Individual‐Molecule Perspective Analysis of Chemical Reaction Networks: The Case of a Light‐Driven Supramolecular Pump

Sabatino, Andrea; Penocchio, Emanuele; Ragazzon, Giulio; Credi, Alberto; Frezzato, Diego

doi:10.1002/anie.201908026

Cited by 38 publications

(45 citation statements)

References 38 publications

(77 reference statements)

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“…The latter consist of a secondary ammonium moiety as a recognition site for the ring, [11] positioned between a photoswitchable azobenzene gate and a non‐photoactive cyclopentyl pseudostopper. The previously studied molecular pump[ 8a , 8c ] comprised axle 2 a and 2,3‐dinaphtho[24]crown‐8, whose fluorescent naphthalene moieties were instrumental in the determination of the ring concentration. In the present study we do not rely on luminescence measurements; thus, we employed dibenzo[24]crown‐8, which has a cavity of the same size as that of the previously used dinaphtho crown ether and is commercially available.…”

Section: Resultsmentioning

confidence: 99%

Artificial Supramolecular Pumps Powered by Light

Corrà

Casimiro

Baroncini

et al. 2021

Chemistry A European J

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The development of artificial nanoscale motors that can use energy from a source to perform tasks requires systems capable of performing directionally controlled molecular movements and operating away from chemical equilibrium. Here, the design, synthesis and properties of pseudorotaxanes are described, in which a photon input triggers the unidirectional motion of a macrocyclic ring with respect to a non-symmetric molecular axle. The photoinduced energy ratcheting at the basis of the pumping mechanism is validated by measuring the relevant thermodynamic and kinetic parameters. Owing to the photochemical behavior of the azobenzene moiety embedded in the axle, the pump can repeat its operation cycle autonomously under continuous illumination. NMR spectroscopy was used to observe the dissipative non-equilibrium state generated in situ by light irradiation. We also show that fine changes in the axle structure lead to an improvement in the performance of the motor. Such results highlight the modularity and versatility of this minimalist pump design, which provides facile access to dynamic systems that operate under photoinduced nonequilibrium regimes.

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Section: Resultsmentioning

confidence: 99%

Artificial Supramolecular Pumps Powered by Light

Corrà

Casimiro

Baroncini

et al. 2021

Chemistry A European J

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“…The knowledge will help designing and regulating allosteric molecular machines [25] (sequesters, catalysts, etc.) akin to those in nature [26] and for which the order by which chemical events take place is important [27] …”

Section: Discussionmentioning

confidence: 99%

From Selection to Instruction and Back: Competing Conformational Selection and Induced Fit Pathways in Abiotic Hosts

et al. 2021

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Two limiting cases of molecular recognition, induced fit (IF) and conformational selection (CS), play a central role in allosteric regulation of natural systems. The IF paradigm states that a substrate “instructs” the host to change its shape after complexation, while CS asserts that a guest “selects” the optimal fit from an ensemble of preexisting host conformations. With no studies that quantitatively address the interplay of two limiting pathways in abiotic systems, we herein and for the first time describe the way by which twisted capsule M‐1, encompassing two conformers M‐1(+) and M‐1(−), trap CX4 (X=Cl, Br) to give CX4⊂M‐1(+) and CX4⊂M‐1(−), with all four states being in thermal equilibrium. With the assistance of 2D EXSY, we found that CBr4 would, at its lower concentrations, bind M‐1 via a M‐1(+)→M‐1(−)→CBr4⊂M‐1(−) pathway corresponding to conformational selection. For M‐1 complexing CCl4 though, data from 2D EXSY measurements and 1D NMR line‐shape analysis suggested that lower CCl4 concentrations would favor CS while the IF pathway prevailed at higher proportions of the guest. Since CS and IF are not mutually exclusive, we reason that our work sets the stage for characterizing the dynamics of a wide range of already existing hosts to broaden our fundamental understanding of their action. The objective is to master the way in which encapsulation takes place for designing novel and allosteric sequestering agents, catalysts and chemosensors akin to those found in nature.

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“…This work lays the basis for quantitative energetic considerations in light-powered chemical systems. A direct application could be to evaluate the thermodynamic efficiency of light-driven molecular motors, whose performance has been assessed just from a dynamical standpoint [61,62]. In the long run, our results pave the way for a unified thermodynamic perspective on free-energy transduction from different sources (e.g.…”

Section: Introductionmentioning

confidence: 92%

Nonequilibrium thermodynamics of light-induced reactions

Penocchio,

Rao,

Esposito

2021

Preprint

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Current formulations of nonequilibrium thermodynamics of open chemical reaction networks only consider chemostats as free-energy sources sustaining nonequilibrium behaviours. Here, we extend the theory to include incoherent light as a source of free energy. We do so by relying on a local equilibrium assumption to derive the chemical potential of photons relative to the system they interact with. This allows us to identify the thermodynamic potential and the thermodynamic forces driving light-reacting chemical systems out of equilibrium. We use this framework to treat two paradigmatic photochemical mechanisms describing light-induced unimolecular reactions -namely the adiabatic and diabatic mechanisms -and highlight the different thermodynamics they lead to. Furthermore, using a thermodynamic coarse-graining procedure, we express our findings in terms of commonly measured experimental quantities such as quantum yields.

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Individual‐Molecule Perspective Analysis of Chemical Reaction Networks: The Case of a Light‐Driven Supramolecular Pump

Cited by 38 publications

References 38 publications

Artificial Supramolecular Pumps Powered by Light

Artificial Supramolecular Pumps Powered by Light

From Selection to Instruction and Back: Competing Conformational Selection and Induced Fit Pathways in Abiotic Hosts

Nonequilibrium thermodynamics of light-induced reactions

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