Tokyo Institute of Technology · Materials Science
Professor Masaki Kawano's research lab specializes in the dynamic structural characterization of transient reactive intermediates—particularly carbenes and radical pairs—using in situ X-ray crystallography under controlled conditions such as low temperature and light irradiation. The lab focuses on understanding the structural and electronic changes during solid-state photoreactions, with an emphasis on the formation and reactivity of short-lived species like triplet carbene and radical pairs in crystalline environments. Their work uniquely combines single-crystal X-ray diffraction, spectroscopy, and theoretical calculations to probe reaction mechanisms at the atomic level in real time. The lab also explores functional porous coordination networks with stimuli-responsive behavior, including reversible guest adsorption and framework dynamics.
Figures are computed from collected data and may differ slightly.
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTThe First in Situ Direct Observation of the Light-Induced Radical Pair from a Hexaarylbiimidazolyl Derivative by X-ray CrystallographyMasaki Kawano, Tomokatsu Sano, Jiro Abe, and Yuji OhashiView Author Information CREST, Japan Science and Technology Corporation, and Department of Chemistry Tokyo Institute of Technology, Tokyo 152-8551 Japan Department of Photo-Optical Engineering Tokyo Institute of Polytechnics Kanagawa 243-0297 Japan Cite this:
A [2+2] cycloaddition reaction has been observed in a number of solids. The cyclobutane ring in a photodimerized material can be cleaved into olefins by UV light and heat. The high thermal stability of the metal-organic salt K2SDC (H2SDC = 4,4'-stilbenedicarboxylic acid) has been successfully utilized to investigate the reversible cleavage of a cyclobutane ring. The two polymorphs of K2SDC undergo reversible cyclobutane formation by UV light and cleavage by heat in cycles. Of these, one polymorp
A net gain: A kinetically assembled, but thermally stable network is obtained using the labile metal species [Cu4 I4 (PPh3 )4 ]. The network uniquely adsorbs I2 by chemisorption through I3 (-) formation. The chemisorbed I2 readily desorbs above 380 K owing to the dynamic motion of the framework. A thermodynamically assembled network physisorbs I2 , which is an exact fit for the channel.
Fast powders and slow crystals: A uniform powder sample of a flexible porous coordination network is prepared in high yield by kinetically controlled synthesis and its crystal structure solved by synchrotron ab initio powder X-ray diffraction (see picture). Crystals of a totally different porous network with larger channels for guest encapsulation are also obtained by thermodynamic control in a slow crystallization process.
A light-induced transient bis(2,4,6-trichlorophenyl)carbene trapped in a yield of ca. 20% in the crystal of the precursor diazomethane was characterized by X-ray crystallography at low temperatures. The most interesting geometrical parameters are the carbenic angle θ and the bond distances between the carbenic carbon and the phenyl carbons. The obtained θ is 142(2)°, while the distances are 1.437(15) and 1.423(16) Å, respectively. These values are significantly different from the corresponding v
Isomerism in covalent organic frameworks (COFs) has scarcely been known. Here, for the first time we show 3D COFs with three framework isomers or polymorphs constructed from the same building blocks. All isomers were obtained as large (>10 μm) crystals; although their crystal shapes were distinctly different, they showed identical FT-IR and solid-state NMR spectra. Our structural analyses revealed unprecedented triple isomerism in 3D COFs (noninterpenetrated <b>dia</b>, <b>qtz</b>, and 3-fold in
Crystalline-state photoreactions of the following diphenyldiazomethanes were investigated by in situ X-ray crystallography, spectroscopy, and theoretical calculations: bis(2,4,6-trichlorophenyl)diazomethane (1-N2), bis(2,4,6-tribromophenyl)diazomethane (2-N2), bis(2,6-dibromo-4-methylphenyl)diazomethane (3-N2), bis(2,6-dibromo-4-tert-butylphenyl)diazomethane (4-N2), (2,4,6-tribromophenyl)-(2,6-dimethyl-4-tert-butylphenyl)diazomethane (5-N2), bis(4-bromophenyl)diazomethane(6-N2), and diazofluoren
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSynthesis, properties, and crystal structure of a novel .mu.-hydrazine-bridged mixed-valence ruthenium(II,III) complex stabilized by hydrazine hydrogen bonds, [RuCl(TMP)2]2(.mu.-Cl)(.mu.-N2H4)(.mu.-S2) (TMP = trimethyl phosphite)Masaki Kawano, Chikara Hoshino, and Kazuko MatsumotoCite this: Inorg. Chem. 1992, 31, 25, 5158–5159Publication Date (Print):December 1, 1992Publication History Published online1 May 2002Published inissue 1 December 1992https://
[Pd(16)Ni(4)(CO)(22)(PPh(3))(4)](2)(-) (1) and [Pd(33)Ni(9)(CO)(41)(PPh(3))(6)](4)(-) (2) were obtained as the two major products from the reduction of PdCl(2)(PPh(3))(2) with [Ni(6)(CO)(12)](2)(-). Their crystal structures as [PPh(4)](+) salts were unambiguously determined from CCD X-ray crystallographic analyses; the resulting stoichiometries were ascertained from elemental analyses. Infrared, multinuclear (1)H, (31)P[(1)H] NMR, UV-vis, CV, variable-temperature magnetic susceptibility, and ESI
Synchrotron powder XRD analysis was used to solve the crystal structure of a kinetically controlled coordination network including tetrathiafulvalene (TTF) guests, which has a large unit cell (15 729(1) Å3). Very short S⋅⋅⋅S contacts among the TTF guests were achieved by confinement in the network pores (see picture). Detailed facts of importance to specialist readers are published as ”Supporting Information”. Such documents are peer-reviewed, but not copy-edited or typeset. They are made availa
Solid-liquid interface synthesis provided a unique way to selectively and efficiently prepare molecular complexes (ML(2)) and metastable porous coordination networks in short crystallization times. In sharp contrast, their solution reactions gave interpenetrated open-framework networks. We succeeded in solving a crystal structure of the metastable network by ab initio powder X-ray analysis.
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