Physical chemistry

  • Article
    | Open Access

    Polycyclic aromatic hydrocarbons play an important role in interstellar chemistry, where interaction with high energy photons can induce ionization and fragmentation reactions. Here the authors, with XUV-IR pump-probe experiments, investigate the ultrafast photoinduced dynamics of fluorene, phenanthrene and pyrene, providing insight into their preferred reaction channels.

    • J. W. L. Lee
    • , D. S. Tikhonov
    •  & M. Schnell
  • Article
    | Open Access

    Identifying a concerted or stepwise mechanism in Diels–Alder reactions is experimentally challenging. Here the authors demonstrate the coexistence of both mechanisms in the reaction of 2,3-dibromobuta-1,3-diene with propene ions, using a conformationally controlled molecular beam reacting with trapped ions and ab initio computations

    • Ardita Kilaj
    • , Jia Wang
    •  & Stefan Willitsch
  • Article
    | Open Access

    Molecular chaperones from the Hsp70 family can break up protein aggregates, including amyloids. Here, the authors utilize microfluidic diffusional sizing to assess the mechanism of α-synuclein (αS) disaggregation by the Hsc70–DnaJB1–Apg2 system, and show that single αS molecules are removed directly from the fibril ends.

    • Matthias M. Schneider
    • , Saurabh Gautam
    •  & Tuomas P. J. Knowles
  • Article
    | Open Access

    Creating atomically-precise quantum architectures with high digital fidelity and desired quantum states is an important goal for quantum technology applications. Here the authors devise an on-surface synthetic protocol to construct atomically-precise covalently linked organic quantum corrals with the formation of a series of new quantum resonance states.

    • Xinnan Peng
    • , Harshitra Mahalingam
    •  & Jiong Lu
  • Article
    | Open Access

    Aqueous solutions under nanoscale confinement exhibit interesting physicochemical properties. This work reports evidence on the spontaneous formation of two-dimensional alkali chloride crystalline/non-crystalline nanostructures in dilute aqueous solution under nanoscale confinement by computer simulations.

    • Wenhui Zhao
    • , Yunxiang Sun
    •  & Xiao Cheng Zeng
  • Article
    | Open Access

    High-nitrogen content polyhedral molecules are of fundamental interest for theory and for synthesis applications. The authors, using isomer selective, tunable soft photoionization reflectron time-of-flight mass spectrometry, identify the formation of a hitherto elusive prismatic P3N3 molecule during sublimation of PH3 and N2 ice mixtures exposed to energetic electrons.

    • Cheng Zhu
    • , André K. Eckhardt
    •  & Ralf I. Kaiser
  • Article
    | Open Access

    Ultrafast diffraction is fundamental in capturing the structural dynamics of molecules. Here, the authors establish a variant of quantum state tomography for arbitrary degrees of freedom to characterize the molecular quantum states, which will enable the reconstruction of a quantum molecular movie from diffraction data.

    • Ming Zhang
    • , Shuqiao Zhang
    •  & Zheng Li
  • Article
    | Open Access

    Commonly, large π-conjugated systems facilitate low-energy electronic transitions. Here, the authors demonstrate that the relief of excited-state antiaromaticity of the benzene core leads to large Stokes shifts, and allows the construction of emitters covering the entire visible spectrum without the need of extending π-conjugation.

    • Heechan Kim
    • , Woojin Park
    •  & Dongwhan Lee
  • Article
    | Open Access

    Here, the authors use solid-state NMR and EPR measurements to characterise the ATP hydrolysis transition state of the oligomeric bacterial DnaB helicase from Helicobacter pylori, which was trapped by using aluminium fluoride as a chemical mimic. They identify protein protons that coordinate to the phosphate groups of ADP and DNA and observe that the aluminium fluoride unit is highly mobile and fast-rotating.

    • Alexander A. Malär
    • , Nino Wili
    •  & Thomas Wiegand
  • Article
    | Open Access

    The analysis of NMR spectra of complex biochemical samples with respect to individual resonances is challenging but critically important. Here, the authors present a deep learning-based method that accelerates this process also for crowded NMR data that are non-trivial to analyze, even by expert NMR spectroscopists.

    • Da-Wei Li
    • , Alexandar L. Hansen
    •  & Rafael Brüschweiler
  • Article
    | Open Access

    Shock-wave driven reactions of organic molecules may have played a key role in prebiotic chemistry, but their mechanisms are difficult to investigate. The authors, using time-resolved x-ray diffraction and small-angle x-ray scattering experiments, observe the transformation of liquid benzene during a shock, identifying carbon and hydrocarbon solid products.

    • D. M. Dattelbaum
    • , E. B. Watkins
    •  & R. L. Sandberg
  • Article
    | Open Access

    A complete understanding of singlet fission (SF) in molecular materials will enable the design of optimised optoelectronic devices. Here, the authors use vacancy control in acene-based blends to link coherent and incoherent SF pathways to energetics.

    • Clemens Zeiser
    • , Chad Cruz
    •  & Katharina Broch
  • Article
    | Open Access

    Radiationless relaxation is ubiquitous in natural processes and often involves excited states that are difficult to observe. Here the authors, combining X-ray transient absorption spectroscopy and computations, provide insight into the photoinduced dynamics in pyrazine and the involvement of an optically dark 1Au(nπ*) state.

    • Valeriu Scutelnic
    • , Shota Tsuru
    •  & Stephen R. Leone
  • Article
    | Open Access

    The roaming reaction is a common process in the gas phase and in solution, but observation of the involved atomic movements has been challenging. The authors, using femtosecond time-resolved X-ray liquidography, resolve the detailed structural dynamics at the onset of a roaming reaction in the photoinduced isomerization of BiI3 in solution.

    • Eun Hyuk Choi
    • , Jong Goo Kim
    •  & Hyotcherl Ihee
  • Article
    | Open Access

    Wear reduction in diamond-like carbon interacting with ZDDP-additivated oils is essential for current automotive applications. Here, the authors present an atomic-scale study revealing that this can be achieved by tailoring diamond-like carbon’s stiffness, surface nano-topography, and hydrogen content.

    • Valentin R. Salinas Ruiz
    • , Takuya Kuwahara
    •  & Maria-Isabel de Barros Bouchet
  • Article
    | Open Access

    The photodissociation dynamics of small molecules in the vacuum ultraviolet range can have key implications for astrochemical modelling, but revealing such dynamical details is a challenging task. Here the authors, combining high resolution experimental techniques, provide a detailed description of the fragmentation dynamics of selected rotational levels of a predissociated Rydberg state of H2S.

    • Yarui Zhao
    • , Zijie Luo
    •  & Xueming Yang
  • Article
    | Open Access

    Adsorption is a fundamentally important process but challenging to quantify, especially at the nanoscale. Here, the authors map the adsorption affinity and cooperativity of various ligands on single gold nanoparticles and discover adsorption crossover behaviors between different facets, leading to a strategy to control particle shape.

    • Rong Ye
    • , Ming Zhao
    •  & Peng Chen
  • Article
    | Open Access

    Reactions at the interface between mineral surfaces and flowing liquids are ubiquitous in nature. Here the authors explore, using surface-specific sum frequency generation spectroscopy and numeric calculations, how the liquid flow affects the charging and dissolution rates leading to flow-dependent charge gradients along the surface.

    • Patrick Ober
    • , Willem Q. Boon
    •  & Mischa Bonn
  • Article
    | Open Access

    Nuclear spin polarization and relaxation can be studied using nuclear magnetic resonance (NMR). Here the authors demonstrate a combination of fast-field cycling and optical magnetometry techniques, to realize a NMR sensor that operates in the region of very low frequency and high relaxation rate.

    • Sven Bodenstedt
    • , Morgan W. Mitchell
    •  & Michael C. D. Tayler
  • Article
    | Open Access

    Extension of nanostructure fabrication in the single-nm regime is a promising but fabrication of nanostructures with high aspect ratios remains challenging. Here, the authors use high energy charged particles to produce free-standing 1D organic nanostructures with extremely high aspect ratios and controlled number density.

    • Koshi Kamiya
    • , Kazuto Kayama
    •  & Shu Seki
  • Article
    | Open Access

    Quantum-mechanical methods of benchmark quality are widely used for describing molecular interactions. The present work shows that interaction energies by CCSD(T) and DMC are not in consistent agreement for a set of polarizable supramolecules calling for cooperative efforts solving this conundrum.

    • Yasmine S. Al-Hamdani
    • , Péter R. Nagy
    •  & Alexandre Tkatchenko
  • Article
    | Open Access

    The H3+ ion plays a key role in interstellar chemistry and can be formed from organic compounds upon interaction with charged particles or radiation. Here the authors demonstrate that H3+ can also be formed from water adsorbed on silica nanoparticles exposed to intense laser pulses, conditions that mimic the impact of charged particles on dust in astrophysical settings.

    • M. Said Alghabra
    • , Rami Ali
    •  & Ali S. Alnaser
  • Article
    | Open Access

    Active coacervate droplets are droplets coupled to a chemical reaction that maintains them out of equilibrium, which can be used to drive active processes, but coacervates are still subject to passive processes that compete with or mask growth. Here, the authors present a nucleotide-based model for active coacervate droplets that form and grow by fuel-driven synthesis of ATP, and, importantly, do not undergo Ostwald ripening.

    • Karina K. Nakashima
    • , Merlijn H. I. van Haren
    •  & Evan Spruijt
  • Article
    | Open Access

    Oxidative allylic C–H functionalizations minimise the need for functional group activation and generate alkenyl-substituted products amenable to further chemical modifications. Here the authors report an oxidant-free, electrocatalytic approach to achieve intramolecular oxidative allylic C–H amination and alkylation by employing tailored cobalt-salen complexes as catalysts.

    • Chen-Yan Cai
    • , Zheng-Jian Wu
    •  & Hai-Chao Xu
  • Article
    | Open Access

    Photon upconversion in lanthanide-doped nanoparticles enables important technological developments. Here the authors demonstrate a mechanism leading to enhanced upconversion emission in core-shell nanoparticles, and long-distance energy transfer between nanoparticles, through triplet state population of an organic surface ligand.

    • Sanyang Han
    • , Zhigao Yi
    •  & Xiaogang Liu
  • Article
    | Open Access

    Femtosecond time-resolved X-ray solution scattering (fs-TRXSS) measurements provide information on the structural dynamics of proteins in solution. Here, the authors present a structure refinement method for the analysis of fs-TRXSS data and use it to characterise the ultrafast structural changes of homodimeric haemoglobin.

    • Yunbeom Lee
    • , Jong Goo Kim
    •  & Hyotcherl Ihee
  • Article
    | Open Access

    Fluorogenic RNA aptamers such as Chili display strong fluorescence enhancement upon aptamer–ligand complex formation. Here, the authors provide insights into the mechanism of fluorescence activation of Chili by solving the crystal structures of Chili with its bound positively charged ligands DMHBO+ and DMHBI+, and they reveal that Chili uses an excited state proton transfer mechanism based on time-resolved optical spectroscopy measurements.

    • Mateusz Mieczkowski
    • , Christian Steinmetzger
    •  & Claudia Höbartner
  • Article
    | Open Access

    The subtle connections between water’s supercooled liquid and glassy states are difficult to characterize. Gartner et al. suggest with MD simulations that the long-range structure of glassy water may reflect signatures of water’s debated second critical point in the supercooled liquid.

    • Thomas E. Gartner III
    • , Salvatore Torquato
    •  & Pablo G. Debenedetti
  • Article
    | Open Access

    Realizing ultra-high work functions (UHWFs) in hole-doped polymer semiconductors remains a challenge due to water-oxidation reactions. Here, the authors determine the role of water-anion complexes in limiting the work function and develop a design strategy for realizing UHWF polymers.

    • Qi-Mian Koh
    • , Cindy Guanyu Tang
    •  & Peter K. H. Ho
  • Article
    | Open Access

    Vibrational energy transfer (VET) is essential for protein function as it is responsible for efficient energy dissipation in reaction sites and is linked to pathways of allosteric communication. Here authors equipped a tryptophan zipper with a VET injector and a VET sensor for femtosecond pump probe experiments to map the VET.

    • Erhan Deniz
    • , Luis Valiño-Borau
    •  & Jens Bredenbeck
  • Article
    | Open Access

    The use of room temperature exciton–polariton Bose–Einstein condensation is limited by the need for external high-finesse microcavities. The authors generate room temperature EPs with single-crystal microribbons as waveguide Fabry–Pérot microcavities, and demonstrate controllable output of coherent light.

    • Ji Tang
    • , Jian Zhang
    •  & Yong Sheng Zhao
  • Article
    | Open Access

    Water’s phase diagram exhibits several hydrogen-disordered phases which become ordered upon cooling, but the behavior of ice VI is still debated. The authors, using high-pressure neutron diffraction, identify structural distortions that transform ice VI into ice XIX, here identified as a hydrogen disordered phase.

    • Christoph G. Salzmann
    • , John S. Loveday
    •  & Craig L. Bull
  • Article
    | Open Access

    The dynamics of water molecules at interfaces controls natural and artificial processes, but experimental investigations have been challenging. Here the authors investigate water molecules on a graphene surface using helium spin-echo spectroscopy, and reveal a regime where freely mobile molecules undergo strong repulsive mutual interactions which inhibit ice nucleation.

    • Anton Tamtögl
    • , Emanuel Bahn
    •  & William Allison
  • Article
    | Open Access

    Predictive computational approaches are fundamental to accelerating solid-state inorganic synthesis. This work demonstrates a computational tractable approach constructed from available thermochemistry data and based on a graph-based network model for predicting solid-state inorganic reaction pathways.

    • Matthew J. McDermott
    • , Shyam S. Dwaraknath
    •  & Kristin A. Persson
  • Article
    | Open Access

    Raman optical activity (ROA) is useful for studying conformational structure and behavior of chiral molecules, but is limited by the weak signals. Here, the authors demonstrate 100x signal enhancement via an all-dielectric approach, using a silicon nanodisk array and exploiting its dark mode.

    • Ting-Hui Xiao
    • , Zhenzhou Cheng
    •  & Keisuke Goda
  • Article
    | Open Access

    UV-induced photodamage that likely occurred during the prebiotic synthesis of DNA and RNA is still an untackled issue for their origin on early Earth. Here, the authors show that substitution of 2,6-diaminopurine for adenine enables repair of cyclobutane pyrimidine dimers with high yields, and demonstrate that both 2,6-diaminopurine and adenine nucleosides can be formed under the same prebiotic conditions.

    • Rafał Szabla
    • , Magdalena Zdrowowicz
    •  & Janusz Rak
  • Article
    | Open Access

    So far, only a few chemical oscillators based on organic reactions have been developed. Here, the authors report both autocatalytic and oscillatory reaction networks that form substituted guanidines from thiouronium salts; when coupled to cascade cyclization, this reaction network produces oscillations in the production of pyrimidine-based heterocycles.

    • Alexander I. Novichkov
    • , Anton I. Hanopolskyi
    •  & Sergey N. Semenov
  • Article
    | Open Access

    The primary energy conversion step in photosynthesis, charge separation, takes place in the reaction center. Here the authors investigate the heliobacterial reaction center using multispectral two-dimensional electronic spectroscopy, identifying the primary electron acceptor and revealing the charge separation mechanism.

    • Yin Song
    • , Riley Sechrist
    •  & Jennifer P. Ogilvie
  • Article
    | Open Access

    Anisotropically functionalized colloids can serve as meso-atoms for self-assembly of new materials. Swinkels et al. extend the analogy with atomic scale counterparts and show how familiar ring opening and puckering emerges in alkane-like assemblies of tetraedric patchy particles.

    • P. J. M. Swinkels
    • , S. G. Stuij
    •  & P. Schall
  • Article
    | Open Access

    Furanose species have a key role in the chemistry of life despite their instability over pyranose ones. The authors, through NMR characterization of the anomeric ratios at equilibrium and a non-equilibrium theoretical treatment, show that a steady temperature gradient, at temperatures relevant to the early Earth, favors furanose over pyranose isomers.

    • Avinash Vicholous Dass
    • , Thomas Georgelin
    •  & Francesco Piazza
  • Article
    | Open Access

    The authors here propose a chemical reaction that forms ammoniated phyllosilicates on Ceres. This process could trigger at a very low temperature, suggesting Ceres evolution in a region different from its current location.

    • Santosh K. Singh
    • , Alexandre Bergantini
    •  & Ralf I. Kaiser
  • Article
    | Open Access

    The structure of water around Brønsted acid sites in zeolites is shown to influence their catalytic activity. Here the authors shed light on confinement effects in different pores zeolites/water interfaces acidic strength by means of ab-initio molecular dynamics and enhanced sampling metadynamics techniques.

    • Emanuele Grifoni
    • , GiovanniMaria Piccini
    •  & Michele Parrinello