What is the process called when different molecules associate or attach to each other?

The process of complexation refers to the interaction between different molecules that leads to the formation of a complex. This can involve a versatile range of molecules, including ions, ligands, and larger biomolecules. In complexation, one molecule (often a metal ion) binds to other molecules (ligands) through various types of chemical bonds, which can include coordinate covalent bonds or hydrogen bonds. This process is crucial in many biological and chemical systems, as it can affect solubility, reactivity, and biological activity of the compounds involved.

Understanding complexation is particularly important in fields such as pharmacology and biochemistry, where the interaction between drugs and biological tissues or proteins can significantly influence therapeutic outcomes. This distinguishes complexation from processes like enzyme induction, filtration, or absorption, which involve different mechanisms and functions unrelated to the association of distinct molecules.