2. The fundamentals

‘The fundamentals’ investigates why the element carbon is so suited for the generation of so many compounds. Carbon has atomic number six, meaning it has six protons in its nucleus and six electrons around the nucleus, four of which are valence electrons held in the outer shell. Carbon achieves a stable, full outer shell of electrons by sharing electrons with other elements and other carbon atoms to form covalent bonds. The carbon–carbon bonds are one of the principle reasons why so many organic molecules are possible, including linear chains, branched chains, and rings. The naming of compounds and identification of structures is also explained along with stereochemistry, functional groups, and intermolecular and intramolecular interactions.

9. Nanochemistry

Nanochemistry involves the synthesis of molecular nanostructures measuring 1–100nm. These could serve as molecular components for nanorobots and other molecular devices that could be used in medicine, analysis, synthesis, electronics, data storage, or material science. ‘Nanochemistry’ describes the carbon allotropes of diamond, graphite (including the single-layer graphene), and fullerenes and looks at their properties and potential applications. It then considers nanotubes, which are useful in nanoelectronic circuitry as insulators, semiconductors, or conductors; rotaxanes and their potential as molecular switches; nanoparticles and nanostructures constructed from DNA; and examples of nanodevices and nanomachines. It ends with a discussion of the safety and toxicology issues of nanotechnology.

1. Introduction

Organic chemistry is the study of carbon-based compounds in terms of their structure, properties, and synthesis. One reason for considering organic chemistry as a specialist field is because of the vast numbers of different organic compounds that can be synthesized—far more than would be possible for any other element. For over a hundred years, organic chemists have contributed vastly to our understanding of life at the molecular level, and produced novel compounds that have revolutionized modern society. The Introduction explains that there have been many benefits, but also some drawbacks. New discoveries can produce problems that affect health and the environment if they are not used with due care and responsibility.

8. Polymers, plastics, and textiles

Over the last fifty years, synthetic materials have largely replaced natural materials such as wood, leather, wool, and cotton. Plastics and polymers are perhaps the most visible sign of how organic chemistry has changed society. ‘Polymers, plastics, and textiles’ explains that polymerization involves linking molecular building blocks (termed monomers) into long molecular strands called polymers and describes the two general approaches to preparing polymers: addition polymers and condensation polymers. The various health, environmental, ecological, and economic issues are considered before looking at the processes of recycling and depolymerization and recent efforts to develop biodegradable plastics and bioplastics. It ends with exciting new developments of new polymers with novel applications.

7. The chemistry of the senses

Naturally occurring organic molecules play an important role in the way we perceive the world through the senses of sight, taste, and smell. In addition, many synthetic organic molecules have been designed to have colour, taste, and scent, important for the food and cosmetic industries. ‘The chemistry of the senses’ considers the chemistry of vision, scent, and taste. It describes the naturally occurring 11-cis-retinal, crucial to the mechanism by which the rod cells in the human eye detect visible light, and looks at the scented molecules that interact with olfactory receptors in the nose. Finally, it explains how the sensation of taste is caused by organic molecules interacting with the tongue’s taste receptors.

5. Pharmaceuticals and medicinal chemistry

One of the most important applications of organic chemistry involves the design and synthesis of pharmaceutical agents—a topic defined as medicinal chemistry. ‘Pharmaceuticals and medicinal chemistry’ describes the pathfinder years of the 19th and 20th centuries before considering the development of rational drug design from the 1960s. It explains the identification of a drug target; how drug testing and bioassays work; the identification of lead compounds, structure activity relationships, and pharmacopores; and drug optimization. It outlines the processes of drug development through preclinical trials, clinical trials, and regulatory affairs. Finally, it looks to the future and outlines some of the challenges ahead as well as considering veterinary drugs and drugs of abuse.

4. The chemistry of life

From very simple molecular building blocks, life has created an astonishing diversity of molecules, some of which are extremely complex structures that prove very difficult to synthesize in a laboratory. ‘The chemistry of life’ describes how proteins, which serve a myriad of purposes, and nucleic acids, another form of biopolymer, are constructed from molecular building blocks called amino acids and nucleotides respectively. It goes on to explain the polymerization processes involved in the biosynthesis of many other natural products; the functions of proteins, DNA, and RNA; and the different theories proposed to explain chemical evolution, or prebiotic chemistry. Enzymes and nucleic acids are increasingly being used in commercial applications.

6. Pesticides

Pesticides are organic chemicals produced by the agrochemical industry to improve agricultural yields and to fight crop disease. They include insecticides, fungicides, and herbicides, which have proved vital in increasing food production for a global population that is expected to increase by 33 per cent over the next thirty-five years. ‘Pesticides’ explains that concerns over the effects of traditional pesticides have promoted research into designing safer and more environmentally friendly pesticides. It describes the research into different insecticides—organochlorine agents, methylcarbamates, organophosphates, pyrethrins, pyrethroids, and neonicotinoids—before considering the search for new insecticides, which act on a range of different targets as a means of tackling resistance, and looking at fungicides and herbicides in more detail.

3. The synthesis and analysis of organic compounds

The design of novel medicines, insecticides, perfumes, flavourings, or polymeric materials relies crucially on organic chemists. ‘The synthesis and analysis of organic compounds’ outlines how the synthesis of an organic compound is devised to ensure that each atom is in the correct position within the molecule. It explains retrosynthesis and how reactions are carried out and monitored using chromatography and infrared spectroscopy. Once a reaction has been carried out, it is necessary to isolate and purify the reaction product. The structure of the end product needs to be analysed by elemental analysis, mass spectrometry, X-ray crystallography, or nuclear magnetic resonance spectroscopy. Another important part of organic chemistry is understanding how reactions take place.