Imine‐Functionalized Triazatriangulenium Platforms: Towards an Artificial Ciliated Epithelium

Abstract

Triazatriangulenium (TATA) platforms have been used to prepare highly ordered, self-assembled monolayers of free- and vertically standing imines on Au(111) surfaces. Upon irradiation, the imines undergo trans-cis isomerization and a fast thermal reaction (t1/2 =0.58 s at 20 °C) back to the more stable trans form. It is known that the photochemical reaction proceeds through rotation of the C=N bond and the thermochemical reaction through inversion at the N atom. The imine motors, therefore, should be able to induce a net displacement of particles above the surface similar to cilia epithelia in nature.

Exploring self‐organization of molecular tether molecules on a gold surface by global structure optimization

“…A central design idea of the TATA platforms with lateral alkyl chains was that by varying these chain lengths it should be possible to change the TATA–TATA distances in surface‐adsorbed TATA monolayers. This idea was expressed and repeated in all TATA papers and was seen as a welcome tool to control these TATA–TATA distances, to accommodate the spatial needs of different functionalities mounted at the TATA centers. However, only in a few of these papers, these TATA–TATA distances were systematically measured for several different chain lengths (by STM).…”

“…TATA platforms were investigated in many experimental studies, demonstrating the formation of regular superstructures on Au(111) with room‐temperature STM. Further work employed TATA platforms to mount photoswitchable molecules to surfaces. For this goal, some control over TATA–TATA distances is available by varying the lateral alkyl chain lengths.…”

Simulations of optically switchable molecular machines for particle transport

“…Upon irradiation with UV or visible light it translates a rather small E ↔ Z movement to a large amplitude motion of an alkene chain. To fix the cilia in space, they are mounted on a triazatriangulenium (TATA) platform which makes it possible to place them onto different kinds of surfaces where they form ordered monolayers confirmed by STM imaging experiments . In addition, the platform decouples the chromophore from any electronic interaction with the surface and allows guaranteed perpendicular alignment with respect to the surface.…”

“…Photoinduced switching on Au(111) surfaces was studied by IRRAS spectroscopy, surface plasmon resonance spectroscopy (SPR) including density functional theory (DFT) calculations and chronoamperometry . Further studies have showcased the versatility of the platform concept by introducing different chromophores, for example an imine or a porphyrine . Adding two TATA platforms to an azobenzene also allows for lateral mounting of chromophores to surfaces …”

Beyond “decorative” 2D supramolecular self-assembly: strategies towards functional surfaces for nanotechnology

“…The versatility of this approach was evidenced by immobilizing functional molecules such as azobenzenes and porphyrins. [46][47][48] The electronic decoupling of these systems was demonstrated by studying the photo-and thermally induced switching of azobenzene-functionalized TATA platforms, under ambient conditions. 49 The main result is that the azobenzenes mounted on platforms exhibit fast, reversible, and reproducible photoisomerization demonstrating that the electronic properties of the azobenzene functionality are preserved.…”