Host Guest Chemistry: Exploring Molecular Interactions and Their Role in Advanced Nanotechnology

Chapter 1: Host–guest chemistry

The term host–guest chemistry is used in the field of supramolecular chemistry to refer to complexes that are made up of two or more molecules or ions that are kept together in distinctive structural relationships by forces that are not the same as those that are associated with complete covalent bonds. The concept of molecular recognition and interactions through non-covalent bonding is that which is encompassed by the field of host–guest chemistry. In addition to being involved in a wide variety of biological processes that involve large molecules binding to one another in a specific but fleeting manner, non-covalent bonding is an essential component in the process of preserving the three-dimensional structure of large molecules like proteins.

Ionic bonding, hydrogen bonding, van der Waals forces, and hydrophobic interactions are the types of non-covalent interactions that are most frequently stated. Although non-covalent interactions could be generally split into those with greater electrostatic or dispersive contributions, there are just a few forms of non-covalent interactions that are commonly mentioned.

The interaction between the host and the guest has garnered a lot of attention ever since it was found. It is a significant field since the interaction between the host and the guest is necessary for a great number of biological processes, and it can be helpful in the design of certain materials. Cyclodextrin, crown ether, and other compounds are examples of typical host molecules. There are several other examples.

Host molecules typically have a structure that is pore-like and has the ability to capture guest molecules. Even though they are referred to be molecules, hosts and guests are frequently ions. The hydrophobic effect and van der Waals forces are two examples of the driving factors that could determine the outcome of the contact.

When there is a high degree of selectivity in the binding that occurs between the host and the guest, the interaction has been given the name molecular recognition. Frequently, a dynamic equilibrium exists between the states that are unbound and those that are bound:

Typically, the host component is the larger molecule, and it is the one that encloses the guest molecule, which is the smaller one. In the context of biological systems, the phrases host and guest are sometimes referred to as enzyme and substrate, respectively.

Inclusion compounds, which are often referred to as inclusion complexes, are closely associated with the chemistry of host–guest interactions.  In this case, a chemical complex is characterized by the presence of a cavity that can accommodate a guest component. The host chemical compound is the one that is being discussed.  There is no van der Waals bonding involved in the interaction that takes place between the host and the guest. The term inclusion compounds refers to a wide range of substances, including channels that are generated between molecules in a crystal lattice and that are sufficiently large to accommodate guest