A5001388452- X-ray Diffraction in Crystallography
- Crystallization and Solubility Studies
- Magnetism in coordination complexes
- Crystallography and molecular interactions
- Photochemistry and Electron Transfer Studies
- Photochromic and Fluorescence Chemistry
- Ionic liquids properties and applications
- Organic and Molecular Conductors Research
- Electrochemical Analysis and Applications
- Perovskite Materials and Applications
- Luminescence and Fluorescent Materials
- Solid-state spectroscopy and crystallography
- Photoreceptor and optogenetics research
- Metal-Catalyzed Oxygenation Mechanisms
- Electron Spin Resonance Studies
- Spectroscopy and Laser Applications
- Porphyrin and Phthalocyanine Chemistry
- Radical Photochemical Reactions
- Spectroscopy Techniques in Biomedical and Chemical Research
- Molecular Sensors and Ion Detection
- Diamond and Carbon-based Materials Research
- Magneto-Optical Properties and Applications
- Multiferroics and related materials
- Spectroscopy and Chemometric Analyses
- Molecular spectroscopy and chirality
Chuo University
2021-2024
Aoyama Gakuin University
2016-2023
Robert Bosch (Germany)
2020
Japan Science and Technology Agency
2018-2020
National Sagamihara Hospital
2017-2019
National Yang Ming Chiao Tung University
2007-2017
The University of Tokyo
2002-2013
Banaras Hindu University
2007
Abstract Polarization change induced by directional electron transfer attracts considerable attention owing to its fast switching rate and potential light control. Here, we investigate electronic pyroelectricity in the crystal of a mononuclear complex, [Co(phendiox)( rac -cth)](ClO 4 )·0.5EtOH ( 1 ·0.5EtOH, H 2 phendiox = 9, 10-dihydroxyphenanthrene, -cth racemic 5, 7, 12, 14-hexamethyl-1, 4, 8, 11-tetraazacyclotetradecane), which undergoes two-step valence tautomerism (VT). Correspondingly,...
A belt-shaped [8]cycloparaphenylene (CPP) and an enantioenriched Möbius-shaped [10]CPP have been synthesized by high-yielding rhodium-catalyzed intramolecular cyclotrimerizations of a cyclic dodecayne pentadecayne, respectively. This possesses stable chirality isolated with high enantiomeric purity. It is evident from the reaction Gibbs energy calculation that above irreversible are highly exothermic; therefore establishing alkyne cyclotrimerization powerful route to strained molecular strips.
Flapping fluorophores (FLAP) have been developed as a new series of molecular viscosity probes that show polarity-independent ratiometric fluorescence properties.
To alleviate the energy and environmental crisis, in last decades, harvesting by utilizing optical control has emerged as a promising solution. Here we report polar crystal that exhibits photoenergy conversion storage upon light irradiation. The consists of dinuclear [CoGa] molecules, which are oriented uniform direction inside lattice. Irradiation with green induces directional intramolecular electron transfer from ligand to low-spin CoIII centre, resultant light-induced high-spin CoII...
Abstract We have developed an automatic and objective method for detecting human oral squamous cell carcinoma (OSCC) tissues with Raman microspectroscopy. measure 196 independent spectra from different points of one tissue sample globally analyze these using a Multivariate Curve Resolution (MCR) analysis. Discrimination OSCC is automatically objectively made by spectral matching comparison the MCR decomposed standard spectrum keratin, well-established molecular marker OSCC. use total 24...
The polarization switching mechanism is used in various devices such as pyroelectric sensors and memory devices. change mostly occurs by ion displacement. development of materials whose switches via electron transfer order to enhance operation speed a challenge. We devised synthetic crystal engineering strategy that enables the selective synthesis [CrCo] heterometallic dinuclear complex with polar structure, wherein changes stem from intramolecular charge between Co ligand. Polarization can...
Abstract Pyroelectricity plays a crucial role in modern sensors and energy conversion devices. However, obtaining materials with large nearly constant pyroelectric coefficients over wide temperature range for practical uses remains formidable challenge. Attempting to discover solution this obstacle, we combined molecular design of labile electronic structure the crystal engineering orientation lattice. This combination results pyroelectricity purely origin. Here, report polar an [FeCo]...
Using light as a local heat source to induce temporary pyroelectric current is widely recognized an effective way control the polarization of crystalline materials. In contrast, harnessing directly modulate crystal via excitation electronic bands remains less explored. this study, we report FeII spin crossover that exhibits photoinduced macroscopic change upon by green light. When excited relaxes ground state, corresponding can be detected. An analysis structures, magnetic properties and...
Abstract Water is still mysterious despite intensive and extensive studies over the years. Anomalous behavior of water as a liquid yet to be fully comprehended. Here we show that most generally known anomaly water, density maximum anomaly, well accounted for by formation nanometer-size ice crystallite at low temperatures. We spectroscopically that, in cold super-cooled this formed coexists with other two forms water. Multivariate hyperspectral analysis 140 temperature dependent Raman spectra...
An important technique to realize novel electron- and/or proton-based functionalities is use a proton–electron coupling mechanism. When either proton or electron excited, the other one modulated, producing synergistic functions. However, although compounds with proton-coupled transfer have been synthesized, crystalline molecular that exhibit proton-transfer-coupled spin-transition (PCST) behavior not reported. Here, we report first example of PCST Fe(II) complex, wherein lies on N hydrazone...
Photochromic materials have been widely used in various research fields because of their variety photoswitching properties based on molecular frameworks and bond breaking processes, such as homolysis heterolysis. However, while a number photochromic reported so far, there are few reports that show both heterolysis depending the substituents with high durability. The biradicals zwitterions generated by different physical chemical potential applications. Therefore, rational design to control...
Delocalized biradicals have been extensively studied because of fundamental interests to singlet and several potential applications such as two-photon absorption materials. However, many the biradical studies only focus on static properties rigid molecular structures. It is expected that delocalized are sensitive subtle changes structures their local environments. Therefore, dynamic system will give further insight into stable radical chemistry. In this study, we directly probe ultrafast...
Abstract A proton–electron coupling system, exhibiting unique bistability or multistability of the protonated state, is an attractive target for developing new switchable materials based on proton dynamics. Herein, we present iron(II) hydrazone crystalline compound, which displays stepwise transition and transfer at crystal level. These phenomena are realized through with spin transition. Although multi‐step hysteresis has been observed in various systems, corresponding behavior not reported...
Raman spectroscopy of nano-scale materials is facing a challenge developing physically sound quantitative approach for the phonon confinement effect, which profoundly affects band shapes small particles. We have developed new based on 3-dimensional dispersion functions. It analyzes quantitatively in terms particle size distributions. To test model, we successfully obtained good fits observed spectra diamond nanoparticles range from 1 to 100 nm.
We report on an accurate intensity calibration method for low wavenumber Raman spectroscopy. It uses the rotational spectrum of N 2 . The distributions in spectra diatomic molecules are theoretically well established. They can be used as primary standards calibration. ratios Stokes and anti‐Stokes transitions originating from same levels not affected by thermal population. Taking effect rotation–vibration interactions appropriately into account, we able to calculate these theoretically....
Abstract The melting process of 1-butyl-3-methylimidazolium chloride (bmimCl), a prototype room-temperature ionic liquid, has been studied with fast low frequency Raman spectroscopy. Simultaneous tracing the lattice vibrations and trans/gauche conformational marker bands reveals that change in butyl group occurs few seconds after loss vibrations. This finding indicates alkyl chain interaction bmimCl is so strong conformation hardly changes very early stage melting.
Ultralow-frequency Raman spectroscopy that can measure vibrational bands at as low ±10 cm(-1) has enabled facile in situ imaging of polycrystalline microstructures such grains and grain boundaries with high polymorph specificity. We demonstrate this method by investigating microcrystals two distinct polymorphs 1,1'-binaphthyl using a microscope.
We have constructed a multi-channel Raman spectrometer that is capable of recording the low frequency region down to 5 cm(-1) with measurement time few tenths second. An iodine vapor filter, which uses narrow (approximately 0.03 cm(-1)) absorption line for Rayleigh scattering elimination, combined composed single polychromator and charge-coupled device (CCD) camera. Thanks high elimination efficiency over 10(6), spectra microcrystalline L-cystine from -300 1000 are simultaneously measurable...
The geometrical evolution of the reactant and formation photoproduct in cycloreversion reaction a diarylethene derivative were probed using time-resolved absorption spectroscopies visible to near-infrared mid-infrared regions. time-domain vibrational data region show that initially formed Franck-Condon state is geometrically relaxed into minimum excited potential energy surface, concomitantly with low-frequency coherent vibrations. Theoretical calculations indicate nuclear displacement this...
Organic molecules with an aggregation-induced emission (AIE) property have been attracting much attention from the viewpoint of application to solid state emissive materials. For AIE mechanism, quantum mechanical studies proposed restriction intramolecular motion (RIM) model contribution conical intersection (CI) and deduced importance restricted access a (RACI) in potential energy surface (PES). Although these theoretical contributed elucidation phenomena, direct detection reaction dynamics...
Capability to control macroscopic molecular properties with external stimuli offers the possibility exploit molecules as switching devices of various types. However, application such molecular-level has often been limited by its speed and thus efficiency. Herein, we demonstrate ultrafast, photoinduced polarization in crystal a [CrCo] dinuclear complex ultrafast pump-probe spectroscopy visible mid-infrared regions. The was found have time constant 280 fs, which makes fastest...
Abstract Capability to control macroscopic molecular properties with external stimuli offers the possibility exploit molecules as switching devices of various types. However, application such molecular‐level has often been limited by its speed and thus efficiency. Herein, we demonstrate ultrafast, photoinduced polarization in crystal a [CrCo] dinuclear complex ultrafast pump–probe spectroscopy visible mid‐infrared regions. The was found have time constant 280 fs, which makes fastest...
We demonstrated the electrochromism of photochromic radical complexes containing triaryl imidazole: fast photoswitchable pentaarylbiimidazole (PABI) and phenoxyl–imidazolyl complex (PIC).