Design of Collective Motions from Synthetic Molecular Switches, Rotors, and Motors

Dattler, Damien; Fuks, Gad; Heiser, Joakim; Moulin, Émilie; Perrot, Alexis; Yao, Xin; Giuseppone, Nicolas

doi:10.1021/acs.chemrev.9b00288

Cited by 345 publications

(297 citation statements)

References 1,213 publications

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“…Noticeable applications range from classical supramolecular devices (recognition, self‐assembly, transport, sensing, catalysis, etc .) to photoresponsive architectures, passing through responsive materials and polymer science, energy‐related technologies, molecular machines, and biology . The preference for azobenzene with respect to other molecular switches relays on its easy preparation and functionalization, on the neat photophysical behavior that normally allows fast E / Z isomerization and selective irradiation of the two isomers, and on the large geometrical rearrangement that accompanies the isomerization process .…”

Section: Introductionmentioning

confidence: 97%

Configurational Selection in Azobenzene‐Based Supramolecular Systems Through Dual‐Stimuli Processes

Tecilla

Bonifazi

2020

ChemistryOpen

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Azobenzene is one of the most studied light-controlled molecular switches and it has been incorporated in a large variety of supramolecular systems to control their structural and functional properties. Given the peculiar isomeric distribution at the photoexcited state (PSS), azobenzene derivatives have been used as photoactive framework to build metastable supramolecular systems that are out of the thermodynamic equilibrium. This could be achieved exploiting the peculiar E/Z photoisomerization process that can lead to isomeric ratios that are unreachable in thermal equilibrium conditions. The challenge in the field is to find molecular architectures that, under given external circumstances, lead to a given isomeric ratio in a reversible and predictable manner, ensuring an ultimate control of the configurational distribution and system composition. By reviewing early and recent works in the field, this review aims at describing photoswitchable systems that, containing an azobenzene dye, display a controlled configurational equilibrium by means of a molecular recognition event. Specifically, examples include programmed photoactive molecular architectures binding cations, anions and H-bonded neutral guests. In these systems the non-covalent molecular recognition adds onto the thermal and light stimuli, equipping the supramolecular architecture with an additional external trigger to select the desired configuration composition.[a] Prof. P. Tecilla

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Section: Introductionmentioning

confidence: 97%

Configurational Selection in Azobenzene‐Based Supramolecular Systems Through Dual‐Stimuli Processes

Tecilla

Bonifazi

2020

ChemistryOpen

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“…However, in a number of other cases, we have seen that the extraction and the transfer of the mechanical nanoactuation from the machine toward mechanical actuations at higher length scales are possible. This original aspect features a “hierarchical mechanics”, which is particularly novel in terms of materials design, and which can give access in principle to new properties and functions …”

Section: Discussionmentioning

confidence: 99%

From Molecular Machines to Stimuli‐Responsive Materials

et al. 2019

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Shape-memory effects and mechanical actuations can be indeed generated from objects of various chemical nature [3][4][5] (e.g., metallic alloys, ceramics, liquid crystals, or polymers), and they are often supported by a combination of bottom-up and top-down structural engineering techniques going from surfaces to 3D materials (e.g., supramolecular self-assembly, photopatterning, microfluidics, or inkjet printing). [6,7] Various stimuli can generate their response (e.g., molecules, temperature, light, electrical potential, or mechanical stress) and their functioning principles vary largely from one system to another, involving a number of physical phenomena which can take place at the (macro)molecular level and which are transferred toward higher length scales (e.g., polarity, solubility-such as lower critical solution temperature (LCST), osmotic pressure, surface energy, or phase transition). It should also be mentioned that bio-inspiration is often a driving force in the design of such artificial materials as many smart mechano-active systems with adaptable properties are found in nature (e.g., stiffness change of sea cucumber, adaptive toughness of spider silk, closure of mimosa leaves when touched, or opening of seed pods). [8][9][10] Since the early 2000s, exciting opportunities have emerged in the scientific community for making use of artificial molecular machines as the elementary responsive building blocks in new types of stimuli-responsive materials. This approach is fundamentally disruptive compared to the others developed so far, because it aims to exploit precisely controlled mechanical motions at molecular level (produced by the machines), and to amplify them in collective mechanical motions taking place at larger dimensions up to the material's length scale. The most prominent example of what could be potentially achieved in the far future by such artificial materials is also found in nature, in the form of striated muscle tissue. In muscles, by using adenosine triphosphate (ATP) as chemical fuel, millions of myosin motors, which individually cycle hundreds of few nanometers scale actuations, are able to pull synchronously on sliding actin filaments and to produce micrometric contractions of sarcomeric units. Further hierarchical organizations of sarcomeres in bundled fibrils and fibers result in a macroscopic contraction of the muscle. At that point, and before describing selected examples of (much simpler) artificial systems, it is important for the readers who would not be familiar with molecular machines to first introduce more precisely terms and notions which define their nature and actuation principles. Artificial molecular machines are able to produce and exploit precise nanoscale actuations in response to chemical or physical triggers. Recent scientific efforts have been devoted to the integration, orientation, and interfacing of large assemblies of molecular machines in order to harness their collective actuations at larger length scale and up to the generation of macroscopic motions. Maki...

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“…In recent decades, the goal of creating artificial molecule-scale mechanical systems (e.g., molecular machines, shuttles, gears, rotors, turnstiles) has attracted enormous attention within the synthetic community [1,2]. Herein, we focus on one specifically selected approach-transition metal catalysed coupling [3], towards the synthesis of the "skeletal backbones" of molecular mechanical systems, their basic construction elements.…”

Section: Introductionmentioning

confidence: 99%

Palladium-Catalysed Coupling Reactions En Route to Molecular Machines: Sterically Hindered Indenyl and Ferrocenyl Anthracenes and Triptycenes, and Biindenyls

McGlinchey

Nikitin

2020

Molecules

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Pd-catalysed Stille and Suzuki cross-couplings were used to prepare 9-(3-indenyl)-, 6, and 9-(2-indenyl)-anthracene, 7; addition of benzyne led to the 9-Indenyl-triptycenes, 8 and 9. In 6, [4 + 2] addition also occurred to the indenyl substituent. Reaction of 6 through 9 with Cr(CO)6 or Re2(CO)10 gave their M(CO)3 derivatives, where the Cr or Re was complexed to a six- or five-membered ring, respectively. In the 9-(2-indenyl)triptycene complexes, slowed rotation of the paddlewheel on the NMR time-scale was apparent in the η5-Re(CO)3 case and, when the η6-Cr(CO)3 was deprotonated, the resulting haptotropic shift of the metal tripod onto the five-membered ring also blocked paddlewheel rotation, thus functioning as an organometallic molecular brake. Suzuki coupling of ferrocenylboronic acid to mono- or dibromoanthracene yielded the ferrocenyl anthracenes en route to the corresponding triptycenes in which stepwise hindered rotations of the ferrocenyl groups behaved like molecular dials. CuCl2-mediated coupling of methyl- and phenyl-indenes yielded their rac and meso 2,2′-biindenyls; surprisingly, however, the apparently sterically crowded rac 2,2′-Bis(9-triptycyl)biindenyl functioned as a freely rotating set of molecular gears. The predicted high rotation barrier in 9-phenylanthracene was experimentally validated via the Pd-catalysed syntheses of di(3-fluorophenyl)anthracene and 9-(1-naphthyl)-10-phenylanthracene.

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Design of Collective Motions from Synthetic Molecular Switches, Rotors, and Motors

Cited by 345 publications

References 1,213 publications

Configurational Selection in Azobenzene‐Based Supramolecular Systems Through Dual‐Stimuli Processes

Configurational Selection in Azobenzene‐Based Supramolecular Systems Through Dual‐Stimuli Processes

From Molecular Machines to Stimuli‐Responsive Materials

Palladium-Catalysed Coupling Reactions En Route to Molecular Machines: Sterically Hindered Indenyl and Ferrocenyl Anthracenes and Triptycenes, and Biindenyls

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