Molecular Switches and Motors in 2‐D

Regular Arrays of Rod‐Shaped Molecular Photoswitches: Synthesis, Preparation, Characterization, and Selective Photoswitching within Mono‐ and Bilayer Systems

“…Representing a unique class of smart materials, regular two‐dimensional (2‐D) arrays made of stimuli‐responsive molecules can be used in a wide range of applications [1–6] . These arrays (or films) have been shown to modulate the physical properties of surfaces such as wettability, [7] surface tension, [8,9] adhesion, [10,11] and luminescence [12] .…”

“…These arrays (or films) have been shown to modulate the physical properties of surfaces such as wettability, [7] surface tension, [8,9] adhesion, [10,11] and luminescence [12] . The molecules that form these films usually consist of a photoswitch [13] connected by a linker to an anchoring group(s) [4] . These photoswitches are freely transferable between various surfaces.…”

“…However, the structures of the linkers and anchoring groups must be fine‐tuned to fulfill the specific needs of the individual substrates (e.g., metallic vs non‐metallic, solid vs liquid, etc.). Designing molecules of this kind is a challenging task that requires careful consideration of intermolecular spacing, the characteristics of the spacer and anchoring units, and the distance of the photoswitch from the surface [4] …”

“…The first approach, which applies to the vast majority of monolayers, involves self‐assembly on solid, predominantly metallic, surfaces. Crystalline gold (111) substrates are the most popular not only due to their compatibility with numerous analytical and spectroscopic techniques, but also because they can be handled outside a cleanroom environment [4,14] . Many sophisticated molecular platforms [15] and pedestals [16] have been developed to firmly anchor various molecular switches [17,18] or motors [7,19] .…”

Regular arrays of C60-based molecular rotors mounted on the surface of tris(o-phenylenedioxy)cyclotriphosphazene nanocrystals

“…Two-dimensional (2-D) regular arrays of functional molecules like rotors, motors and switches represent a unique class of stimuliresponsive materials with exciting properties. 1,2 They attract great attention due to their possible applications in sensing, 3,4 catalysis, 5 molecular machinery, 6,7 molecular electronics, 8,9 etc. The construction of such 2-D assemblies is surface-specific and usually requires properly designed molecules.…”