes use of the Zeeman effect. The hyperfine structure, atomic clock, and transition metals are also elaborated on. Lastly, the chapter considers the photoelectron spectroscopy of atoms and Rydberg states and autoionization.
Introduction
Authors: Fisher A. C.
Published: September 2023

This chapter provides a background to dynamic electrochemistry, which is the study of electron transfer reactions between electrodes and reactant molecules in a solution phase. It focuses on the development and application of techniques that measure the rate and mechanisms of reactions in the same way that the familiar methodology of homogeneous kinetics examines chemical reactions. It also looks at parameters that influence the dynamics of an electrode reaction. The chapter analyses the electrode potential, transport of material between electrode and bulk solution, and reactivity of the solution species, which control the rate of the charge transfer process. It summarizes important concepts from equilibrium electrochemistry.
Mass transport
Authors: Fisher A. C.
Published: September 2023

This chapter reviews physical processes that contribute to the overall kinetics of any particular reaction. It explains how the reactant molecule must be transported from the bulk solution to the electrode interface in order for electrolysis to proceed, and covers how the reaction products diffuse away from the electrode. It also analyses a particular reaction that may be controlled either by the kinetics of electron transfer or by the rate at which material is brought to or from the electrode mass transport. The chapter mentions mass transport effects that become important for the successful interpretation of experimental observations when electrolytic reactions are induced to occur rapidly. It highlights diffusion, convection, and migration as significant transport processes.
Introduction to macrocyclic chemistry
Authors: Constable Edwin C.
Published: September 2023

This introductory chapter provides an overview of macrocyclic chemistry. A macrocycle is a large cyclic molecule, and a macrocyclic ligand should contain donor atoms which may form coordinate bonds with metal centres. This book describes the synthesis and coordination chemistry of macrocyclic ligands. The coordination behaviour of macrocycles is no different in principle from that of open-chain polydentate ligands. But in practice, the unusual, and often unexpected, properties of the systems justify their being given special treatment. More recently, the high stability of macrocyclic complexes has been utilized in the construction of models for metalloproteins and in a wide range of technological applications. Particular interest has centred upon the use of macrocyclic ligands for the selective extraction of metals and the development of hydrometallurgical methods to replace conventional, and environmentally damaging, pyrometallurgy.
Artificial intelligence
Authors: Pocock Gillian , M Hugh
Published: September 2023

This chapter explores the extensive potential of artificial intelligence (AI), which has been recognized and harnessed by computer scientists, including physics and life sciences. It analyses how AI is applied to those areas of chemistry that offer great scope for investigation by intelligent methods. It also defines AI as an attempt to replicate intelligent reasoning through ‘machines’, which the chapter uses in a sense that is much broader than its everyday meaning. It highlights the differences between the way scientific problems are tackled using conventional methods and the way they are solved using the alternative methods of AI. It discusses how computers can be persuaded to act intelligently and solve problems that may resist solution using ‘dumb’ methods.
Expert systems
Authors: M Hugh
Published: September 2023

This chapter describes the ‘expert’ as a valuable commodity in the field of science which requires a high level of technical understanding. It focuses on an expert system, which is a computerized clone of a human expert and contains a fund of knowledge relating to some specific, well-defined area. It also analyses how a computer can reproduce many of the logical deductions of a human expert and offer scientific advice of a quality rivalling that which a human might provide. The chapter outlines how expert systems operate and how they can be applied to science. It discusses how computers can reason and draw conclusions and mimic what is commonly known as ‘thinking’.
Genetic algorithms
Authors: M Hugh
Published: September 2023

This chapter talks about genetic algorithms (GA), which are considered an optimization technique. This is, in other words, an intelligent way to search for the optimum solution to a problem hidden in a wealth of poorer ones. It explains that a GA works with a ‘population’ of individuals. It also clarifies how the individuals ‘mate’ with each other, ‘mutate’, and ‘reproduce’ in order to evolve through successive generations toward an optimum solution. The chapter discusses what characteristic of evolution acquires the ability to provide the inspiration for solving numerical problems and how its power can be harnessed in a most effective and intriguing way. It mentions the similarities of GA with other optimization and search methods in which any computational task involves mating, mutation, and reproduction.
Molecular mechanics
Authors: Guy H. Grant , W. Graham Richards
Published: September 2023

This chapter examines molecular mechanics. By bringing together features from both the Central Force Field and Valence Force Field methods, it proved possible to derive energy functions which were at once chemically intuitive while still retaining the concept of through space attractions and repulsions. The theoretical basis of the molecular mechanics method can be derived by taking an alternative approach to the Born–Oppenheimer approximation to that considered in molecular orbital methods. The chapter then looks at energy calculation, energy minimization, force field parameterization, and conformational analysis. Force field methods are finding increasing application in many areas of structural chemistry. Minimization of structures is usually required to remove strain from poorly defined geometries. Meanwhile, conformational search procedures often utilize molecular mechanics calculations, but one must be careful that the methods used do not introduce bias into the calculation.
Statistical mechanics
Authors: Guy H. Grant , W. Graham Richards
Published: September 2023

This chapter evaluates statistical mechanics. It explores the methods for simulating 'real' systems, as well as novel methods which can relate the calculated properties of small model systems to measured bulk properties. That solvation plays an enormous role in the determining properties of molecules is self-evident. The simplest methods for the simulation of the solvent are concerned with electrostatic screening and are incorporated in the calculation via the dielectric constant. Meanwhile, two principal methods are applied to the simulation of collections of methods. In the first, the Monte Carlo technique, random moves are made to the molecules and the energy differences tested according to their Boltzmann weighted probability of existing. In the molecular dynamics method, all changes are made subject to the inter- and intramolecular forces present in the system, via classical equations of motion. The chapter then looks at free energy calculations.
Complex reactions
Authors: B.G. Cox
Published: September 2023

This chapter emphasizes that the majority of chemical reactions have a mechanism which involves several elementary processes or reaction steps. These processes result in a reaction mechanism that is designated as complex. The chapter describes rate law and states that this is inconsistent with the stoichiometric equation and is considered to be the clearest indication of complexity. It also cites the oxidation of the formate ion by permanganate in water. The chapter talks about the establishment of the reaction by stoichiometry, which is more complex than a single bimolecular reaction step. The chapter also looks at second-order kinetics as it consists of a simple bimolecular encounter process. This includes reversible reactions that proceed towards equilibrium, concurrent reactions that control product distribution, and consecutive reactions in which the initial products act as reactants for subsequent reactions.
Substitution mechanisms at transition metal sites
Authors: Henderson Richard A.
Published: September 2023

This chapter starts off by looking at the substitution process, which is relevant to several areas of chemistry, such as the binding of substrates to the active site in both metalloproteins and homogeneous catalysts, and many electron transfer reactions. It refers to the discussion about substitution mechanisms in terms of coordination number, which proposes that each coordination type has a particular group of mechanisms that are different to those observed with other coordination numbers. It also refers to associative and dissociative mechanisms that are established in four-, five-, six-, and seven-coordinate complexes. The chapter looks at the three classes of substitution mechanisms, namely the associative mechanism, dissociative mechanism, and interchange mechanism. It analyses variations to the identity of the reaction mechanism that are associated with the relative heights of the barriers.
The oxidative-addition reaction
Authors: Henderson Richard A.
Published: September 2023

This chapter focuses on the oxidative-addition reaction of alkyl halides, wherein there is a simultaneous increase in the formal oxidation state of the metal and in its coordination number. It highlights the important aspect of the oxidative-addition reaction, which provides that ‘oxidative-addition’ does not describe the mechanism of a reaction but is just a stoichiometric definition of the result of the reaction. It also reviews the simple interaction between a metal site and an alkyl halide, which results in the oxidative-addition of the latter as the metal site acts as a nucleophile with respect to the carbon centre. The chapter discusses the analogous oxidative-addition reactions of H2. It looks at two different geometries for the transition state of the reaction with RX that have different stereochemical consequences on the reaction in relation to the alkyl group and metal site.
Quantum Mechanics 1
Authors: Green N. J. B.
Published: September 2023

Quantum Mechanics 1 starts from the basis that quantum mechanics is of central importance in chemistry. To understand matter and its chemical transformation it is necessary to take a microscopic view connecting experimental observation to the properties of constituent molecules. However, at this microscopic level, atoms and sub-atomic particles do not obey the classical laws of mechanics that pertain to the everyday macroscopic world. They obey the laws of quantum mechanics. This text explains the fundamentals of quantum mechanics from the point of view of chemistry; describes areas of chemistry where quantum mechanics is most important; and shows how quantum mechanics is applied to chemical problems. To this end, the book is divided into two parts: the first deals with the foundations of quantum mechanics (concentrating on exactly soluble problems and the reduction of complicated problems to simple foundations) and the second is a tool kit for applying quantum mechanics to chemical problems (thus concentrating on approximate methods).
Therapeutic uses of coordination compounds
Authors: Fenton David E.
Published: September 2023

This chapter discusses how coordination compounds have found application in medicine in the treatment, management, and diagnosis of disease. It focuses on two ways in which this occurs: the application of therapeutic chelating agents and the therapeutic use of preformed coordination compounds. Therapeutic chelating agents have been used to remove excess metals from the body. These might have arisen from metabolic disorders such as Wilson's disease, a hereditary genetic disorder in which the body is unable to metabolize copper in the normal way. The chapter then looks at the development of chelation therapy. Although preformed metal complexes have been used in medicine, it is perhaps the application of platinum complexes in cancer therapy that is the best-known example of the use of coordination complexes in the treatment of disease.
Organonitrogen Chemistry
Authors: Bailey Patrick D. , Morgan Keith M.
Published: September 2023

Organonitrogen Chemistry
introduces a wealth of fascinating organic chemistry involving nitrogen. There are three main sections to the book, each being introduced by a summary of the underlying chemical principles. The main organonitrogen functional groups are covered systematically, each chapter concluding with a brief summary of the chemistry. Topics include amines, ammonium compounds, nitrogen bases, and synthesis of amines. The second part of the book covers amines, ammonium compounds, nitrogen bases, and synthesis of amines. Finally, the text looks at compounds with N-N bounds, oximes,
N
-oxides, nitroso compounds and, nitro compounds.
Nitrogen bases
Authors: Bailey Patrick D. , Morgan Keith M.
Published: September 2023

This chapter discusses ammonium compounds. It looks into the general formula of ammonium compounds wherein it could be linked to alkyl, aryl, or hydrogen. The chapter notes the two distinct classes of compounds: hydrogen R groups and ammonium cations formed by the protonation of an amine. It lists the properties of quaternary ammonium ions as chirality, solubility in solvents and phase transfer catalysis. Elimination and reduction are regarded as the only important reactions in line with quaternary ammonium ions. Additionally, the chapter highlights quarternary ammonium ions being used as phase transfer catalysts to help transport counter-anions into an organic phase.
Urethanes, ureas, imides, and diimides
Authors: Bailey Patrick D. , Morgan Keith M.
Published: September 2023

This chapter explores nitriles which were previously formerly recognised as cyanides. It notes alkyl cyanides are less toxic than inorganic cyanides. The chapter discusses the properties of nitriles such as being unreactive due to their its low basicity of sp-hybridised nitrogen of nitriles. The most common way to achieve nitriles is by using inorganic cyanides to introduce the C=N unit. It uses the Streecher synthesis as a reference to the formation of nitriles. Additionally, the chapter enumerates the reactions of nitriles: hydrolysis, nucleophilic attack, enolate chemistry including the benzoin condensation and reduction. Thus, nitriles are relatively inert.
Molecular Spectroscopy
Authors: Brown John M.
Published: September 2023

Molecular Spectroscopy provides an introduction to the spectroscopy of diatomic molecules. Following a general introduction to the subject, the second chapter lays out the essential quantum mechanical tools required to understand spectroscopy. The following chapter uses this quantum mechanical framework to establish the selection rules which govern spectroscopic transitions. Chapters 4–7 describe the various branches of spectroscopy covered by the book; rotational, rotational—vibrational, Raman, and electronic spectroscopy. Quantum mechanics is used to derive formulae for the various energy levels involved and for the relative intensities of different types of transition. From these, the appearances of the different types of spectra are derived. The molecular parameters on which these spectra depend are defined and the structural information which can be derived from these is discussed.
Transition probabilities and selection rules
Authors: Brown John M.
Published: September 2023

This chapter explains how a spectroscopic experiment registers the change of a molecule from one quantum state to another, which is a process known as spectroscopic transition. It points out that the heart of the spectroscopic experiment is the exchange of energy between radiation and matter as the energy required to drive spectroscopic transition is provided by electromagnetic radiation. It also discusses the change of state brought about in a spectroscopic transition. This requires solving the time-dependent Schrödinger equation. The chapter looks at the transitions studied in molecular spectroscopy that involve the interaction between the electric dipole moment of the molecule and the electric field of the radiation. It refers to the conversion of energy expression to quantum mechanical form, which treats the field classically and the dipole moment quantum mechanically.
Introduction to synthesis
Authors: Willis Christine L. , Wills Martin
Published: September 2023

This chapter provides an overview of organic synthesis. The synthesis of a particular compound from commercially available starting materials is fundamental to nearly all aspects of organic chemistry. Thousands of organic compounds are naturally occurring and may be isolated from natural resources such as fungi, bacteria, and plants, but often not in sufficient quantities for a comprehensive study. In addition, many fascinating compounds are not naturally occurring and hence these molecules must be prepared to enable their properties to be investigated. The chapter then looks at bond polarity and free radical reactions. Most organic reactions involve heterolytic cleavage of bonds and reactions between positive or negatively charged or polarized species. However, organic compounds can also become involved in radical reactions, an area which is growing in importance in synthesis.
Some recent developments in inorganic materials chemistry
Authors: Weller Mark T.
Published: September 2023

This chapter explores some recent developments in inorganic materials chemistry. Many of these have come in the area of new materials. The chemistry of high temperature superconducting phases, in terms of the synthesis and structure of these compounds, lies within the area of this text. More recently, the structural chemistry of C60 in its ionic compounds is also relevant, though the chemistry of this species is developing rapidly in many areas. Consideration of several superconducting systems shows two features in common. They all contain planes of the stoichiometry CuO2 formed by linking CuO4 square planes at all vertices, and they all have an average copper oxidation state in excess of 2+. The chapter then looks at the structural chemistry of fullerenes and fullerides.
Reactions of diols
Authors: Ward Robert S.
Published: September 2023

This chapter describes 1,2-diols that undergo acid-catalysed rearrangement to afford ketones, which is a general reaction that involves the generation of a carbocation intermediate. It refers to the driving force of the general reaction of 1,2-diols that is provided by the resonance stabilization of the resulting carbocation. It also explains how diols react with aldehydes and ketones under anhydrous conditions to give acetals and ketals, which is a reaction that is acid-catalysed and proceeds most readily when the heterocyclic ring formed is five- or six-membered. The chapter discusses a transformation that can be used to protect aldehydes, ketones, and diols, while other reactions that involve base treatment or reduction are carried out elsewhere in the molecule. It demonstrates a reaction wherein diols are cyclized to form cyclic ethers; this can be carried out under acidic conditions.
Selective protection of bifunctional compounds
Authors: Ward Robert S.
Published: September 2023

This chapter addresses a problem which frequently arises with a molecule that contains two reactive functional groups: how can one carry out a selective reaction on one group without affecting the other? It clarifies how acetals can be used to protect aldehyde or ketone groups while transformations are carried out elsewhere in a molecule. It also implies that acetals can be used to protect diols and simple alcohols, noting that they are often preferable to simple ether protecting groups as they can be removed under very mild conditions. The chapter points out that tetrahydropyranyl and methoxymethyl ethers are actually acetals that can be easily removed via treatment with aqueous acid. The chapter also covers the selective protection and deprotection of carbohydrates and amino acids.
Reactions of nucleophiles with carbonyl compounds
Authors: Maskill Howard
Published: September 2023

This chapter assesses reactions of nucleophiles with carbonyl compounds. In the context of organic synthesis, reactions of carbonyl compounds are probably the most useful of all; they are also amongst the most varied. This is because carbonyl is both the functional group of simple aldehydes and ketones, and also a principal component of a range of the more complex functional groups of carboxylic acid derivatives. Functional groups which include a carbonyl are very widespread in the molecules of nature. An understanding, therefore, of how the carbonyl group reacts is essential for the study of biological chemistry as well as organic synthesis. These reactions are invariably with nucleophiles at the carbon atom, as expected of a functional group with the polarity represented by the partial structure, although complexation of an electrophile by a lone pair on the oxygen sometimes leads to electrophile catalysis.
Scale-up issues
Authors: Lee Stan , Robinson Graham
Published: September 2023

This chapter describes fine chemicals as organic compounds that are made in relatively small quantities and can be either intermediates towards a more complicated molecule or the final effect chemical. It explains why fine chemicals are usually made in general-purpose equipment. It also points out that the small quantities of the compound required for initial evaluation studies can often be produced in laboratory glassware and by use of suitably large glass vessels. The chapter emphasizes the limit to using larger glass vessels for larger quantities as glass is a relatively weak material that is prone to cracking during heating and cooling operations. It highlights the use of some form of metal plant that is achieved by use of reactors that are fabricated out of steel and lined with glass.
Fun with cephalosporins
Authors: Lee Stan , Robinson Graham
Published: September 2023

This chapter looks at process development chemists who, once they had become used to working with stable aromatic heterocycles, soon realized that cephalosporins have to be treated differently. This is because products containing the β-lactam ring are relatively unstable and reactions involving them are preferably carried out in organic solvents with heat avoided. In aqueous systems, processes are confined to a narrow pH range because extremes of pH cause rapid decomposition. The chapter highlights a specific method for measuring product purity or strength that must be devised as quickly as possible. It explains the definition of strength as the proportion of desired component in a sample that is usually expressed as %w/w.
Reagents for large-scale operation
Authors: Lee Stan , Robinson Graham
Published: September 2023

This chapter discusses how to determine which reagent to use for large-scale operations. This is governed by many factors in addition to yield and selectivity, including cost, availability, ease of disposal of residues, safety, reaction conditions, and solvent capability. The chapter suggests using a single solvent for chemical reactions whenever possible as this facilitates the charging of the solvent to the reactor and simplifies the operations if recovery and reuse are to be considered. It then summarizes the characteristics of a variety of solvents, oxidants, reducing agents, acids and bases, halogenation reagents, alkylating agents, enzymes, sulfur reagents, phosphorus reagents, boron reagents, silicon reagents, and palladium reagents. Their uses, advantages, and disadvantages are discussed to highlight that finding the best reagent often involves compromise.
Reactions of the anomeric centre Part II
Authors: Davis Benjamin G. , Fairbanks Antony J.
Published: September 2023

This chapter focuses on reactions that are particular to the anomeric centre of a free sugar which is hemiacetal and explains how the mechanisms by which nucleophilic substitution at the anomeric centre may occur. It describes the problem of control of stereochemistry at the anomeric centre and the use of neighbouring group participation. This allows for the formation of 1,2-trans glycosides. It also clarifies how to form anomeric bromides and illustrates their substitution reaction chemistry. The chapter discusses nucleophilic addition reactions to sugars which occur via the trapping of the free aldehyde and displacement of the ring opening equilibrium. It demonstrates the methods for extending or shortening the carbon chain of a sugar by one unit.
Reactions of hydroxyl groups Part II: cyclic acetals
Authors: Davis Benjamin G. , Fairbanks Antony J.
Published: September 2023

This chapter deals with the reactions of carbohydrate hydroxyl groups with other aldehydes and ketones to form cyclic acetals, which are utilized as a means of protecting particular sugar hydroxyl groups. It explains why the reaction of carbohydrates with acetone and acid produces cyclic 5-ring acetonides, whereas benzaldehyde and acid produce 6-ring benzylidenes. It also looks at the reaction of glucose with acetone and acid. This produces the pyranose diacetonide with only the 6-hydroxyl group free. The chapter then discusses the reaction of glucose with acetone and acid. This produces furanose diacetonide with 3-hydroxyl group free. It explains the protection of carbohydrates as butane diacetals. This results in selective protection of vicinal diequatorial diol groups.
Chemical glycobiology
Authors: Davis Benjamin G. , Fairbanks Antony J.
Published: September 2023

This chapter points out that carbohydrate science has the potential to foster further understanding and control of a range of biological processes. It explains the importance of D-glucose as a source of metabolic energy and provides an overview of the processes of D-glucose oxidation and how it leads to the formation of ATP. It also analyses fermentation, which is an alternative metabolic process found in yeast, and cites examples of structurally important polysaccharides. The chapter describes the structures and functions of glycoproteins and glycolipids and reviews the mechanism by which lectins are able to act as highly specific carbohydrate-binding proteins. It highlights key biological roles which carbohydrates play in inflammation and infection by microorganisms.
Oscillations, Waves, and Chaos in Chemical Kinetics
Authors: Scott Stephen K.
Published: September 2023

Oscillations, Waves, and Chaos in Chemical Kinetics shows how these ‘exotic’ patterns arise from the underlying chemical mechanisms. The phenomena of oscillations, travelling waves, and chaos in reacting chemical systems began as curiosities but now support an active, international research field. The origin of ‘chemical feedback’ is revealed using three example reactions: the iodate-reductant (Landolt) reaction, the Belousov–Zhabotinsky reaction, and the combustion of hydrogen. Thermal feedback is also discussed. These mechanisms lead to clock reactions and travelling reaction fronts, thermal runaway, and flames; to oscillations and excitability; to target patterns, spiral and scroll waves; to bistability, ignition, extinction, and hysteresis; and to complex oscillations and chaos in flow reactors. These phenomena are related to important processes in biology, including the development of cardiac arrhythmias, nerve signal transmission, and animal coat patterning.
Oscillatory reactions in flow systems
Authors: Scott Stephen K.
Published: September 2023

This chapter explores the gas-phase reaction between hydrogen and oxygen, which illustrates the influence of branched-chain kinetics on simple combustion reactions. It clarifies how chain branching provides feedback and is proven to be a classic nonlinear kinetic system. It also discusses p-Ta ignition limits in closed vessels, which are considered vessels of parametric sensitivity. The chapter describes two distinct modes of reaction that depend on the exact initial pressure and temperature: slow reaction and ignition. It points out that in slow reaction, the rate of conversion of reactants to the product H2O may be imperceptibly low, while in ignition the reaction proceeds on a millisecond timescale with explosive force and a considerable temperature excursion.
Essentials of Inorganic Chemistry 1
Authors: Mingos D.M.P.
Published: September 2023

Essentials of Inorganic Chemistry 1 starts off by examining acids and bases to the Aufbau principle. It then looks at back donation to the Born-Haber cycle. There are also chapters on canoncial and crystal structures, dative bond, dipole moment, effective atonomic number, and exchange energy. The text also covers Gibbs energy, halogens, hypervalent, inertness, lability, isometrism, and lanthanides. Other topics covered include magnetism, molecular orbital theory, inorganic compounds, polyhedral cage geometrics, resonance, and steric effects.
Acids and bases to Aufbar principle
Authors: Mingos D.M.P.
Published: September 2023

This chapter discusses acids and bases and the Aufbau principle. In the Brønsted definition, acids and bases function as proton donors and acceptors in a complementary manner. Compounds which are able to function both as Brønsted acids and bases are described as amphoteric. G.N. Lewis defined acids and bases in terms of electron-pair donation and acceptance. A base in an electron-pair donor and acid is an electron-pair acceptor. The chapter then looks at Lewis basicity trends, before considering actinides, alkali metals and alkaline earth metals, allotropy, the alternation effect, amorphous solids and anhydrous compounds, and aprotic solvent. The Aufbau principle states that the lowest energy (most stable) orbitals are occupied first and in a manner consistent with the Pauli exclusion principle, i.e. with two electrons with opposite spins in each singly degenerate orbital.
Effective atomic number rule to exchange energy
Authors: Mingos D.M.P.
Published: September 2023

This chapter assesses the effective atomic number rule. The effective atomic number rule applies to molecules where covalent bonding is strong and all the valence orbitals are being used in either homo- and hetero-polar covalent bonds or are occupied by non-binding electron-pairs. If the molecule is unable to achieve the octet or 18-electron configurations by virtue of donation from the ligands, then element–element bonds may be formed. The chapter then looks at electrode potential, before considering electron affinity and deficiency. The electron affinity is the negative of the electron capture enthalpy, while an electron deficient molecule has fewer valence electrons involved in covalent bonds than the number of orbitals available. The chapter also studies electronegativity, the electroneutrality principle, electropositivity, entropy, and exchange energy.
Gibbs energy
Authors: Mingos D.M.P.
Published: September 2023

This chapter addresses Gibbs energy, which is sometimes referred to as free energy, or as Gibbs free energy. Changes in Gibbs energy are more useful in chemistry because they determine whether reactions are energetically favourable. The second law of thermodynamics states that, in a spontaneous process, the change in entropy is equal to or greater than zero for the system and its surroundings. In the discussion of entropy, it was noted that it is important to distinguish in a chemical reaction that energy which is tied up in chemical bonds and that which is distributed amongst the translational, rotational, and vibrational degrees of freedom. For a spontaneous chemical process which leads to an enthalpy change, the corresponding change in the enthalpy of the surroundings is –∆H.
Terminal phosphine and bridging phosphido ligands
Authors: Housecraft Catherine E.
Published: September 2023

This chapter discusses the substitution of one or more carbonyl groups for other ligands and mentions large numbers of phosphine and phosphite derivatives of metal carbonyl dimers and clusters. It explains how related compounds that contain arsine and stibine ligands may be prepared by replacing terminal carbonyl groups. It also describes the important roles that steric and electronic requirements play in determining the site preferences and solid state structures of derivatives. The chapter refers to the reduction of steric crowding with the use of a didentate ligand in place of two monodentate ligands. It talks about the replacement of a carbonyl by a phosphine or phosphate ligand which is carried out by photolyzing or heating the two reagents in a solution.
Functional Groups
Authors: G. Denis Meakins
Published: September 2023

Functional Groups introduces reactions of functional groups in a concise and systematic form. It covers the characteristic properties of functional groups and the methods for interconverting them, which constitute important foundations of organic chemistry. Individual chapters cover organic halides, organometallic compounds, alkanes, alkenes, alkynes, aldehydes and ketons, carboxylic acids and derivatives, ethers, and amines.
Carboxylic acids and derivatives
Authors: G. Denis Meakins
Published: September 2023

This chapter discusses trends in general reactions, carboxylic acids, acyl chlorides and acid anhydrides, esters, and amides. It reviews the chemistry of carboxylic acids and their derivatives. This is mostly concerned with the attack of nucleophiles. It explains that acids generally do not react in this way because they have an acidic H, but after protonation they are prone to nucleophilic attack. The chapter also demonstrates a general reaction that consists of addition and elimination and refers to a stereoelectronic factor that favours the approach of the nucleophile at 90° to the carbonyl group. The chapter describes methanoic acid as unique in being a reducing agent and the strongest acid. Other acids are resistant to oxidation. It mentions the Schmidt reaction as something that is restricted to acids in which the R group is stable to strong mineral acid.
Alcohols 10 Ethers
Authors: G. Denis Meakins
Published: September 2023

This chapter describes a reaction concerned with sodium periodate and lead tetraacetate, which are useful reagents that have similar oxidizing properties. It demonstrates how salt NaIO4 is dissolved using an aqueous medium and how a covalent compound Pb(OAc)4 is soluble in some organic solvents and is decomposed by water. It highlights that the choice of reagent is determined by the solubility of the substrate. The chapter explains the difference in rates between cis cyclopentane-1,2-diol, which is the easy ring formation, and the trans isomer, which is the difficult ring formation. It covers reagents that cause fission of several other systems that have 1,2-oxygen-containing groups.
Photochemistry in nature
Authors: Wayne Carol E. , Wayne Richard P.
Published: September 2023

This chapter assesses some of the ways in which photochemistry has an impact on our lives. Natural photochemical phenomena have contributed to the evolution of life as we know it, and permit its continued existence on Earth. Indeed, photochemical reactions have performed a determining role in the evolution of the Earth's atmosphere. The forms and ecology of life that have been viable at any time in the past were directly dependent on the constitution of the atmosphere during that period. Photosynthesis is perhaps the most important of the many interesting photochemical processes known in biology. Not only was the evolution of the Earth's atmosphere dependent on it, but also animal life derives energy from the Sun, via photosynthesis, by eating plants. Meanwhile, vision is stimulated by the photochemical transformation of a pigment containing a moiety related to retinal, which is the aldehyde derived from vitamin A (retinol).
Effects on reactivity
Authors: Kirby A.J
Published: September 2023

This chapter evaluates the effects on reactivity. When two independent molecules collide in solution or in the gas phase, there is in principle no geometrical restriction on interactions between their orbitals, apart from any imposed by their intrinsic symmetries. Through-space interactions between two orbitals on the same molecule, on the other hand, are subject to the geometric constraints imposed by its structure. In the trivial case, we do not expect two groups to react with each other if they are on opposite faces of a rigid ring-system because the molecular geometry keeps them apart. Even when the groups concerned can get close, apparently within easy bond-forming distance, stereoelectronic effects may effectively prohibit reaction. Through-bond interactions also lead to many important reactions; these interactions are very clearly under stereoelectronic control.
Substitutions at saturated centres
Authors: Kirby A.J
Published: September 2023

This chapter focuses on substitutions at saturated centres. Substitution, or displacement, reactions are the commonest of all organic reactions, and substitutions at sp3-carbon were the first to be studied in depth. We know that two, conceptually quite different, mechanisms may be involved. The reaction can be concerted, with the new bond forming as the old bond breaks, or stepwise, with separate bond-breaking and bond-making steps. It can be a cation, as in the SN1 mechanism for nucleophilic substitution; an anion, in which case the reaction is electrophilic substitution; or a radical. The chapter then looks at concerted nucleophilic substitution; stereoelectronic barriers to intramolecular alkyl-group transfer; and the stabilization of the SN2 transition state by delocalization.
Introduction
Authors: Brouard M.
Published: September 2023

This introductory chapter provides an overview of elementary reactions in the gas phase. Most elementary reactions can be categorized as either unimolecular or bimolecular. Another class of reactions is association reactions. Association reactions and chemical activation can be modelled using the same theories as those developed to rationalize unimolecular reactions. The chapter then looks at reaction kinetics and dynamics, considering thermal rate coefficients and simple collision theory. It also offers some insight into the significance of the reaction cross-sections. Finally, the chapter highlights the role of the reaction probability on collision in determining the magnitude of the reaction cross-section and, hence, the thermal rate coefficient.
The differential cross-section
Authors: Brouard M.
Published: September 2023

This chapter examines the differential cross-section, which characterizes the scattering angle dependence of the collision or reaction cross-section. It begins by looking at elastic scattering. Non-reactive collisions may be categorized into those which conserve kinetic energy (elastic collisions) and those which do not (inelastic collisions). Inelastic collisions lead to the transfer of energy between translational and internal (electronic, vibrational, and rotational) degrees of freedom while elastic collisions merely transfer kinetic energy from one species to another. The chapter focuses on the latter process in order to introduce the important concepts of centrifugal kinetic energy and orbital angular momentum, which play a key role in chemical reactions. It then considers reactive scattering and stereochemistry.