A visible-light-driven molecular motor based on barbituric acid

Chemical Science, Journal Year: 2023, Volume and Issue: 14(32), P. 8458 - 8465

Published: Jan. 1, 2023

We present a class of visible-light-driven molecular motors based on barbituric acid. Due to serendipitous reactivity we observed during their synthesis, these possess tertiary stereogenic centre the upper half, characterised by hydroxy group. Using combination femto- and nanosecond transient absorption spectroscopy, dynamics simulations low-temperature

Language: Английский

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Serial Femtosecond Crystallography Reveals that Photoactivation in a Fluorescent Protein Proceeds via the Hula Twist Mechanism

Journal of the American Chemical Society, Journal Year: 2023, Volume and Issue: 145(29), P. 15796 - 15808

Published: July 7, 2023

Chromophore cis/trans photoisomerization is a fundamental process in chemistry and the activation of many photosensitive proteins. A major task understanding effect protein environment on efficiency direction this reaction compared to what observed gas solution phases. In study, we set out visualize hula twist (HT) mechanism fluorescent protein, which hypothesized be preferred spatially constrained binding pocket. We use chlorine substituent break twofold symmetry embedded phenolic group chromophore unambiguously identify HT primary photoproduct. Through serial femtosecond crystallography, then track photoreaction from femtoseconds microsecond regime. observe signals for as early 300 fs, obtaining first experimental structural evidence its femtosecond-to-picosecond timescale. are able follow how isomerization twisting lead secondary structure rearrangements β-barrel across time window our measurements.

Language: Английский

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Excited State Dynamics in Unidirectional Photochemical Molecular Motors

Journal of the American Chemical Society, Journal Year: 2024, Volume and Issue: 146(18), P. 12255 - 12270

Published: April 24, 2024

Unidirectional photochemically driven molecular motors (PMMs) convert the energy of absorbed light into continuous rotational motion. As such they are key components in design machines. The prototypical and most widely employed class PMMs is overcrowded alkenes, where motion by successive photoisomerization thermal helix inversion steps. efficiency depends upon speed rotation, determined rate ground state inversion, quantum yield photoisomerization, which dependent on excited landscape. former has been optimized synthetic modification across three generations alkene PMMs. These improvements have often at expense yield, there remains room for improvement. In this perspective we review application ultrafast spectroscopy to characterize dynamics measurements lead a general mechanism all PMMs, involving subpicosecond decay Franck–Condon populate dark decays within picoseconds via conical intersections with electronic state. model discussed context calculations. Studies PMM photochemical as function solvent suggest exploitation intramolecular charge transfer polarity route controlling yield. A test these ideas first generation motor reveals high degree control over isomerization results pathway fine performance future

Language: Английский

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Machine learning photodynamics uncover blocked non-radiative mechanisms in aggregation-induced emission

Chem, Journal Year: 2024, Volume and Issue: 10(7), P. 2295 - 2310

Published: May 14, 2024

Language: Английский

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Machine learning accelerated photodynamics simulations

Chemical Physics Reviews, Journal Year: 2023, Volume and Issue: 4(3)

Published: Sept. 1, 2023

Machine learning (ML) continues to revolutionize computational chemistry for accelerating predictions and simulations by training on experimental or accurate but expensive quantum mechanical (QM) calculations. Photodynamics require hundreds of trajectories coupled with multiconfigurational QM calculations excited-state potential energies surfaces that contribute the prohibitive cost at long timescales complex organic molecules. ML accelerates photodynamics combining nonadiabatic an model trained high-fidelity energies, forces, non-adiabatic couplings. This approach has provided time-dependent molecular structural information understanding photochemical reaction mechanisms reactions in vacuum environments (i.e., explicit solvation). review focuses fundamentals techniques. We, then, discuss strategies balance adequate data generating these data. Finally, we demonstrate power applying ML-photodynamics understand origin reactivities selectivities reactions, such as cis–trans isomerization, [2 + 2]-cycloaddition, 4π-electrostatic ring-closing, hydrogen roaming mechanism.

Language: Английский

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On the description of conical intersections between excited electronic states with LR-TDDFT and ADC(2)

The Journal of Chemical Physics, Journal Year: 2023, Volume and Issue: 159(21)

Published: Dec. 7, 2023

Conical intersections constitute the conceptual bedrock of our working understanding ultrafast, nonadiabatic processes within photochemistry (and photophysics). Accurate calculation potential energy surfaces vicinity conical intersections, however, still poses a serious challenge to many popular electronic structure methods. Multiple works have reported on deficiency methods like linear-response time-dependent density functional theory adiabatic approximation (AA LR-TDDFT) or algebraic diagrammatic construction second-order [ADC(2)]-approaches often used in excited-state molecular dynamics simulations-to describe between ground and excited states. In present study, we focus attention states probe ability AA LR-TDDFT ADC(2) their topology topography, using protonated formaldimine pyrazine as two exemplar molecules. We also take opportunity revisit performance these describing involving state formaldimine-highlighting particular how intersection ring exhibited by can be perceived either (near-to-linear) seam interpenetrating cones, depending magnitude distortions branching space.

Language: Английский

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Picosecond quantum-classical dynamics reveals that the coexistence of light-induced microbial and animal chromophore rotary motion modulates the isomerization quantum yield of heliorhodopsin

Physical Chemistry Chemical Physics, Journal Year: 2024, Volume and Issue: 26(13), P. 10343 - 10356

Published: Jan. 1, 2024

Rhodopsins are light-responsive proteins forming two vast and evolutionary distinct superfamilies whose functions invariably triggered by the photoisomerization of a single retinal chromophore.

Language: Английский

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Multi-stimuli responsive smart materials: cyanine amphiphile self-assembly for photochromic and pH-switching applications

Materials Chemistry Frontiers, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 1, 2025

We designed the asymmetric cyanine amphiphile DPIIF, which exhibits reversible photochromism, pH responsiveness, and sol–gel transitions, offering potential applications in information security, anti-counterfeiting, biomedical studies.

Language: Английский

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Tuning the Photoisomerization Mechanism of Oxindole Switches with Electron-Donating Substituents

The Journal of Physical Chemistry B, Journal Year: 2025, Volume and Issue: unknown

Published: April 8, 2025

This study investigates the photoreaction mechanism of a hydroxy-substituted oxindole photoswitch using femtosecond transient absorption, fluorescence up-conversion, and computational chemistry. Deprotonation hydroxyl group enhances push-pull character in molecule, allowing tuning photoisomerization from precessional to an axial motion. The neutral form switch exhibits longer excited-state lifetimes, while anionic decays rapidly within 200 fs. Computational models show that deprotonation increases charge transfer accessibility conical intersections. work highlights how varying electron-donating strength substituent tunes designing photoswitches.

Language: Английский

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Exploring Exact-Factorization-Based Trajectories for Low-Energy Dynamics near a Conical Intersection

The Journal of Physical Chemistry A, Journal Year: 2024, Volume and Issue: 128(18), P. 3672 - 3684

Published: April 25, 2024

We study low-energy dynamics generated by a two-dimensional two-state Jahn-Teller Hamiltonian in the vicinity of conical intersection using quantum wave packet and trajectory dynamics. Recently, these were studied comparing adiabatic representation exact factorization, with purpose to highlight different nature topological-phase geometric-phase effects arising two theoretical representations same problem. Here, we employ factorization understand how accurately model an approximate description nuclear motion that uses trajectories. find since nonadiabatic are weak but non-negligible, trajectory-based invokes classical approximation struggles capture correct behavior.

Language: Английский

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