Molecular Networks and Surface Engineering for Single Molecule Studies: From Spatial Separation to Emergent Properties

Functional molecules, among them artificial rotors, motors or gears, have been extensively studied over the past two decades with the aim to incorporate them into nanoscale devices, machines or factories. A plethora of studies have been conducted on functional molecules within a 3D (solution) environment while their investigation on atomically flat 2D surfaces despite being often a laborious effort has proven to add important insight. A less studied, but nevertheless important aspect is the (engineered) environment in which they operate, such as within the pore of a molecular network. Here, we review studies on the confinement of functional molecules within (porous) host–guest networks on atomically flat surfaces and discuss the effects this has on the operation of the functional molecule in question. To this end we will also provide a brief introduction to host–guest chemistry on surfaces. We will also present other methods to spatially arrange functional molecules, for instance through the use of specially engineered pre-patterned surfaces. Lastly, we will pay attention to the use of self-assembled networks to study emergent behavior of functional molecules.