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.
Chapter
Introduction
Chapter
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.
Book
Manfred Bochmann
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
Introduction
This introductory chapter provides an overview of π-complexes, which are the complexes formed between metals and alkenes, alkynes, alkenyls, and arenes. This form of metal–carbon interaction is unique to transition metals. The moiety containing the π-bond may be neutral, such as ethene or ethyne, or formally anionic, as is the case with cyclopentadienyl or cyclo-octatetraenyl ligands. For transition metals, the 18-electron rule has a predictive function similar to the octet rule for main group elements. It provides a simple ‘rule-of-thumb’ basis for the discussion of structure and bonding, and although there are numerous exceptions, organometallic compounds which fulfil this rule tend to represent relative energy minima. In order to determine whether a compound obeys the 18-electron rule or not, it is useful to follow certain electron counting conventions. Ligands are classified according to the number of electrons they formally donate to the metal centre, following the covalent (electroneutral) counting convention.
Chapter
Alkene complexes
This chapter discusses alkene complexes. Alkene (olefin) complexes now exist of every transition metal and constitute one of the most important classes of coordination compounds. The development of the organometallic chemistry of olefins is closely connected with the rise of the petrochemical industry during the course of this century; olefins, in particular ethylene, are abundantly available from petrochemical feedstocks. The chapter then details the synthesis of alkene complexes and bonding of alkenes to transition metals. Olefins bind to transition metals via their π orbitals, by donating electron density into an empty metal d-orbital. However, since olefins are weak bases, the bond has to be stabilized by another bonding contribution: the donation of electron density from the metal to the olefin. Finally, the chapter explains the reactivity of alkene complexes.
Book
Organometallics 2 examines the interaction of transition metals with unsaturated molecules. This topic has led to fundamental insights in the nature of the chemical bond which, in turn, has provided the basis of important present-day applications such as transition metal mediated synthesis or homogeneous and heterogeneous catalysis. This book outlines the chemistry and discusses the bonding in of some of the most important classes of organometallic compounds: the complexes of transition metals with Pi-ligands such as alkenes, alkynes, arenes, and cyclopentadienyl and allyl ligands.
Chapter
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
James Keeler and Peter Wothers
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
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
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.
Book
David E. Fenton
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
d-Block elements
This chapter addresses the d block elements, which refers to the 30 elements contained in the 10 columns (3—12) in the periodic table. It includes the elements zinc, cadmium, and mercury, some properties of which it is logically appropriate to include in a discussion of transition metal chemistry. The term ‘transition metal’ is normally associated with those elements that possess a d sublevel that is partially filled with electrons in either its atom or a common oxidation state. Although d block metals are similar in many ways to those of the s and p-blocks, they have a much greater tendency to display variable oxidation states. The chapter then looks at transitional elements and coloured compounds, aqua complexes, and ligands. It also considers how standard electrode potentials may be used to predict the course of redox reactions, before studying catalytic action and outlining some important d block compounds.
Chapter
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.
