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Chapter

Cover Pharmaceutical Chemistry

Inorganic Chemistry in Pharmacy  

Geoff Hall

This chapter analyzes individual inorganic elements that are organized into the alkali and alkaline earth metals, transition metals, zinc and iron, and the precious metals, silver, gold, and platinum, and the lanthanide metals. The non-metals studied here are phosphorus and sulfur. The chapter cites other elements which are important to drug development, drug action, and delivery. The chapter analyzes the chemical properties of an element and its biological function and refers to transition metal ions which are found in biological systems and precious metals which are found in drugs. It identifies various phosphorus and sulfur-containing functional groups in drug molecules and highlights the role of these functional groups for either the formulation of the drug into a medicine or the biological action of the drug.

Chapter

Cover Inorganic Chemistry in Biology

The d-block – nonredox chemistry  

This chapter discusses transition elements with a propensity for facile one or two electron changes that feature heavily in the oxidoreductases. It analyses the H2O liability that is essential for the metal ions to operate in metalloenzymes wherein the substitution of H2O by substrate is often a necessary step and is rarely rate limiting in the overall mechanism. It also explains how a substrate is added to the existing coordinated ligands, which is possible because the metal ions have variable coordination numbers. The chapter talks about the loss of liability when the metal ion is strongly chelated, which is required when the purpose of the ligand is to help transport the metal ion. It describes first row transition elements that are represented in the hydrolase, lyase, and isomerase classes.

Book

Cover Organometallics 1
Organometallics 1 outlines the main classes of transition metal organometallic complexes and introduces the reader to the chemistry of compounds with metal-carbon σ-bonds: metal carbonyls, metal alkyls, and metal alkylidenes and alkylidenes. The synthetic methods leading to each class of compounds are illustrated with pertinent examples, followed by the discussion of characteristic structures and reactivity patterns. The aim is to allow students a quick overview over this area of chemistry. Highlights and excursions stress general principles and relate the material to specific applications, such as catalytic processes.

Chapter

Cover Chemistry of the First-row Transition Metals

Compounds in lower oxidation states  

This chapter highlights the transition metal carbonyls which are useful and are easily available when starting materials for the synthesis of many other types of low-valent metal complexes. It examines the structures of the dinuclear and higher nuclearity species which feature bridging carbonyl groups and metal-metal bonds. It also discusses the number of electrons allocated to particular ligands for the purposes of electron counting. The chapter cites important exceptions to the 18-electron rule that are important in metal carbonyl and organometallic chemistry, such as the occurrence of stable compounds that have a formal 16-valence electron configuration. It reviews the thermodynamic stability of metal carbonyl derivatives that owes very little to the ability of CO to act as a Lewis base.

Chapter

Cover Inorganic Spectroscopic Methods

UV-visible spectroscopy  

This chapter evaluates UV–visible spectroscopy. Within inorganic chemistry, the field of study often associated with UV–visible spectroscopy is that of the coloured transition metal complexes. The energies associated with transitions between different arrangements of valence electrons falls within the ultraviolet (UV) and visible region of the electromagnetic spectrum. Just as the most popular form of vibrational spectroscopy is usually referred to by the region it occurs in—the infrared—so the most popular form of electronic spectroscopy is usually known as UV-visible spectroscopy and is in essence the study of the transitions involved in the rearrangements of valence electrons. The chapter then looks at metal–metal transitions, charge-transfer transitions, and ligand-centred transitions.

Chapter

Cover Organic Chemistry

Organometallic chemistry  

This chapter examines organometallic chemistry. It introduces the concepts of metal–ligand interaction, describes the most important reactions that can occur while ligands are bound to the metal, and demonstrates the power of organometallic chemistry in synthesis. The efficiency of transition metal-catalysed reactions means that they are routinely used in industrial synthesis. There is a simple guide to the stability of transition metal complexes: the 18-electron rule. If a complex satisfies the 18-electron rule it means that the metal at the centre of the complex has the noble gas configuration of 18-electrons in the valence shell, and the complex is likely to be stable. The chapter then considers that palladium is the most widely used metal in homogenous catalysis, before looking at the Heck reaction.

Book

Cover Biocoordination Chemistry
Biocoordination Chemistry introduces this field. The role of the transition metals in biological systems is of great interest to chemists: the chemical properties of these metals often define the biological function of the proteins and systems these metals are found in. This book introduces a number of topics: the transport and storage of metals, their functions in dioxygen interactions, electron-transfer, and enzyme activity; the therapeutic uses of coordination compounds; and the role that small-molecule models can play in advancing our knowledge of the structure and function of transition metals contained in metallobiosites.

Chapter

Cover The Mechanisms of Reactions at Transition Metal Sites

Substitution at four- coordinate sites  

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.

Book

Cover Chemical Structure and Reactivity
Chemical Structure and Reactivity is made up of two main parts. Part I covers the fundamentals and looks at molecules and molecular structures, electrons in atoms, symmetry, electrons in molecules, bonding in solids, thermodynamics, reactions, and organic chemistry. Part II delves deeper into the topics and examines spectroscopy, organic chemistry, transition metals, quantum mechanics and chemical thermodynamics, chemical kinetics, and electrochemistry.

Chapter

Cover Making the Transition to University Chemistry

Transition Metals 2  

This chapter focuses on the first row of transition metals ranging from tin to copper. It clarifies how scandium and zinc are not transition metals due to their oxidation states and d subshells. The group has d-block elements with at least one stable ion that has a partially-filled d subshell. Transition metals showcase variable oxidation states. An acidic solution with a reductant can reduce a transition metal ion, while an alkaline solution with an oxidant could oxidize a transition metal. The stability of the high oxidation states can be significantly increased in alkaline solutions. The chapter also notes how transition metals are often used as catalysts.

Chapter

Cover Chemical Structure and Reactivity

Transition metals  

This chapter assesses the d-block elements, which form Groups 3–11 and are collectively often referred to as the transition metals. The common feature of these elements is the presence of a partially filled d sub-shell. It is the presence of this partly filled shell which is responsible for most of the special properties which set the transition metals apart from main-group metals. These special properties include: the existence of compounds in which a particular element shows a range of oxidation states; the presence of unpaired electrons associated with the metal; the formation of coloured compounds and solutions; the formation of a large number of complexes in which the metal is surrounded by typically between four and six electron-donating ligands; and the formation of organometallic complexes in which the ligands have π systems. The chapter focuses mainly on transition metal complexes.

Book

Cover Organometallics and Catalysis
Organometallics and Catalysis consists of three parts. Part I looks at the organometallic compounds of the main group elements. Part 2 focuses on the organometallic compounds of the transition metals. Part 3 examines homogeneous catalysis with organometallic transition metal complexes. There are also four appendices: the first one covers commonly used solvents and their properties; the second one, number and symmetry of infrared-active vibrations of metal-carbonyl complexes; and the other two appendices present answers to exercises and further readings.

Chapter

Cover Organometallics 1

A few basics  

This chapter provides an overview of organometallic compounds, which are defined as substances containing direct metal–carbon bonds. The variety of the organic moiety in such compounds is practically infinite, ranging from alkyl substituents to alkenes, alkynes, carbonyls, and aromatic and heterocyclic compounds. Although some organometallic compounds have been known for a long time, it is only in the last four or five decades that organometallic chemistry has come into its own and experienced tremendous growth, both at a fundamental level where our insight into the nature of chemical bonds has been broadened by a variety of bonding situations without precedence elsewhere, and in its economic impact, such as catalysis. It is with the transition metals that the full diversity of organometallic chemistry becomes apparent. The chapter then explains the 18-electron rule, which provides a simple 'rule-of-thumb' basis for the discussion of structure and bonding.

Book

Cover The Electronic Structure and Chemistry of Solids
The Electronic Structure and Chemistry of Solids shows how the electronic structures and properties of solids can be described in terms familiar to chemists. Recent years have seen a considerable growth of interest in chemical aspects of the electronic structure of solids. The first three chapters give a fairly elementary account of the topics. The later chapters present slightly more advanced aspects, including many topics of current research interest, such as metal-insulator transitions, low-dimensional solids and “molecular metals”, and the properties of surfaces. The discussion is illustrated by a wide variety of examples.

Chapter

Cover Electron Paramagnetic Resonance

Transition metal ions and inorganic radicals  

This chapter describes transition metal ions (TMI) as isolated dopants in a solid matrix that coordinates an organic ligand in a metal complex. It analyses the unpaired electron confined to metal-based d-orbitals. It also looks at the key difference between the electron paramagnetic resonance (EPR) spectra of TMIs compared to organic radicals, noting that EPR exhibit large anisotropic g values which are no longer close to ge . The chapter presents the EPR linewidths which are often larger compared to organic radicals due to the short relaxation times. It explains why low temperature measurements are required to lengthen the relaxation time sufficiently for EPR spectra to be observable.

Chapter

Cover Biophysical Techniques

Atomic and molecular orbitals, their energy states, and transitions  

The aim of this tutorial is to introduce ideas about the shapes and energies of the wave functions that describe the distribution of electrons in atoms and molecules. This is important for understanding many of the properties described elsewhere, especially Section 5, which is concerned...

Chapter

Cover Essentials of Inorganic Chemistry 2

Isolobal analogy  

This chapter assesses the isolobal analogy, which provides a very useful methodology for rationalizing the structures of polyhedral molecules having both main group and transition metal fragments. It highlights that the metal carbonyl fragments of the later transition metals, the dδorbitals, are not used. Therefore, they form a maximum of three out-pointing hybrids, which makes them analogous to the main group fragments. It also notes that the total number of valence electrons in these isolobal fragments differ by 10. Finally, the chapter explains that, since the isolobal analogy is clearly linked to the Effective Atomic Number Rule, it has to be modified and indeed in some cases abandoned for classes of complexes where the rule is inapplicable.

Book

Cover Magnetochemistry

A. F. Orchard

Magnetochemistry provides an introduction to this area of study, which is the study of the magnetic properties of materials. Magnetochemistry is of central importance in the study of transition-metal complexes, providing information on the chemical bonding in these molecules. This text provides an introductory survey of the magnetic properties of chemical compounds with a particular focus, later in the book, on paramagnets. It also illustrates the applications of both susceptibility measurements and EPR spectra in the characterization of electronic structures. The uses of ordered materials in magnetics technology are highlighted throughout.

Chapter

Cover Magnetochemistry

Paramagnetism – part II Compounds of the transition elements  

This chapter deals with transition metals. These form an enormous variety of compounds and display a remarkable diversity of magnetic properties. It looks at paramagnetic phases and subtle aspects of paramagnetic behaviour, which provides a rich source of information about electronic structure. It also recounts the crucial role of the contemplation of paramagnetic properties in the development of ideas concerning the electronic structures of transition metal compounds, which formed the basis of the ligand field theory. The chapter discusses the importance of magnetic measurements of susceptibility and the EPR spectrum in the characterization of a newly synthesized compound. It mentions the 5-fold degeneracy of the d-orbitals characteristic of spherical symmetry. This, it states, is unsustainable in compounds of the transition elements due to the discriminating effects of the ligand environment.

Chapter

Cover d-Block Chemistry

Introduction  

This chapter focuses on d-block elements, which are the forty elements contained in the four rows of ten columns in the periodic table and are identified as the transition metals. It discusses the term transition element or transition metal. The term transition element derives from early studies of periodicity, as shown by the Mendeleev periodic table of the elements. The chapter also addresses some aspects of f-block elements where it is useful to make comparisons with the d-block metals. The chapter emphasizes the chemistry of the d block metal compounds. This is central to diverse areas, including analytical chemistry, inorganic chemistry, organic synthesis, catalysis, and metal extraction. The chapter describes the first row d-block elements as biologically necessary trace elements.