Abstract:The
design of a multicomponent system that aims at the direct visualization
of a synthetic rotary motor at the single molecule level on surfaces
is presented. The synthesis of two functional motors enabling photochemical
rotation and fluorescent detection is described. The light-driven
molecular motor is found to operate in the presence of a fluorescent
tag if a rigid long rod (32 Å) is installed between both photoactive
moieties. The photochemical isomerization and subsequent thermal helix
inversion steps are… Show more
“…Using sodium hydride as a base, the alcohol was alkylated to furnish propargyl ether 8 in excellent yield. Each of the compounds 5 – 8 displayed the typical 1 H nuclear magnetic resonance (NMR) splitting pattern that is observed for second-generation molecular motors with a related molecular structure 22 , 24 , 25 . Fig.…”
Section: Resultsmentioning
confidence: 97%
“…as a result of a pseudo-axial to pseudo-equatorial change in orientation (Supplementary Figs. 11 – 13 ) 25 . The thermal helix inversion of the unstable intermediates back to the stable motor configurations was effectuated by removing the irradiation source.…”
Molecular motors and switches change conformation under the influence of an external stimulus, e.g. light. They can be incorporated into functional systems, allowing the construction of adaptive materials and switchable catalysts. Here, we present two molecular motor-functionalized porphyrin macrocycles for future photo-switchable catalysis. They display helical, planar and point chirality, and are diastereomers, which differ in the relative orientation of the motor and macrocyclic components. Fluorescence, UV-vis, and 1H NMR experiments reveal that the motor-functionalized macrocycles can bind and thread different variants of viologen guests, including a one-side blocked polymeric one of 30 repeat units. The latter feature indicates that the motor systems can find the open end of a polymer chain, thread on it, and move along the chain to eventually bind at the viologen trap, opening possibilities for catalytic writing on single polymer chains via chemical routes.
“…Using sodium hydride as a base, the alcohol was alkylated to furnish propargyl ether 8 in excellent yield. Each of the compounds 5 – 8 displayed the typical 1 H nuclear magnetic resonance (NMR) splitting pattern that is observed for second-generation molecular motors with a related molecular structure 22 , 24 , 25 . Fig.…”
Section: Resultsmentioning
confidence: 97%
“…as a result of a pseudo-axial to pseudo-equatorial change in orientation (Supplementary Figs. 11 – 13 ) 25 . The thermal helix inversion of the unstable intermediates back to the stable motor configurations was effectuated by removing the irradiation source.…”
Molecular motors and switches change conformation under the influence of an external stimulus, e.g. light. They can be incorporated into functional systems, allowing the construction of adaptive materials and switchable catalysts. Here, we present two molecular motor-functionalized porphyrin macrocycles for future photo-switchable catalysis. They display helical, planar and point chirality, and are diastereomers, which differ in the relative orientation of the motor and macrocyclic components. Fluorescence, UV-vis, and 1H NMR experiments reveal that the motor-functionalized macrocycles can bind and thread different variants of viologen guests, including a one-side blocked polymeric one of 30 repeat units. The latter feature indicates that the motor systems can find the open end of a polymer chain, thread on it, and move along the chain to eventually bind at the viologen trap, opening possibilities for catalytic writing on single polymer chains via chemical routes.
“…UV‐visible studies imply that a 1 : 1 mixture of PBI‐ motor/stator in CH 2 Cl 2 irradiated for 2 h exhibit bathochromic shift suggests the formation of unstable isomer of motor which reverses to original form upon warming to room temperature. Thus, the design of motor/stator with multiple components point towards development of molecular machines …”
Section: Utilization Of External Stimuli Sourcesmentioning
Stimuli‐responsive materials have raised major attention in digital technology, sensors and biomedical applications owing to quick response towards external stimuli, for example light, voltage, pressure, temperature, mechanical friction and pH. Nevertheless, action of external stimuli on organic materials affects their internal physico‐chemical properties and facilitates improved thermal/photo stability, tuning detection sensitivity, accuracy and biocompatibility. This review article highlights recent progress on stimuli‐responsive materials with mixed valence species, viologens, twisting chirality, crystalline/amorphous, sol‐gel phase transitions and resulting supramolecular nanostructures via non‐covalent interactions. These materials can be applied in flexible electronics, drug delivery, detection of pollutants and bioimaging. Thus, the demand for widespread research on development of stimuli‐responsive materials are requisite to resolve the challenges pertaining to stability and sensitivity of devices for design in comprehensive technology.
“…Compared to tripodal anchors, only limited numbers of platforms with four contact sites are available . This is mainly due to the lack of suitable molecular structures with more than three arms that are arranged in a well‐defined spatial configuration for interfacial immobilization.…”
Section: Quadripodal Anchorsmentioning
confidence: 99%
“…Compared to tripodal anchors, only limited numberso fp latforms with four contacts ites are available. [64][65][66] This is mainly due to the lack of suitable moleculars tructures with more than three arms that are arranged in aw ell-defined spatial configuration for interfacial immobilization.S ome representative quadripodal anchors and the application of relatedf ilms and materialsa re discussed in this chapter.…”
The bottom‐up functionalization of solid surfaces shows increasing importance for a wide range of interdisciplinary applications. Multidentate anchors with more than two contact points can bind to solid surfaces with strong chemisorption, well‐defined upright configuration, and tailored functionality. The surface functionalization using multidentate anchors with three (tripodal), four (quadripodal), or more binding points is summarized herein, with a focus on those beyond classical tripodal anchors. In particular, the molecular design on how to achieve multisite interaction between anchor and substrate and the introduction of functional groups to thin films are discussed.
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