Takayuki Nakamuro

Crystallization is the process of atoms or molecules forming an organized solid via nucleation and growth. Being intrinsically stochastic, the research at an atomistic level has been a huge experimental challenge. We report herein in situ detection of a crystal nucleus forming during nucleation/growth of a NaCl nanocrystal, as video recorded in the interior of a vibrating conical carbon nanotube at 20-40 ms frame^-1 with localization precision of <0.1 nm. We saw NaCl units assembled to

Sulfonylation of 1H-tetrazoles with triflic anhydride in the presence of chiral rhodium(II) carboxylate dimers causes denitrogenation to generate α-azo rhodium(II) carbenoid species as new types of donor/acceptor carbenoids, which then readily react with styrenes to afford 3,5-diaryl-2-pyrazolines with a high degree of enantioselectivity.

A bay-region-selective annulative π-extension (APEX) reaction of perylene diimides (PDIs) has been achieved by means of in-situ generated reactive aryne intermediates. This method provides an efficient one-pot π-extension at the short axis of PDIs in a sequential manner. Mechanistically, an inverse-electron-demand Diels–Alder reaction might be operative for the transformation.

Abstract Chemical phenomena are inherently complex and stochastic, making them difficult to fully understand using conventional ensemble-averaged analytical methods. These methods primarily capture long-lived species and common structural features, limiting the study of transient intermediates and minute structural characteristics. In contrast, single-molecule time-resolved analysis using advanced microscopy techniques, particularly transmission electron microscopy, offers high spatial and tempo

Upon melting, the molecules in a crystal explore numerous configurations, reflecting an increase in disorder. The molar entropy of disorder can be defined by Boltzmann's formula Δ<i>S</i>_d = <i>R</i>ln(<i>W</i>_d), where <i>W</i>_d is the increase in the number of microscopic states, so far inaccessible experimentally. We found that the Arrhenius frequency factor <i>A</i> of the electron diffraction signal decay provides <i>W</i>_d through an experimental

Daptomycin (DP) is effective against multiple drug-resistant Gram-positive pathogens because of its distinct mechanism of action. An accepted mechanism includes Ca²⁺-triggered aggregation of the DP molecule to form oligomers. DP and its oligomers have so far defied structural analysis at a molecular level. We studied the ability of DP molecule to aggregate by itself in water, the effects of Ca²⁺ ions to promote the aggregation, and the connectivity of the DP molecules in th

Phase diagrams and crystallography are standard tools for studying structural phase transitions, whereas acquiring kinetic information at the atomistic level has been considered essential but challenging. The η-to-θ phase transition of alumina is unidirectional in bulk and retains the crystal lattice orientation. We report a rare example of a statistical kinetics study showing that for nanoparticles on a bulk Al(OH)₃ surface, this phase transition occurs nondeterministically through a

Abstract Sulfonylation of 1 H ‐tetrazoles with triflic anhydride in the presence of chiral rhodium(II) carboxylate dimers causes denitrogenation to generate α‐azo rhodium(II) carbenoid species as new types of donor/acceptor carbenoids, which then readily react with styrenes to afford 3,5‐diaryl‐2‐pyrazolines with a high degree of enantioselectivity.

Many chemical reactions go through a cascade of events in which a series of metastable intermediates appear, and crystal nucleation is no exception. Although the consensus on the energetics of nucleation suggests the formation of metastable states preceding the crystal growth, little experimental evidence has been reported for their dynamics at an atomistic level. Operando imaging of two-dimensional nucleation on a defect-free NaCl nanocrystal in carbon nanotubes using a millisecond angstrom-res

As a crystal approaches a few nanometers in size, atoms become nonequivalent, bonds vibrate, and quantum effects emerge. To study quantum dots (QDs) with structural control common in molecular science, we need atomic precision synthesis and analysis. We describe here the synthesis of lead bromide perovskite magic-sized nanoclusters via self-organization of a lead malate chelate complex and PbBr₃^- under ambient conditions. Millisecond and angstrom resolution electron microsc

Diamond and adamantane (<b>Ad</b>) share a <i>T</i>_d-symmetric carbon skeleton, but converting <b>Ad</b> to diamond has been challenging because it requires selective carbon-hydrogen (C-H) bond cleavage and monomer assembly into a diamond lattice. Our approach differs from the conventional high-temperature, high-pressure diamond syntheses. We electron-irradiated <b>Ad</b> submicrocrystals at 80 to 200 kilo-electron volts and 100 to 296 kelvin in vacuum for tens of seconds. This proces

Traditionally, the study of crystal polymorphism has relied on thermodynamics and measurements averaged over time and the crystal's constituents. This work introduces a kinetic approach to phase identification─millisecond cinematographic electron microscopic imaging of the dynamics of phase transitions of crystals of a few nm in diameter. We demonstrate a remarkable impact of the interface energy on the relative stability of the nanocrystal's polymorphs, enabling in situ manipulation of phase tr

Daptomycin (DP) is effective against multiple drug-resistant Gram-positive pathogens because of its distinct mechanism of action. An accepted mechanism includes Ca2+-triggered aggregation of the DP molecule to form oligomers. DP and its oligomers have so far defied structural analysis at a molecular level, and we studied the process by the combined use of dynamic light scattering in water and atomic-resolution cinematographic imaging of DP molecules captured on a carbon nanotube on which the DP

Well-defined heterostructures exhibit emergent properties distinct from their single-phase constituents, enabling advances across diverse technologies. Typically classified as self-assembly and epitaxy, heterointerface formation is generally assumed to proceed unidirectionally and irreversibly at bulk scales. Here we use in situ electron microscopy at 298 K to visualize the heterostructure formation from nanoscale mixtures of intrinsically immiscible salts at ambient conditions, NaCl and NaI. We