Search Results

This review discusses the potential of metal-based compounds to act as safe and affordable drugs in the treatment of important tropical parasitic illnesses such as Chagas disease, leishmaniasis, and malaria. Currently, half the world’s population is estimated to be at risk of contracting these vector-borne diseases, and almost one million people die annually from these diseases. No effective vaccine exists to treat these infectious diseases and available treatments are far from ideal. Coordination metal complexes offer potential in the development of new antiparasitic drugs. Indeed, coordination compounds in medicine are a growing and exciting research field, having been used successfully in cancer therapy. As an antiparasitic agent, ferroquine has entered phase II clinical trials against malaria and is an excellent example to encourage the development of antiparasitic metal-based drugs. Insights into the mechanism of actions of metal-based antiparasitic drugs are discussed.

This overview covers the role of the metal ions in infectious diseases, focusing on iron, copper, zinc, and, to a lesser extent, manganese and the metalloid selenium. Recommended dietary allowances are addressed, as are metal-based drugs for the treatment of tropical diseases. The human organism binds essential metals such as iron, manganese, copper, and zinc to specific compounds (including proteins) in order to withhold these metals from invading pathogens (“nutritional immunity”); in this way, metal binding provides resistance to infection. Selenium status can also affect the host–pathogen interaction, but pathogens have mechanisms to counteract this protective potency. Due to the epidemic proportions of tropical diseases and lack of effective treatment, drugs are being developed that are based on coordination compounds of metals, including copper, iron, ruthenium, and gold. These metals are coordinated to aromatic ligand systems which allow drug stabilization, during the drug’s transport to its target, and eventually intercalation into DNA. For malaria, the increasing resistance of the malaria parasite against the classical drug chloroquine may be overcome by employing ferrocenyl derivatives of chloroquine.

This chapter reviews some useful notions that are needed to understand the electronic structure of molecules. It first discusses the basic aspects of molecular orbital theory and how symmetry may be used to simplify the problem of defining the molecular orbitals by using group theory. The usefulness of these basic group theory notions are illustrated by considering the example of cyclobutadiene. Finally, the chapter looks at some general aspects of the electronic structure of transition metal coordination complexes.

This chapter examines theoretical advances in understanding molecular structures at the turn of the 20th century which resulted from the Blomstrand-Jørgensen/Werner debate about the structure of cobalt complexes. Both models made predictions testable through precipitation experiments, which eventually led to Werner’s model replacing the Blomstrand-Jørgensen model of cobalt complexes. We argue that this example of theory change fits within a selective scientific realist framework: namely, the factors which gave rise to the predictive success of the failed model survived in the theory that replaced it. We further argue that the lessons from this historical case can illuminate how two contemporary objections to realism—P. Kyle Stanford’s Problem of Unconceived Alternatives and Timothy D. Lyons’ pessimistic modus tollens argument—fall short as arguments against realism.